U.S. patent application number 11/980703 was filed with the patent office on 2008-09-25 for prevention and treatment of skin and nail infections using germicidal light.
Invention is credited to William E. Cumbie.
Application Number | 20080234786 11/980703 |
Document ID | / |
Family ID | 27668336 |
Filed Date | 2008-09-25 |
United States Patent
Application |
20080234786 |
Kind Code |
A1 |
Cumbie; William E. |
September 25, 2008 |
Prevention and treatment of skin and nail infections using
germicidal light
Abstract
A method of prevention and treatment of microbial infections
that occur on, or just below, the skin and nails of a person
consisting of electromagnetic radiation to inactivate the microbes
thus rendering them harmless. The treatment consists of irradiating
an area of the skin and nails for a period of time long enough to
inactivate the organisms. Some additional features which are not
integral to the treatment but increase the safety of the treatment
include shielding of non-infected areas from irradiation and a
cover to prevent damage to sight which may result from viewing the
electromagnetic radiation.
Inventors: |
Cumbie; William E.;
(Yorktown, VA) |
Correspondence
Address: |
MEREK, BLACKMON & VOORHEES, LLC
673 S. WASHINGTON ST.
ALEXANDRIA
VA
22314
US
|
Family ID: |
27668336 |
Appl. No.: |
11/980703 |
Filed: |
October 31, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11154707 |
Jun 17, 2005 |
7306620 |
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11980703 |
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10215834 |
Aug 9, 2002 |
6960201 |
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11154707 |
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60355088 |
Feb 11, 2002 |
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Current U.S.
Class: |
607/88 ; 128/898;
606/9 |
Current CPC
Class: |
A61N 2005/0643 20130101;
A61N 2005/0661 20130101; A61B 2018/1807 20130101; A61N 5/0616
20130101; A61N 2005/0654 20130101; A61B 2018/2015 20130101; A61B
2018/00452 20130101; A61N 5/0624 20130101; A61L 2/10 20130101 |
Class at
Publication: |
607/88 ; 128/898;
606/9 |
International
Class: |
A61N 5/06 20060101
A61N005/06; A61B 17/00 20060101 A61B017/00; A61B 18/18 20060101
A61B018/18 |
Claims
1. A method for the treatment of skin and nail infections caused by
organisms comprising: selecting a germicidal radiation spectra and
applying germicidal radiation in sufficient strength based on said
spectra to cause antigenosis and geneticide of said organisms.
2. A method according to claim 1 wherein antigenosis and geneticide
is the result of germicidal radiation induced cross-linking of
pyrimadine bases and formation of dimers within the genetic
material of the organisms.
3. A method according to claim 1 wherein said germicidal radiation
is generated by one of the group consisting of a mercury lamp, a
xenon lamp, and a laser.
4. A method according to claim 1 further comprising the steps of
identifying efficacy loss as a penetration percentage through a
particular medium such as nails and for a selected radiation
spectra to said organisms and applying germicidal radiation
strength sufficient to compensate for said loss.
5. A method according to claim 1 further including the step of
unfavorably modifying the environment for the organisms
6. A method according to claim 1 further including the step of
enhancing a medium for transmitting germicidal radiation.
7. A method according to claim 1 further including the step of
augmenting treatment with antibiotics.
8. A method according to claim 1 for treatment of one of the group
consisting of humans and animals.
9. A method according to claim 1 wherein said germicidal radiation
is applied at dosages of from about 5 mJ/cm.sup.2 to about 500
J/cm.sup.2.
10. A method according to claim 9 wherein said germicidal radiation
is applied at from about 5 mJ/cm.sup.2 to about 100 J/cm.sup.2.
11. A method according to claim 9 wherein said germicidal radiation
spectra includes radiation from between 200 nm and 400 nm.
12. A method according to claim 11 wherein said germicidal
radiation spectra includes radiation in the UVC range.
13. A method according to claim 1 further including the step of
adding other spectra generally not considered germicidal to enhance
the effect of the application of germicidal light selected from a
group of light with spectra between 400 nm and 1,000,000 nm.
14. A treatment device for preventing and treating skin and nail
infections comprising: a light source selected from the group of a
tunable laser, a xenon lamp, a plurality of lamps, and a mercury
vapor lamp; a light exposure measurement means selected form the
group of a timer, a radiometer, and a spectrometer; and a treatment
record storage device selected from the group of an electronic
memory, and a camera.
15. The treatment device of claim 13 further including: an
attachment for providing light to a preselected location, selected
from the group of a hose, a wand, a mouth guard, and fiber optic
cable.
16. The treatment device of claim 13 further including: a safety
device selected from the group of Teflon coated applicators, a
flexible wand, a shield, safety labels, ground fault protectors,
and optically transparent barriers.
17. A method for the treatment of nail infections caused by
organisms comprising the step of applying electromagnetic radiation
as a specific composition of matter in order to cause antigenosis
and geneticide of said organisms.
18. The electromagnetic radiation of claim 16 being a specific
composition of matter with photons capable of penetrating a nail
and capable of damaging the genetic material of an organism
19. The electromagnetic radiation of claim 16 being a specific
composition of matter comprised of light between 200 nm and 400
nm.
20. The method of claim 1, further including the step of preventing
skin and nail infections caused by organisms by selecting a
germicidal radiation spectra and applying germicidal radiation in
sufficient strength based on said spectra to cause antigenosis and
geneticide of said organisms.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation in part of U.S.
application Ser. No. 10/215,834, which claims the benefit of U.S.
Provisional Application 60/355,088 with filing date of Feb. 11,
2002.
BACKGROUND
[0002] 1. Field of Invention
[0003] This invention relates to preventing and treating skin and
nail infections using germicidal radiation to inactivate and kill
organisms that cause such infections.
[0004] 2. Background of the Invention
[0005] The germicidal effects of certain types of light have been
recognized for many years. As early as the late 1890's certain
types of ultraviolet light were found to have a germicidal effect.
However, the wavelengths of light found to be germicidal have very
little power to penetrate which limited their usefulness in
treating infections. The most germicidal band, labeled UVC and
extending from 240 to 280 nm, is totally absorbed by the atmosphere
before it reaches the Earth's surface. Published research indicates
that UVC can only penetrate the skin about 0.1 mm. Although
germicidal light was found useful to sterilize air or water and to
treat hard surfaces such as laboratory benches, its lack of
penetration made it appear unsuitable to treat skin and nail
infections.
[0006] Niels Finsen received the 1903 Nobel Prize in Medicine for
his discovery that light in the ultraviolet region could be used to
treat skin tuberculosis, a very serious disease at that time. The
treatment as described in the 1903 Nobel Prize acceptance speech
consisted of concentrating the rays of the sun and eliminating its
longer heat producing rays or using a carbon arc lamp. The skin is
exposed for an hour or so until it becomes red and inflamed. This
treatment was repeated as necessary until the skin scarred over and
then later grew in clear. The treatment was described as having no
unpleasant effects, but was expensive, and required constant
supervision. The light used had a very low percentage of UVC and it
was thought that the main effect of the light used was to stimulate
the body's natural defenses. It was thought that germicidal light
could not effectively penetrate the skin to treat the infection but
that the main purpose of the light was to stimulate the body's
natural defenses.
[0007] This type of treatment for skin tuberculosis and several
other skin diseases continued through the 1950's but was eventually
replaced by the use of antibiotics. Early use of ultraviolet light
was much more of an art than a science. In the early 1900's science
was just beginning to form its modern theory of the composition of
light and the science of genetics was many decades off. Thus
researchers did not have the theoretical knowledge of how
germicidal light damages genetic material to guide them in their
treatments.
[0008] Early practitioners of phototherapy for the treatment of
skin infections were aware of the germicidal effects of light but
did not think they contributed significantly to UV phototherapy. In
Ultra-Violet Radiation and Actinotherapy (Russel, 1933) it was
noted that `Ultraviolet light is absorbed by the protoplasm of the
organism, and in a culture, or on the surface of a wound, one
bacterium will protect a second lying under it; so in a lesion like
lupus very little beneficial therapeutic effect can be considered
to be due to the bactericidal effects of the rays. It is due rather
to the increased lymphocytosis in the part, and stimulation of
cicatrisation.` (Russel, 1933, pg. 288). The text also notes that
`the absorption by the skin of very short wave-length, is very
great, all rays shorter than 3000 angstroms [300 nm] being absorbed
by a later of epidermis 0.1 mm in thickness` (Russel, 1933, pg.
272-273). The lamps which were used to treat skin infections had at
least 95% of their energy emitted at wavelengths over 300 nm and
thus had very little energy in wavelengths considered germicidal.
This compares to modern low pressure mercury germicidal lamps where
95% of light is emitted at 254 nm--almost the exact opposite of
earlier lamps used to treat skin disorders.
[0009] U.S. Pat. No. 1,856,969 by Reiter and Gabor in 1932
describes a type of phototherapy to modulate living tissue that was
used as part of empirically based treatment of skin disorders. The
patent describes the use of UV to stimulate the natural defenses of
the body and includes a filter to prevent light less than 320 nm
from reaching the skin since light below 320 nm was felt to be
detrimental to treatment. This patent illustrates that most early
UV therapy was focused on the stimulating effects of UV and not on
its germicidal qualities since the wavelengths considered
germicidal (less than 315 nm) were considered to be detrimental to
treatment.
[0010] Treatment of skin diseases continued on an empirical basis
through the 1950's with a multiplicity of units being produced each
with different approximated guidelines of how to best use them for
various disorders and infections. The empirical basis of treatment
of these disorders was based on judiciously applying ultraviolet
light to cause erythema (redness) to develop. The treatment was
then adjusted to bring about various degrees of sunburn depending
on the disorder being treated. Mild erythema (slight redness) was
assigned a value of E-1 while the most sever erythema (blistering
and third degree burns) was assigned an E-4. The most serious
infections often merited a treatment bringing about an E-4 erythema
for a sustained period. The induced erythema was thought to
stimulate the body's defenses, particularly increasing the
bactericidal ability of the blood. Although this was the most
prevalent theory of why this treatment was efficacious there was no
absolute consensus. The lack of consensus with regard to how this
type of treatment worked and the large number of lamps that were
being marketed in the first half of the twentieth century was
probably bewildering to many doctors. Nevertheless, in the absence
of modern antibiotics, even the empirical use of ultraviolet light
to treat skin infections.
[0011] Electrotherapy and Actinotherapy; A Textbook for Student
Physiotherapists authored by E. B. Clayton and published in 1952
(2.sup.nd edition) shows of the state of the art of phototherapy
before use of modern antibiotics caused this form of treatment to
lose favor. This 451 page textbook covers all aspects of
phototherapy beginning with the theory, the type of equipment used,
and treatment of various types including skin disorders. Portions
of the treatment section for skin tuberculosis read as follows,
"The Finsen-Lomholt water cooled carbon arc or the Kromayer lamp is
employed. The latter has the disadvantage that its spectrum
includes a quantity of abiotic rays which are not required and
merely increase the superficial inflammation . . . . The initial
exposure is commonly five times a fourth degree erythema." (pgs.
413-414). This extract of the book notes that abiotic (germicidal)
light is not considered helpful for treatment. It also shows that
dosages for treatment were based on empirically derived rules of
thumb related to how severe the produced erythema was. Although
almost 100 pages are devoted to describing various treatments there
is no mention of dosage in terms of the amount of energy applied
nor is there mention of any specific wavelengths.
[0012] Empirical use of ultraviolet light had a number of
undesirable side effects including a wide spectrum of light
including high amounts of UVB light now known to be carcinogenic.
The relative amount of germicidal light was extremely low which
made any possible benefit due to its inclusion very small and
probably undetectable. Also, the cure rate was also much lower than
can be expected with a well understood theory of how germicidal
light inactivates organisms. Thus, when safer and more effective
antibiotics were introduced in the 1950's the practice of
empirically using ultraviolet light to treat skin infections was
quickly abandoned by the medical profession in general. While
ultraviolet light may still be used to empirically treat skin
infections in isolated areas of the world its general use has been
abandoned.
[0013] There appears to have been no application of the recent
advances in genetics, air handling, and water and wastewater
disinfection to transform the use of germicidal light to
scientifically treat skin infections. The present invention
combines these advances in other fields to develop a novel and
unique approach to scientifically treat skin and nail infections in
a manner that increases the efficacy of treatment while minimizes
the side effects of such treatments.
[0014] It should be noted that there is no indication that this
type of treatment was ever applied to treating nails. While the
text discuss a number of different disorders affecting different
parts of the body (including skin, nose, throat, anus, etc.) the
mention of nails is not found in any text. This is understandable
given the limited ability of nails to transmit light in the
ultraviolet range and the fact that nail diseases in general are
less life threatening than skin infections.
[0015] With the discovery of DNA and RNA in the 1950's and the
subsequent development of the science of genetics, scientists
discovered that each cell contained a highly sophisticated code to
permit the cell to reproduce. Later, it was found that certain
kinds of ultraviolet light could damage this genetic material and
prevent a cell from reproducing. This knowledge was applied in many
different fields including water and wastewater treatment (where it
was used to disinfect water), to sterilize surfaces, and to
sterilize air. However, it was not applied to treat skin
infections. This was perhaps due to several reasons including the
following: [0016] The widespread knowledge that UV cannot penetrate
deeply made it a less than ideal candidate to treat an infection
that may not be totally on the surface of the skin. Since it is
well documented that light less than 300 nm cannot penetrate below
the first 0.1 mm of the epidermis, its penetrating power was
thought insufficient to treat infections. [0017] The old empirical
use of UV light made use of lights of varying characteristics and
strengths. It is likely that these lights cause some pain and
tenderness due to their non-specificity. Also, since there was no
knowledge of how the light cleared infections, it was applied in a
broad manner and probably had significant side effects due to
overdosing including cancer due to high level of carcinogenic
UVB.
[0018] While Niels Finsen is cited as the founder of phototherapy
by many authors, the industry has all but abandoned the use of
ultraviolet light to treat infections and has instead concentrated
on the visible and infrared part of the spectrum from 400 nm to
1000 nm. The invention disclosed in this application builds on
Finsen's work and extends it in new and innovative ways by
combining new knowledge of genetics and advances in the use of
ultraviolet light to disinfect air and water. The combination of
diverse knowledge that the invention builds on is not generally
known to those skilled in the art of phototherapy and when this new
knowledge is combined with the existing empirical base provided by
Finsen and other early phototherapists, new and unobvious
applications of this knowledge to prevent and treat skin and nail
infections emerge.
[0019] The germicidal effects of electromagnetic radiation have
been recognized for many years. Currently, germicidal radiation
(also called germicidal light) is being used more frequently at
water and wastewater treatment plants to render water-borne
pathogens harmless. Additionally, germicidal light is used to
sterilize and purify air, particularly in laboratories and medical
establishments. It is also used to sterilize equipment at such
establishments. Germicidal light has been used for several years to
sterilize and disinfect food products and has also been used to
sanitize the hands to prevent the spread of germs to other persons.
Over the years a large body of knowledge concerning germicidal
radiation has been developed but has not been systematically
applied to address important problems with respect to treating skin
and nail infections.
[0020] While germicidal light is not used by itself to treat skin
and nail infections, certain types of light that are considered
non-germicidal are frequently combined with other additional
chemical compositions to treat existing psoriasis, rashes, and
other non-infectious skin disorders. It is believed that this type
of treatment, termed phototherapy, is effective because it has an
immunosuppressive effect that permits the body to heal itself.
Recently, lasers alone have been successfully used to treat
psoriasis by clearing localized chronic plaque. Phototherapy is
also used to treat jaundice which is also a non-infectious
disorder. However, no method of using germicidal light alone has
been discovered to successfully treat existing microbial infections
nor has this type of light been used as a preventative treatment
for infections.
Perceived Inability of Germicidal Light to Penetrate Skin and
Nails
[0021] The main reason that germicidal light alone has not been
used to prevent and treat skin and nail infections is that the most
potent germicidal light is in the UVC range (240 nm to 300 nm) and
this type of light cannot penetrate the skin and nails deeply.
Significantly less than 1% of UVC light can penetrate nails or the
deeper than 0.1 mm of skin (i.e. does not penetrate the
epidermis).
[0022] UVB (280 nm 315 nm) while not generally considered
germicidal also has some limited germicidal ability particularly in
the 280 nm to 300 nm part of the spectrum. However, it also has
limited penetrability. For example UVB it is estimated that less
than 5% of light at 315 nm penetrates the epidermis (approx. 0.125
mm deep) or nails. The perceived inability of germicidal light to
penetrate the skin and nails is one of the major reasons that this
type of light has not been used to prevent and treat infections. If
the light cannot penetrate skin or nails and reach the infectious
organisms it is of no use for treating infections. However, it is
this difference between no penetration and little penetration that
the disclosed invention makes innovative and unobvious use of.
Although less than 1% of UVC light can penetrate nails or can
penetrate skin deeper than 100 mm, the less than 1% of light that
is able to penetrate deeper is sufficient to prevent and treat skin
and nail infections when applied properly.
[0023] Less than 8% of UVB at 315 nm can penetrate nails or skin
deeper than 0.1 mm. This is much greater than the penetration
ability of UVC, however, given its lower germicidal ability it does
not appear to be as effective treatment for infections.
Nevertheless, UVB can be used germicidally to treat infections if
it is of sufficient strength or if it is accompanied by use of UVC
light.
[0024] There is a large amount of literature that teaches that
germicidal light cannot penetrate well. The Physics Society in its
July 1998 paper titled "Ultraviolet Radiation and the Public
Health" notes that "UVC, used in germicidal lamps, causes almost no
damage because of its low penetration of the skin." INTERSUN, the
global UV project sponsored by the United Nations indicates only 5%
of UVC (at 254 nm) can penetrate to approximately a quarter of the
depth of the epidermis and less than 1% can penetrate more than
half the depth of the epidermis. Many other sources indicate that
UVC cannot penetrate the skin or can do so only to a very limited
depth. However, this depth is sufficient to treat infections since
organisms are particularly susceptible to germicidal radiation.
Also, with respect to nail infections, the additional radiation
required to penetrate the nail is not harmful to the nail since it
is composed of dead keratin.
UVC Dose Necessary to Inactivate Microbes
[0025] A second major reason the use of UV has not been
contemplated are the relatively high doses necessary to kill some
types of organisms. However, it has been found that it is not
always necessary to kill organisms to render them harmless. It has
been shown that organisms can be inactivated and rendered harmless
using far less radiation than is necessary to kill them completely.
Therefore, although its use as a treatment for has been overlooked
in the past, electromagnetic radiation of sufficient strength can
be used to treat human and animal infections.
[0026] There are several publications that note that organisms can
be rendered harmless with less energy than is necessary to kill
them. The inactivation of organisms by damaging RNA and DNA and
preventing them from reproducing is a method used for disinfection
of highly transparent potable water and is discussed in more detail
in U.S. Pat. No. 6,129,893 to Bolton. The patent describes a method
for preventing the replication of Cryptosporidium parvum using
ultraviolet light. This patent indicates that ultraviolet light can
inactivate bacteria (as measured by infectivity studies) at doses
that are 3% to 10% of the dose necessary to actually kill the
organisms (as measured by microscopic examination of ruptured
membranes). The method of inactivation is described as damage to
the DNA and RNA that prevents the organisms from replicating. Since
organisms are not long-lived in themselves, they are unable to
continue to cause infection if they are unable to replicate. This
discovery is applied to the inactivation of a pathogen in drinking
water to render it safe for consumption. However, the method is
only to irradiate one type of organism and then only in highly
transparent drinking water.
[0027] The EPA guidance manual on Alternate Disinfectants and
Oxidants (April 1999) devotes Chapter 8 to a discussion of
germicidal UV as a disinfectant for drinking water. The manual
notes that a UV wavelength of 240 to 280 nm is highly absorbed by
the RNA and DNA of a microorganism. The absorbance of UV by the
organisms results in the damage to the organism's ability to
reproduce. The damage is often caused by the dimerization of
pyrimidine molecules. A dimer is a molecule consisting of two
identical simpler molecules and dimerization is the process of
linking the two molecules together. Dimerization of the pyrimidine
molecules distorts the DNA helical structure. The EPA guidance
manual also notes that the dose to inactivate 90% of most types of
organisms is very low with a typical range of 2 to 6 mJ/cm.sup.2.
The manual notes that the germicidal radiation can be generated by
a number of sources including a low pressure mercury lamp emitting
at 254 nm, a medium pressure lamp emitting at 180 to 1370 nm, or
lamps that emit at other wavelengths in a high intensity pulsed
manner.
[0028] It should also be noted that it is not necessary to kill and
inactivate all organisms in order to effect a cure for an
infection. If a substantial amount of the organisms that have
caused an infection are destroyed or rendered inactivated, the
body's natural defenses will often work to clear the infection.
Thus, doses of radiation necessary to effect a cure for an
infection may be much lower than those necessary to sterilize an
area by total destruction of all organisms.
[0029] While germicidal light is often said to inactivate organisms
by damaging their genetic material and preventing them from
reproducing, germicidal light can be applied in higher dosages to
damage enough of the genetic material in the cell and prevent it
from being able to properly function, thus leading to its death.
For example, mRNA (messenger RNA) is used to control cellular
processes, however, if it is severely damaged it cannot perform
this function.
UVB as Germicidal Light
[0030] While UVB light has some germicidal qualities it is not
often used to inactivate or kill organisms. Although approximately
10 times more UVB light can penetrate a given depth of skin and
nails than UVC light, its lower germicidal ability does not make it
as attractive a choice. UVB is also considered the band of UV that
causes the most damage to skin, and is therefore considered more
carcinogenic, and is thus avoided where possible. Additionally, UVB
light is more difficult to generate than UVC light which is easily
produced by a mercury vapor light (which is similar in manufacture
to a fluorescent light). Nevertheless, UVB can be used germicidally
and it may be desirable to use it particularly in conjunction with
UVC light. The portion of the UVB range that adjoins the UVC range
(UVB between 280 nm and 300 nm) is almost as germicidal as some
bands of UVC. Practitioners of photobiology sometimes term UV light
between 200 nm and 300 nm as `Far UV` light (as opposed to `Near
UV` light which is often listed in the range of 300 to 400 nm). The
current invention makes use of UVB for treatment of skin and nail
infections even though most literature ignores its germicidal
ability and teaches that UVB does not penetrate deeply. The
invention also encompasses Near UV light in the range of 200 nm to
300 nm due to its germicidal nature.
Other Types of Germicidal Radiation
[0031] U.S. Pat. No. 5,900,211 shows that it is not only UVC and
UVB that can be used to sterilize water and food. Dunn discusses
the use of pulsed polychromatic light to inactivate organisms. Dunn
uses much lower amounts of energy to inactivate an organism than
would be necessary to destroy it by excessive heat. However, Dunn
applies this technology only to the sterilization of food and other
materials and does not contemplate it for treatment of skin or nail
infections. This is presumably because of the perceived inability
of the light to penetrate the skin or nails. (Dunn indicates that
the effectiveness of the light is dependent on its ability to
penetrate a medium effectively).
Prior Art Using UVC to Kill and Inactivate Organisms
[0032] U.S. Pat. No. 6,254,625 shows an apparatus to sterilize
hands to prevent the spread of infectious organisms. This apparatus
makes use of light to sanitize the surface of the hands to prevent
infections from spreading form person to person. In all of its
embodiments it consists of at least two items. It makes use of
light to kill organisms along with either additional light to
recuperatively heal the skin that has been irradiated or the use of
ozone to increase the efficiency of killing organisms. The
recuperative healing light uses the phenomenon of photoreactivation
whereby cells and organisms that have been damaged can repair the
damage using such light of a different wavelength. The inclusion of
this source of light as part of the apparatus indicates that the
disease causing organisms are killed and not merely inactivated
otherwise they too could repair damage by photoreactivation.
Additionally, the patent does not contemplate the use of the
apparatus to treat an infected area of the skin and it makes no
mention of treating any infection of the nails using
electromagnetic radiation. The apparatus relies on the use of ozone
to kill any organisms under the nails or shielded by debris and
notes incorrectly that UVC radiation will not penetrate the nail.
Rosenthal appears to be unaware that germicidal UV can penetrate
the skin and nails and is used to treat infections.
[0033] U.S. Pat. No. 6,283,986 discusses the use of UVC radiation
to treat wounds. However, Johnson only applies radiation to open
wounds, which can be readily exposed, and notes that "given the
short wavelength of UVC, no penetration of the underlying tissue
would be expected." The patent makes no mention of skin infections
and mention of the nails is totally absent from the application
although nail infections comprise a large part of total dermal
infections. Possibly, the reason the patent only applies to wounds
is that by their nature wounds are open and therefore capable of
having their surfaces irradiated. It appears that Johnson is also
unaware of the ability of germicidal radiation to penetrate the
skin and nails.
[0034] It is the misconception that germicidal light cannot
penetrate skin and nails which has in part prevented the discovery
that germicidal radiation, including UVC, can indeed penetrate to a
depth sufficient to be used successfully to treat skin and nail
infections. While it is true that skin and nails will absorb a
large percentage of UVC, enough can penetrate to successfully treat
and prevent infections.
Nail Infections and Treatment
[0035] Nail infections are a particularly significant problem in
the general population, affecting an estimated 5% to 15% of the
overall population (approximately 15 to 45 million people). This
percentage is significantly higher in the elderly age group and
among athletes and other individuals who have high moisture in the
area of their feet. Nail infections are often caused by fungus and
this type of infection is termed onychomycosis. Currently, the
preferred method for the prevention and treatment of skin and nail
infections relies on application of topical medications or
ingestion of medications. These medications are used to treat an
existing infection, not for the prevention of an infection. Cost of
treatment using medication can be between $600 and $1200 per course
of treatment and can last three to six months. This is the amount
of time it takes the medication to be incorporated into the nails.
Another one to six months is then required for the nail to become
free of infection. It should be noted that the cost noted above
does not take into account doctors visits or diagnostic testing to
determine if the patient can tolerate the medication (many
medications can cause liver and other damage).
[0036] The problems associated with oral anti-fungal medications
can be illustrated by several quotes from the clinical testing
results for Itraconazole capsules (marketed under the trademark
name SPORANOX.RTM. manufactured by Janssen Pharmaceutica, Inc.)
which was the most prescribed anti-fungal in the U.S. in 1996. The
success rate for treatment of onychomycosis of the toenail is
reported as follows--"Results of these studies demonstrated
mycological cure . . . in 54% of the patients. Thirty-five (35%) of
patients were considered an overall success (mycologic cure plus
clear or minimal nail involvement with significantly decreased
signs) and 14% of patients demonstrated mycological cure (clearance
of all signs, with or without residual nail deformity)." With
respect to adverse reactions--"SPORANOX.RTM. has been associated
with rare cases of serious hepatoxicity, including liver failure
and death. Some of the cases had neither pre-existing liver disease
nor a serious underlying medical condition." In a study of 602
patients treated for systemic fungal disease, "treatment was
discontinued in 10.5% of the patients due to adverse events."
[0037] Although it is relatively rare, death is another serious
side effect of oral antifungal medications. The two most popular
antifungal medications used to treat nail infections were
implicated in a total of 35 deaths in the U.S. between 1996 and
2001. This caused the FDA to issue a health advisory for these
medications in May of 2001.
[0038] Although the currently preferred method of treating nail
infections is the use of oral medication, there are several other
treatments in use. There are several topical applications that are
used to treat fungal infections of the nails. However, these have
an even poorer success rate than oral medications and the
infections tend to re-occur.
[0039] U.S. Pat. No. 6,090,788 to Lurie shows destruction of fungal
infections of the nails by introducing a pigment into an infected
area and then heating the pigment in the infected area with a laser
in order to raise the temperature high enough to kill the organisms
that have caused the infection by excessive heating. The energy
listed in the preferred embodiments is from 5 to 15 J/cm.sup.2 and
it has a relatively long wavelength (generally 500 to 700 nm) in
order to penetrate the nail. The high amount of energy and long
wavelength of light is great enough to cause excessive heating of
the surrounding area thus destroying the organism. However, such
high energy levels also have undesirable effects on the surrounding
tissue such as redness and swelling.
[0040] Lurie incorrectly notes that typical fungi do not have
pigment and, therefore, cannot absorb light. However, the fact is
that all cells will absorb light at a wavelength of between 240 and
280 nm since the DNA in the organism will absorb light at this
wavelength. Also, Lurie is not cognizant of the fact that organisms
can be inactivated at much lower doses than those necessary to
destroy them by excessive heat. Due to the complicated nature of
the treatment, U.S. Pat. No. 6,090,788 is proposed as a method to
treat an infection, not to prevent one.
[0041] Lurie also notes that the light he uses for treatment must
easily penetrate the skin which is something that UV does not do.
Thus it would not be a natural extension of Lurie's treatment to
use UV light to directly treat nail infections.
[0042] Lurie notes "there is a widely recognized need for, and it
would be highly advantageous to have, a phototherapy method for
treating skin and nail pathogens and a pharmaceutical composition
to effect same." It may be added that there is even a greater need
to treat skin and nail infections using germicidal radiation only,
particularly if said radiation could be effective at a much lower
dose and not have the side effects associated with high energy
lasers.
BACKGROUND OF INVENTION
Objects and Advantages
[0043] Accordingly, several objects and advantages of the invention
are:
[0044] a) A method to treat the infected area directly thus
eliminating the need to use oral medications that affect the entire
body, may have serious side effects (including death), and have
only a limited success rate for treating infections.
[0045] b) A means to treat the infected area using a very small
number of treatments (one to perhaps a dozen) over a short period
of time (generally less than one month) as opposed to the need to
ingest oral medication periodically for three months or more.
[0046] c) A means to treat an infection much more cost effectively
that the current cost of $600 to $1200 per course of treatment plus
the additional costs of monitoring for side effects, etc.
[0047] d) A means to treat an infection in much less time
(generally less than a month) as opposed to having to wait three to
six months for the medication to take effect.
[0048] e) A means, which treats the infection using a minimal
amount of radiation to inactivate the organism instead of radiation
treatments using a large amount of energy to destroy an infection
by excessive heat, thus greatly reducing the possibility of
complication arising from using excessive amounts of energy and
limiting the amount of potentially carcinogenic radiation that may
need to be applied to effect a cure.
[0049] f) A means to directly treat infections using radiation
without first having to introduce an artificial pigment into the
area about to be treated, saving time, cost, and eliminating the
chance of side effects resulting from inducing the pigment.
[0050] g) A means to prevent infections before they become
established, by limiting costs, potential side effects, and the
long length of time it takes to act.
[0051] h) A means to prevent infections before they become
established infections which is particularly valuable to those who
are predisposed to infections or persons that such infections pose
a significant threat.
[0052] i) A device to accomplish the methods and means of
preventing and treating skin and nail infections.
[0053] Still further objects and advantages will become apparent
from a consideration of the ensuing description and drawing.
SUMMARY OF INVENTION
[0054] The invention, a method, means, and device to prevent and
treat skin and nail infections, uses germicidal light to inactivate
and/or kill the organisms that cause infections. The method of
treatment consists of irradiating the portion of skin and nail to
be treated using electromagnetic radiation of a germicidal nature.
The method utilizes a previously unrecognized ability of germicidal
light to penetrate the skin and nails sufficiently to successfully
treat and prevent infections. Said electromagnetic radiation
damages the organisms that cause skin and nail infections and
disables their ability to replicate. Without the ability to
replicate the organism cannot continue to infest the skin and
nails. The infection is thereby prevented if it has not yet begun
and it is cured if the infection already exists. Said invention is
also referred to as "method to treat infections" in this
application. The device disclosed is that necessary to execute the
method described in this application.
BRIEF DESCRIPTION OF DRAWINGS
FIGS. 1-10
[0055] FIG. 1 is a diagram showing Light passed through a prism
with light split and showing UV and Infrared.
[0056] FIG. 2 is a chart showing the Divisions of Ultraviolet light
(UVA, UVB, UVC, Far UV, and Near UV).
[0057] FIG. 3 is a diagram showing the Depth of penetration of
Ultraviolet through skin.
[0058] FIG. 4 is a diagram showing the Formation of pyrimidine
dimers (crosslinking) in DNA cause by Ultraviolet light.
[0059] FIG. 5 is a chart showing the relative effectiveness of
various wavelengths on pyrimidine dimerization (crosslinking) of
DNA.
[0060] FIG. 6 is a chart Action spectra showing relative
effectiveness of pyrimidine (6-4) pyrimidone adduct formation of
DNA at various wavelengths.
[0061] FIG. 7 is an environmental perspective of the invention for
treating nail infection or disorder.
[0062] FIG. 8 is an environmental perspective of the invention for
use in treating skin infection such as acne.
[0063] FIG. 9 is an environmental perspective of the invention for
use in preventing nail infection.
[0064] FIG. 10 is an environmental perspective of the invention for
use in preventing a skin infection such as athletes foot.
[0065] FIG. 11 is an environmental perspective of a Device to
prevent and treat skin and nail infections
[0066] FIG. 12 is an environmental perspective of Special
attachments to device to prevent skin and nail infections according
to a further embodiment of the invention.
DETAILED DESCRIPTION OF INVENTION
[0067] Why Germicidal Light has not been Used Before to Treat Skin
and Nail Infections
[0068] The germicidal effects of electromagnetic radiation have
been recognized for many years. However, the germicidal effects of
electromagnetic radiation have not been recognized as a method for
the prevention and treatment of skin and nail infections.
[0069] While UV light was used in the first half of the twentieth
century to treat skin diseases, the primary range of the light was
the UVA range and to the lesser extent the UVB range. The UVC range
was known to be germicidal during that time period, although how it
exerted its germicidal effect was unknown. There was no thought of
using the primary germicidal range of UV to treat skin and nail
infections because the literature taught that such light could not
penetrate below 0.1 mm. Thus the benefit attributed to UV light to
heal infections was not primarily germicidal. In fact one text
explains the biological effect of germicidal radiation as follows,
`Ultraviolet light is absorbed by the protoplasm of the organism,
and in a culture, or on the surface of a wound, one bacterium will
protect a second lying under it; so in a lesion like lupus very
little beneficial therapeutic effect can be considered to be due to
the bactericidal effects of the rays. It is due rather to the
increased lymphocytosis in the part, and stimulation of
cicatrisation.` (Russel, 1993, pg. 288). This perception that
germicidal light could not penetrate sufficiently to be effective
caused researchers to concentrate on the longer ranges of UV (above
315 nm) instead of the part of the band considered
germicidal--primarily light below 315 nm.
[0070] Additionally, phototherapy in the first half of the
twentieth century was primarily an empirical art. There were a
large number of different kinds of lamps in the UV and non-UV range
and their multiplicity prevented standardization of applied
dosages. Instead, approximate exposure times were given for
irradiation for an approximate length of minutes at an approximate
distance. These distances and times were very approximate and
depended on the type of lamp (each having different spectral
characteristics) and how long the lamp had been in service since
their output declined rapidly with use. One very detailed text on
this type of treatment ("Ultraviolet Radiation and Actinotherapy"
by E. H. Russel and W. K. Russel, 1933, 748 pages) has no mention
of dosages to be applied in terms of energy such as Joules or
Watt-seconds per area treated but relies solely on rule of thumb
application rates.
[0071] There are several possible reasons why UVC was not given an
adequate trial as a treatment for skin and nail infections: [0072]
First, it is commonly known that wavelengths less than about 315 nm
cannot easily penetrate nails. Based on experience and limited
testing of the penetration of 254 nm through human nail plates,
less and 1% and perhaps as little as 0.001% ( 1/10,000th) of 254 nm
light penetrates through a typical nail plate. However, it is
important to recognize that fungi are mainly in the nail plate, and
that UVC is so easily generated and so well tolerated that even an
attenuation of 10,000 does not preclude effective treatment. For
example, fungi are killed in a fraction of one second of exposure
to a small UVC lamp. Multiplying this fraction of a second by
10,000 results in an exposure time in the range of 10 to 100
minutes of exposure time, i.e. a practical treatment time.
Additionally, stronger UVC lamps are available which can further
reduce necessary exposure times. Of particular importance also are
lasers which can be tuned to a precise wavelength of light focused
on the area of infection and which can deliver high doses of
coherent light that can better penetrate skin, nails, and the
infections themselves. [0073] A second reason that UVC therapy has
not been tried may be a misunderstanding of the dose required to
effect a cure. It is not necessary to kill an organism to prevent
it from sustaining an infection. It is possible to inactivate an
organism by damaging its genetic material sufficiently to prevent
it from being able to reproduce. Extensive studies of the dosage of
UVC necessary to inactivate pathogenic organisms in drinking water
indicate that often only 3% to 5% of the energy necessary to kill a
particular organism (as measured by rupture of an organism's
membrane) will cause it to be inactivated (as measured by
infectivity studies) and unable to sustain an infection. Since this
research has been conducted in a non-medical field it is not
general knowledge in the community of researchers most likely to
investigate treatment of infected nails. Many bacteria experience a
2 log inactivation (99%) at a dose of 1 to 12 mj/cm2 which is an
achievable dosage even taking into account a low skin and nail
transmissivity rate. [0074] A third reason that phototherapy with
UVC has not been pursued is that few people other than a mammalian
photobiologist appreciate how well UVC exposure is tolerated by
human skin. It is well known that the UVC dose causing a minimal
(pink) sunburn is substantially less than that for UVB. This
minimal sunburn dose is ample for germicidal effect on superficial
organisms. Much less well known, is the fact that human skin
tolerates hundreds of times this minimal dose very well. Thus large
doses of germicidal radiation can be safely applied with the high
doses being capable of offsetting the low penetration rate of UVC.
[0075] Finally, many investigators may not recognize that it is
likely that dermatophytes, the major cause of nail infections and
some skin infections, are quite sensitive to UVC. The organisms are
adapted to living without UV exposure. Moreover, UVC is filtered by
the ozone layer and is not present in nature on the earth surface.
Thus these organisms may lack the capability to repair damage to
their genetic materials caused by exposure to UVC and may also be
more sensitive than most bacteria.
[0076] These reasons also apply to the treatment of skin
infections. However, it is the treatment of nail infections that is
a particular problem since it is very difficult to treat such
infections with the nail shielding the organisms which cause the
infections.
Overview of UV Light
[0077] Ultraviolet light has a shorter wavelength than visible
light as can be seen in FIG. 1.
[0078] Ultraviolet light is commonly broken down into three ranges
labeled UVA (315 nm to 400 nm), UVB (280 nm to 315 nm), and UVC
(100 nm to 280 nm).
[0079] Another common division of UV light is Far UV (100 nm to 300
nm) and Near UV (300 to 400 nm). These ranges are graphically
illustrated in FIG. 2.
[0080] Each light range has different effects on skin and
organisms. UVA is the most commonly used light range for tanning.
It is also the wavelength use for `black lights` which fluoresce.
UVA is also a light range commonly used for phototherapy of
psoriasis in conjunction with photoactive agents.
[0081] UVB is considered the most destructive wavelength with
respect to the skin and also the most carcinogenic. The amount of
UVB emitted by tanning bulbs is regulated by the FDA due to its
carcinogenicity. Nevertheless, 308 nm light (in the high range of
the UVB range) has been successfully used to treat psoriasis. It
appears that this autoimmune disorder responds well to this
wavelength and its beneficial effect appears to outweigh its
potential carcinogenicity.
[0082] UVC is the shortest wavelength and it generally has the
least effect since it is easily absorbed and does not penetrate any
media well. Since it is absorbed by the air, none of the UVC light
emitted from the Sun reaches the surface of the earth. It does not
penetrate the skin deeply and it has not been used in the treatment
of skin disorders due to its low ability to penetrate the skin.
However, UVC has the most germicidal effect organisms. If these
organisms are suspended in the air or are on the surface of an
object, UVC light can be used to kill and inactivate them. Again,
due to its limited penetrability UVC has not been used to treat
skin and nail infections since it was assumed that enough light
would not penetrate to make treatment effective.
[0083] FIG. 3 shows the various depths that UV will penetrate the
skin. This figure is reproduced from the report titled Ultraviolet
Radiation (Environmental Health Criteria:160, published by the
World Health Organization in 1994. ISBN 92 4 157160 8. This report
is referenced in this report as `UV Radiation, 1994`). The figure
was numbered 4.1 in the text. This figure shows that while UVA
light penetrates deeply into the epidermis and dermis, UVB light
has much less ability to penetrate, and UVC can only penetrate part
of the epidermis. At a depth of 75 um, 20 times more UVA light at
365 nm penetrates than UVC at 254 nm. This is why UVC has not been
used to treat skin and nail infections.
[0084] However, low penetration is not the same as no penetration
and the invented treatment relies on the fact that even a small
amount of penetration can be used to successfully prevent and treat
infections. UVC is so well tolerated by the skin and nails that it
is possible to apply large enough doses that sufficient germicidal
light penetrates deeply enough to prevent and treat skin and nail
infections.
[0085] Germicidal light is a specific composition of matter
composed of photons vibrating at specific wavelengths. It is the
specific wavelengths of these photons that permit the light to
interact with the biomolecules in the genetic material of the
cells. During this interaction the light causes these biomolecules
to deform and crosslink in a manner that prevents the cells from
being able to replicate properly.
How UV Light Affects Cells and Organisms
[0086] As discussed in a UV text (UV Radiation, 1994), UV light
effects cells and organisms by a biomolecule as it absorbs a photon
and produces an excited state which elevates the energy level of
the absorbing molecule. The primary products of this interaction
are reactive species or free radicals. DNA is the most critical
target for damage by UVB and UVC radiation. While numerous types of
UV induced DNA damage have been observed, the most significant
reaction is the formation of cyclobutane-type pyramidine dimers as
shown in FIG. 4 (reproduced from FIG. 6.1, UV Radiation, 1994).
[0087] The formation of pyrimidine dimers is the most significant
form of UV induced damage to cells and organisms and occurs
primarily in the UVB and UVC ranges. It is especially strong in the
UVC range and peaks at 260 nm. FIG. 5 below (reproduced from FIG.
6.2, UV Radiation, 1994). This figure clearly illustrates that
outside the UVC and UVB range a significant amount of pyrimidine
dimers do not form. For example, it takes approximately 100,000
times the dose of UVA light at 320 nm to form a pyrimidine dimer
than it does with UVC light at 260 nm. This illustrates why UVC has
such a potent germicidal effect compared with other wavelengths of
light.
[0088] A second type of pyrimidine dimer formed by UV is the thy
(6-4) pyo photoproduct. This dimer also contributes to UVC's
ability to damage the DNA of an organism. FIG. 6 shows the
effectiveness of various wavelengths of light to form the 6-4
pyrimidine dimer.
[0089] Crosslinking of DNA prevents an organism or cell from
replicating properly. DNA is a double helix that `unzips` to
provide a template for the cell to reproduce. Crosslinking of the
DNA is analogous to a kink in a zipper that prevents it from
unzipping properly. When the DNA is unable to form a template due
to crosslinking the organism cannot reproduce properly and thus
cannot sustain an infection. This type of inactivation of an
organism by damaging its genetic material and preventing it from
reproducing will be defined antigenosis for the purposes of this
application. Processes that induce this antigenosis will be
referred to as `antigenotic.`
[0090] Because UV is absorbed by nucleic acids it also has the
ability to damage additional functions of a cell or organism.
Although this damage is less than that caused to DNA, if it is in
sufficient quantity it can inactivate or even kill an organism.
This damage is not caused by excessive heat but results from
additional radiation damage to the organism such as damage to the
RNA of an organism. Since RNA is used as a messenger within a cell,
its destruction will result in the cell being effectively destroyed
even before it eventually dies from damage to its DNA. Thus, in
addition to inactivating and organism by damaging its DNA with UV,
it is possible to destroy an organism with high doses of UV by
disrupting its cellular processes. It may take 10 to 100 times the
inactivation dose to actually kill the organism immediately instead
of just damaging its ability to reproduce, however, due to the low
heat generating ability of UV, this dose can be administered
without causing excessive heating. Destruction of an organism in
this way by damaging its genetic material and preventing it from
reproducing will be referred to as `geneticide.` It should be noted
that although damage to the genetic material of a cell is the major
cause of geneticide other processes can contribute to this process
which are not directly genetic such as destruction of mRNA and the
rupture of cell membranes.
Organism Destruction by Excessive Heat
[0091] Destruction by excessive heat is a different method used to
kill organisms than irradiation by UV. Excessive heating to kill
and organism relies on heat's ability to denature proteins in a
cell. Denaturing of proteins by excessive heat causes the
secondary, tertiary, or quaternary structure of proteins to unfold
so that the protein's original properties, especially their
biological activities, are diminished or eliminated. For example,
an enzyme when it is subjected to high levels of heat unfolds and
is no longer able to catalyze reactions. Destruction of an organism
in this manner by excessive heat will be referred to as thermocide.
A classic example of thermocide caused by the denaturing of protein
by excessive heat is the boiling of an egg. The heat causes the
protein albumin to denature and change from a clear liquid to a
white solid. This example also illustrates the generally
irreversible nature heat denaturization of protein since there is
nothing that can be done to the white of the egg to reverse the
process.
[0092] Most unicellular organisms contain in the range of 50%
protein and less than 5% DNA (for example E. coli contains about
55% protein and about 3% DNA). Destroying an organism by adding
excessive heat to denature proteins (thermocide) in general is thus
relatively easy if enough heat is added. This excessive heat will
effectively denature approximately half of the organism and this
massive destruction will effectively destroy the cell. Targeting
the destruction of the genetic material (geneticide) is a more
precise means of inactivating an organism.
Distinction Between Thermocide (Denaturization Caused by Excessive
Heat) and Geneticide (Destroying an Organism by Damaging Genetic
Material)
[0093] Thermocide or destruction by excessive heat relies on
denaturing proteins by applying large amounts of thermal energy
while geneticide uses UV to destroy an organism using precise
radiation to specifically target the genetic material of an
organism. Geneticide or destroying an organism by damaging its
genetic material can be accomplished by the use of UV irradiation
and does not generate excessive heat and therefore requires
significantly less thermal energy than thermocide.
[0094] For example, Lurie (U.S. Pat. No. 6,090,788, column 12, line
5) notes that yeast can be destroyed by applying excessive heat at
a dosage of 5 to 10 J/cm.sup.2 with a laser using 632 nm light.
However, the inactivation dose for 99.9% destruction of common
yeast is listed as approximately 0.01 J/cm.sup.2 in the
inactivation charts provided by Atlantic UV which is 500 times less
energy. It should also be noted that even at the same dosage of UV
there would be much less heating of the skin or nails since UVC at
254 nm only penetrates to 100 um while 632 nm light penetrates
10,000 um-100 times deeper. The greater depth of light penetration
of the 632 nm generates significantly more heat than 254 nm light
at the same energy. Thus the difference in heat generated to kill
yeast using a 632 nm laser is significantly more than 500 times
that generated to kill yeast using UVC light at 254 nm.
[0095] Damage of the genetic material of an organism can cause it
to die by apoptosis, which is a term generally used in biology and
is defined as the programmed death of an organism. Apoptosis occurs
when an organism sustains enough damage that it cannot continue to
function or it is damaged so that it cannot reproduce. When an
organism receives this amount of damage it self-initiates the
process of apoptosis which results in the ultimate disintegration
of the organism. Apoptosis is different from necrosis the latter
being a term generally used in biology and applied to a cell
destroyed by outside forces such as the application of excessive
heat. Irradiation of an organism can destroy an organism by both
apoptosis (causing damage to the genetic material of an organism
and causing it to initiate its own destruction) and by necrosis (by
overwhelming the cell by damaging its genetic material in a way
that it can no longer function effectively) while the addition of
excessive heat must rely solely on necrosis.
[0096] Several analogies that may serve to illustrate the
difference between destruction by excessive heat and destruction by
radiation damage due to UV more clearly are listed below: [0097]
Destroying an organism by geneticide using UV is analogous to
targeting a cell with a precise bullet (UVC radiation) instead of
using a napalm bomb to destroy it (thermocide or destruction by
excessive heat) [0098] Destroying an organism by geneticide using
UV is similar to sending in a special forces team to destroy a
specific installation (the genetic material of a cell) instead of
saturation bombing of an area (thermocide or destruction by
excessive heat).
Summary of Treatments of Infected Nails
[0099] Treatment can be illustrated by the application of the
invention to four infected nails. Germicidal light was generated
using a low pressure mercury lamp of which approximately 95% of its
light was emitted at a wavelength of 253.7 nm. This is illustrated
in FIG. 7.
[0100] The dosage of UVC light was conservatively applied in order
to ensure that the National Institute for Occupational Safety and
Health (NIOSH) guidelines for daily irradiation of skin were not
exceeded. The skin surrounding the nails was fully protected from
the UVC irradiation by shielding. Preliminary transmissivity
measurements on several healthy nails indicated that approximately
0.01% to 0.03% of UV 254 penetrates a healthy nail. Due to the
limited test data it was assumed that 0.05% of UV 254 penetrated
the nails. Total irradiation of the skin under the nail was limited
to less than 6 mj/cm.sup.2, the NIOSH standard for daily exposure.
However, it should be noted that this guideline is very
conservative and it is possible to treat infections using a much
higher dose without generating significant side effects.
Summary of Testing and Results of Treatment of Infected Nails
[0101] The table below summarizes the results of testing on four
nails tested:
TABLE-US-00001 Total Average Effective Dose per Total Dose (0.05%
Nail No. of Exposure Dose penetration) No. Exposures (mj/cm.sup.2)
(mj/cm.sup.2) (mj/cm.sup.2) Effect on nail 1 8 44.5 356 0.2
Complete Cure 2 7 319 2,233 1.1 Some Improvement 3 4 573 4,583 2.3
Moderate Improvement 4 4 573 4,583 2.3 Major Improvement
[0102] The success of treatment at the dosages of UV254
administered indicate that the organisms that cause onychomycosis
are more sensitive or have a similar sensitivity to UV254 as
bacteria, many of which exhibit two log (99%) inactivation in the
range of 1 to 12 mj/cm.sup.2.
[0103] A brief summary of each nail, irradiations, and the results
of irradiation is included below.
[0104] Nail 1--Large toe nail had an aggressive fungal infection
that spread rapidly. Nail was treated in several sessions over
three months. Nail grew out clear. However, after one year there
may have been a recurrence of the infection. Nail was treated again
and grew out clear.
[0105] Nail 2--Large toe nail had moderate to severe onychomycosis.
Nail had been removed several years earlier. However, the nail
regrew and the infection was reestablished causing pain when shoes
were worn. The nail showed moderate improvement and the pain
associated with the infection was alleviated. However, the nail did
not fully clear nine months after treatment.
[0106] Nail 3--Large toe nail had severe onychomycosis with erosion
of skin at base of nail. Nail had been removed several times and
person had used two different types of oral medications (at a cost
of more than $1,000) with no improvement. Person had not used
medication for fungal infection for several years before treatment.
Less than three months after treatment the nail showed significant
improvement. The skin at the base of the nail has regrown and new
nail at the base of the nail is growing in much clearer. Most of
the dark material under the nail has been eradicated.
[0107] Nail 4--Large toe nail had severe onychomycosis. Nail had
been removed several times and person had used two different types
of oral medications (at a cost of more than $1,000) with no
improvement. The person had not used any medication for fungal
infections for several years prior to irradiation. Less than three
months after irradiation the nail shows significant improvement.
After one year, the base of the nail is growing in almost clear and
most of the dark areas under the nail are eradicated.
Discussion of Treatment
[0108] Results have been exceptional given the limited amount of
data and the conservative application of germicidal light used
during treatment. When the first two nails were treated it was
assumed that 10% of the germicidal light penetrated the nail.
Subsequent discussions and literature search indicated that this
was too high and a value of 2% was used. Later preliminary testing
with a UV meter indicated that actual light penetration was between
0.01 and 0.03%. Therefore, the amount of light used to treat nails
4 and 5 was increased.
[0109] Summary--Of the four nails treated, one of the nails
exhibited complete cure, one nail has exhibited moderate
improvement, and two nails have shown very significant improvement
but have small areas which require additional treatment. Given that
fungal infections do not clear by themselves and the difficulty in
establishing the exact dose necessary for complete inactivation of
an organism the initial results indicate significant efficacy. The
data also suggest that a higher dose of light at 254 nm can be
easily tolerated and would improve the efficacy of the treatment.
It is estimated that doses of 10 to 20 J may be easily tolerated
and that a series of 6 to 12 such treatments would cure a majority
of nail infections. Since the nail itself is composed of dead
keratin it is also possible that much higher doses of UVC light may
be applied to the nails on the order of 100 J or more without
significantly affecting the person being treated.
Illustrations of Treatment of Skin and Nail Infections
[0110] FIG. 7 shows the invention being used to treat a nail
infection such as an infection caused by a dermaphyte such as T.
rubrum. The invention may also be used to treat a nail disorder
such as psoriasis of the nail.
[0111] FIG. 8 shows the invention being used to treat a skin
infection such as an outbreak of acne caused by acne vulgaris.
[0112] FIG. 9 shows the invention being used to prevent a nail
infection by irradiating the nail and killing any organisms before
they can establish an infection.
[0113] FIG. 10 shows the invention being used to prevent a skin
infection such as athletes foot by irradiating the skin and killing
any organisms before they can establish an infection.
FIG. 11 illustrates a device to prevent and treat skin and nail
infections. FIG. 12 illustrates special attachments for use with
the treatment device.
Description of Invention
[0114] The method for the prevention and treatment of skin and nail
infections combines the use of germicidal electromagnetic radiation
with the previously unrecognized ability of said radiation to
penetrate the nails and skin sufficiently to inactivate
organisms.
[0115] The following descriptions of the presently contemplated
best modes of practicing the invention is not to be taken in a
limiting sense, but is made merely for the purpose of describing
general principles of the invention. The scope of the invention
should be determined with reference to the claims.
[0116] As noted above, the present invention employs germicidal
radiation to prevent and treat skin and nail infections. To
successfully treat these infections it is necessary to provide
radiation that is germicidal in nature, is able to penetrate to the
site of the infection, and is delivered for sufficient time and
strength to inactivate the organism. Treatment is accomplished
using the previously unrecognized ability of germicidal radiation
to penetrate the skin and nails sufficiently to inactivate
organisms that cause skin and nail infections by antigenosis or by
geneticide. Also, although the description of the invention
discusses human subjects, it is contemplated that the treatment can
be used on both human and animal subjects.
[0117] Said method is capable of being used to treat and prevent
all infections of the skin and nails. This includes the most common
skin infections caused by Staphylococcus aureus, Streptococcus
pyrogenes, Psuedomonas aeriginosa, and all other organisms that
cause skin infections. It also includes nail infections caused by
bacteria, fungi (including dermaphytes, yeasts, molds, and
non-dermaphyte molds), viruses, and other microbes. Specifically,
organisms causing fungal infections of the nails, said infection
being termed onychomycosis, are included in the list of organisms
treated by this invention.
UVC
[0118] The most recognized form of germicidal radiation is UVC
radiation in the range of 240 to 280 nm. Radiation in this range is
absorbed by the RNA and DNA of a cell and damages the ability of
the cell to reproduce. Other forms of radiation have also been
found to inactivate organisms including sources at 180 to 1370 nm
and sources that emit in a high intensity pulsed manner. Although
the applicant does not wish to be bound by any theory of operation
it is believed that major effect of germicidal light is to damage
an organism's genetic material so that it cannot reproduce or by
damaging the cell so that it cannot survive and reproduce.
[0119] It has been observed that organisms vary in their resistance
to the effects of germicidal radiation. For most organisms a dose
of 5 to 10,000 mw-sec/cm.sup.2 (5 mJ/cm.sup.2 to 10 J/cm.sup.2) is
sufficient to completely inactivate an organism. This dose may be
applied in several separate sessions, however, care must be taken
that the organism does not recover and reinfest the area between
treatments.
[0120] Preferentially, the radiation of choice is UVC is the range
of 254 nm that can be readily produced by a low pressure mercury
lamp or by a laser. This type of radiation source (generally a
mercury lamp) is readily available from a number of manufacturers
and there is an extensive list of inactivation doses for many
organisms for this type of light. This type of radiation is the
preferred form of radiation for disinfection of air in buildings
such as hospitals and for disinfection of drinking water. A laser
with output at approximately 254 nm is another preferred source of
radiation. A laser could be more effective that a low pressure
mercury lamp since it can precisely deliver a specified dose or
radiation without affecting adjacent areas. This type of laser is
currently commercially available and is used for manufacturing
integrated circuits among other things. A medium pressure or high
pressure mercury lamp are other preferred sources of germicidal
radiation since they emit strongly in the UVC range while also
containing other light ranges that are known to be germicidal such
as UVB light. Xenon lamps also emit a significant portion of their
light in the germicidal range and their non-germicidal component
appears to work synergistically to reduce the amount of light
needed to inactivate organisms.
[0121] It is possible to treat a nail or skin infection using
radiation without knowing what organism causes the infection.
However, doing so runs the risk of not applying sufficient
radiation or conversely applying too much radiation. Therefore,
when treating an infection it is best to make a diagnosis of what
organism is causing the infection. Once the cause of the infection
is determined, the practitioner can consult the UVC charts that are
available from the manufacturers of UV germicidal lamps. Many
charts list have more than 50 different types of organisms listed
along with the dose of UV at 254 nm that is required to inactivate
them. Charts are available from the American Ultraviolet Company
(Murray Hill, N.J.), from the Atlantic Ultraviolet Corporation
(Hauppauge, N.Y.), other manufacturers, and research organizations.
The inactivation charts provided by American Ultraviolet Company
and Atlantic Ultraviolet Corporation are incorporated by reference
as if fully set forth herein.
[0122] Once the infection causing organism is determined and the
necessary UV dose at 254 nm is obtained from a chart, a
practitioner must determine the distance from the skin the lamp
must be held and the amount of time the area should be irradiated
to deliver the necessary dose. Manufacturers of germicidal lamps
provide formulas to determine these parameters.
Example of Treating a Skin Infection
[0123] To treat a skin infection a practitioner would generally:
[0124] 1. Determine the cause of the infection if possible [0125]
2. Determine the dose of germicidal radiation necessary to treat
the infection taking into account the attenuation of the light as
it penetrates [0126] 3. Determine how to apply the dose or doses of
radiation [0127] 4. Apply the dose or doses of radiation [0128] 5.
Follow-up after treatment to determine if the infection has been
stopped [0129] 6. Provide additional treatment as necessary
[0130] Step 1--Determine the cause of infection--To determine the
cause of infection, a practitioner would either culture the
organism from a sample or would make a clinical determination based
on visual observations. If a definitive determination is not
possible the practitioner would choose the most likely organism
that requires a high inactivation dose in order to be sure that
enough radiation was applied.
[0131] Step 2--Determine the dose of germicidal radiation--Next a
practitioner would determine the dose of germicidal radiation
necessary. Inactivation doses are available in charts for many of
the organisms that cause skin infections such as Staphylococcus
aureus (6,600 uw-sec/cm.sup.2 to inactivate), Streptococcus
pyrogenes (4,200 uw-sec/cm.sup.2 to inactivate), and Psuedomonas
aeriginosa (10,500 uw-sec/cm.sup.2 to inactivate). Additionally,
new organisms are being added all the time as more research is
directed to the germicidal effects of UVC light. If an organism is
not listed on the chart it may be possible to infer a probable
inactivation dose. For example, of the more than 50 types of
bacteria listed on one manufacturer's chart, all the inactivation
doses ranged from 2,500 to 26,400 uw/cm.sup.2 (with the exception
of Anthrax spores which are especially difficult to treat and have
a published range of 9,400 to 135,000 uw/cm.sup.2 to inactivate).
Therefore, if a person had a bacterial infection and it was not
possible to determine its cause, a practitioner could irradiate the
infection at the high end of the range to inactivate the infection.
As germicidal treatment of infections becomes more common it is
expected that the inactivation doses of all major organisms will be
determined with greater accuracy and more definitive doses can be
determined.
[0132] Skin infections are often difficult to treat due to
encrustations and debris and due to the sensitivity of the area.
While germicidal radiation is attenuated by encrustations and
debris the radiation, if applied in the proper dose, enough should
be able to penetrate sufficiently to have a beneficial effect.
However, good practice would dictate that as much as possible all
encrustations and debris be removed to maximize the benefits of the
radiation. It may also be necessary to spread out treatments in
particularly deep infections so that the surface of the infection
may heal and permit easier application of radiation to the deeper
levels (clear skin will permit radiation to pass more easily than
thick and opaque encrustations. It may also be desirable to use a
high powered tunable laser to provide precisely targeted UV to more
recalcitrant infections.
[0133] The actual transmissivity of the light through the skin and
the infection must also be taken into account to determine the
proper dose. Since germicidal light is easily absorbed by the skin
and any obstruction of caused by the infection, an assumed
transmissivity rate of 1% is prudent unless the practitioner has
more definitive information available. Thus if a practitioner
determined that the infection was caused by Staphylococcus aureus
(a common cause of skin infections) he could then consult a chart
and determine the inactivation dose was 6,600 uw-sec/cm.sup.2.
Assuming a transmissivity rate of 1% and applying a factor of
safety of 2 the practitioner would then need to apply 1,320,000
uw-sec/cm.sup.2 to treat the infection.
[0134] Step 3--Determine how to apply the dose of radiation--If a
practitioner determined that the infection was caused by
Staphylococcus aureus and desired to apply a total dose of
1,320,000 uw-sec/cm.sup.2 to treat the infection this could be
achieved using a G6T5 low pressure lamp available from American
Ultraviolet Company (AUC). The lamp uses fixtures and ballasts that
are similar to fluorescent lights. The lamp provides 11 uw/cm.sup.2
at a distance of one meter. If the lamp is held 6-inches from the
infection the multiplication factor to convert the applied
radiation 1-meter to the amount applied at 6-inches is obtained
from a chart supplied by American Ultraviolet Company. This factor
is 12. Therefore a G6T5 lamp held 6-inches from an infection will
irradiate 132 uw/cm.sup.2 (11 uw/cm.sup.2 times the conversion
factor of 12). Thus, a practitioner would need to irradiate a
person for 10,000 seconds (1,320,000 uw-sec/cm.sup.2 divided by 132
uw/cm.sup.2) at a distance of 6-inches from the infection to
inactivate an organism. Thus the total irradiation would be 167
minutes (10,000 seconds) and it may be desirable to apply the UVC
in several doses in order to minimize the amount of UVC in each
dose. This would also permit the first dose to kill the organisms
closest to the surface and provide time to clean the infection of
the dead organisms and retreat the infection. The depth of
effective treatment would thus be greatly increased
[0135] Step 4--Apply the radiation--Continuing with the example,
the total dose of 167 minutes could be applied in three consecutive
daily sessions of 56 minutes each and prior to each irradiation the
infection could be cleaned to remove debris and any organisms that
might have been destroyed by prior irradiations. A device similar
to that shown in FIG. 11 may be used to administer the
radiation.
[0136] Step 5--Follow-up after treatment--Once the radiation has
been applied, the practitioner would schedule regular follow-up
appointments to monitor the status of the infection. If the
infection continued to spread, the practitioner would apply
additional doses of radiation to inactivate the organism causing
infection.
[0137] Step 6--Provide additional treatment as necessary--It is
possible that the original treatment of the infection may not
completely cure the infection due to a number of factors such as
lower penetration of light than anticipated. If the infection has
not totally cleared the practitioner would estimate the amount of
clearing and apply additional treatments to provide complete
eradication of the infection. For example, if only 50% of the
infection had appeared to clear the practitioner may decide to
apply 200% of the radiation originally applied to take into account
that the remaining infection may be twice approximately twice as
resistant as the half that was originally eradicated.
Treatment of Skin, Teeth, and Membranes of the Mouth
[0138] The same procedures used to treat skin could be used to
treat the skin, teeth and membranes of the mouth although special
care must be taken to prevent damage to these sensitive areas.
[0139] Germicidal light could be used to treat infections such as
cold sores of the mouth caused by the Herpes virus.
[0140] Germicidal light could also be used on a periodic basis for
by persons infected with the HIV or Aids virus to lower the virus
counts in their saliva. This may have an overall positive effect on
the health of the person and would also decrease the infectiousness
of the saliva.
[0141] Germicidal light could also be used to prevent and treat
dental caries. This would be especially effective once the teeth
were cleaned of all plaque and the light could be easily delivered
to the surface of the teeth and gums.
[0142] Special devices similar to those shown in FIG. 12 can be
used to deliver light in the confined space of the oral cavity. One
device would be an oral insert similar to a mouth guard that would
form around the teeth. The insert could come in preformed sizes for
a variety of mouth shapes or it could be specially formed for the
person being treated. The insert would be made of a materially that
is optically transparent to germicidal light such as fused quartz
or Teflon and which could also diffuse the light evenly over the
area being treated. The device could then be used to irradiate the
inside of the mouth in a relatively uniform manner. Another special
device could be used to deliver germicidal to a point in order to
treat a specific cold sore or a specific cavity. The germicidal
light could be delivered via a flexible wand which designed to
transmit germicidal light.
[0143] Example of Treating a Nail Infection
Use of UVC (200 nm to 280 nm)
[0144] Treating a nail infection is similar to treating a skin
infection with added attention to one item in particular. When
treating a nail infection, special account must be taken of the
transmissivity of the nail since its transmissivity is so low.
[0145] While it would be best to obtain a sample of the nail to be
treated and determine its transmissivity it may be possible to
extrapolate transmissivity from data collected on other nails.
[0146] For example, the transmissivity of UVC at 254 nm through
nails was measured using an IL1771 research grade radiometer. The
data indicate that nails have a range of transmissivity for UVC at
254 nm of approximately 0.01% to 0.001%. In the absence of actual
data it may be possible to approximate nail transmissivity as 0.05%
to conservatively calculate the lowest theoretical effective
dose.
[0147] Continuing the example, if it was determined that the nail
could only transmit 0.05% of light at 254 nm and the organism
required a dose of 9,000 uw-sec/cm.sup.2 then at total of 2,000
times that amount of energy, or 18,000,000 uw-sec/cm.sup.2 (18
Joules/cm.sup.2) would need to be applied to inactivate the
organism. A factor of safety would also need to be applied similar
to that for skin infections. Therefore, a dose of approximately 36
Joules/cm.sup.2 would be appropriate if a factor of safety of two
was applied.
Use of UVB (280 nm to 315 nm)
[0148] It is important that the transmissivity for the wavelength
of treatment be taken into account. For example, if nail treatment
were to involve the use of UVB light at 313 nm, it would be
necessary to determine or estimate the transmissivity of light at
that wavelength specifically. Light penetration for this wavelength
of light may be estimated from FIG. 3 to be approximately 10 times
greater than light at 254 nm. Therefore, in the absence of actual
nail transmittance data it may be estimated to be approximately
0.5% or ten times the value used for UVC 254 nm light.
[0149] The relative germicidal efficiency of UVB must also be taken
into account along with transmissivity. Light at 313 nm has
approximately 1/1000 the germicidal effectiveness of light at 254
nm.
[0150] Therefore, although ten times more light may penetrate the
nail, the dose would still have to be increased 100 fold (1000
divided by 10) to achieve approximately the same germicidal
ability. For example, if it was determined that the nail could only
transmit 0.05 percent of light at 254 nm and the organism required
a dose of 9,000 uw-sec/cm.sup.2 to inactivate, a total of 200,000
times that amount of energy, or 1,800,000,000 uw-sec/cm.sup.2
(1,800 Joules/cm.sup.2) would need to be applied to inactivate the
organism. This dose would probably be impracticable to apply
without thermal injury to the patient and illustrates why UVB is
not generally considered germicidal in and of itself.
[0151] It should be noted that while UVB at 313 nm is not
particularly germicidal, light in the lower UVB range, say around
280 to 290 nm is almost as germicidal as some UVC light. Thus light
in the lower part of the UVB range could be used by itself to
successfully treat skin and nail infections.
Use of UVA (315 nm to 400 nm)
[0152] Use of UVA light to inactivate organisms is also possible;
however, it has a much less potent germicidal effect. For example,
UVA light at 340 nm has approximately the same germicidal strength
as UVB light at 313 nm but it should be able to penetrate the nail
better. Thus it may be possible to use a lower dose of UVA at 340
nm than UVB at 3133 nm. However, even if the dose was decreased by
half it would still be too high to apply to the nails without
generating significant side effects such as a major sun burn. Thus
while UVA light may be used in conjunction with other germicidal
light it is not an ideal source by itself.
[0153] While UVA (315 nm to 400 nm) is not normally considered
germicidal by itself it is possible to modify the environment to
enhance UVA's ability to act germicidally on organisms causing skin
and nail infections. Modifications that enhance UVA's germicidal
capabilities include the addition of a high ionic strength solution
(such as saline), increasing the pH, and increasing the oxygen
content (by adding peroxide or other high oxygen content solution
or by directly applying a small amount liquid oxygen to a infected
area). The mechanism of organism destruction is different than that
of germicidal light in the UVC or UVB range since UVA in the
modified environment acts to disrupt cell membranes instead of
damaging its genetic material. Modifying the environment in this
manner thus permits the use of UVA light to treat skin and nail
infections.
Use of Medium Pressure Mercury Lamp
[0154] Light generated from a medium pressure mercury lamp has an
abundance of germicidal light in the UVC and UVB range. This type
of light is beginning to be more commonly used to disinfect
drinking water and wastewater and its characteristics is the
subject of greater study. The variety of germicidal wavelengths
present may also work synergistically together thus requiring a
lower overall dose to successfully treat a nail infection. Also,
the spread of the wavelengths of light through the nail may also
reduce any heat that might be generated by the treatment. To use
this type of light successfully it is necessary to estimate the
overall dose to inactivate an organism as well as the
wavelength-weighted transmissivity of the nail to this broad band
light source.
Use of Other Types of Germicidal Light
[0155] The description of the invention focuses UVC light to
prevent and treat infections. However, any electromagnetic
radiation that has antimicrobial effects is also contemplated by
this method to treat infections.
[0156] Germicidal light combining a continuum of germicidal
wavelengths and other wavelengths generally considered
non-germicidal is another possible treatment method for nail
infections. Varying the mode of application (i.e. pulsing, etc.)
may also increase the efficacy of such light. Specifically, light
generated from a Xenon lamp has an abundance of germicidal light in
the UVC and UVB range as well as light in other bands that seem to
work synergistically together thus requiring a lower overall dose
to successfully inactivate an organism. This type of light is
beginning to be used in water and wastewater treatment. It is also
being used in food processing. It has the potential to be more
effective than even pure germicidal light in the UVC range since
its synergistic effect often can inactivate an organism at a
significantly lower dose. Another advantage with respect to the
treatment of nails is that this type of light employs a variety of
wavelengths of light and the longer wavelengths can penetrate the
nails much more easily than UVC. While the longer wavelengths of
light are not considered germicidal by themselves they can act
synergistically with germicidal light to inactivate an organism.
Thus this type of light can be used particularly effectively to
treat skin and nail infections due to its greater ability to
penetrate.
[0157] An example of electromagnetic radiation other than UVC that
can be used to inactivate organisms is broad spectrum, high
intensity, pulsed light. Page 5 of Kinetics of Microbial
Inactivation for Alternative Food Processing Technologies (U.S.
Food and Drug Administration Center for Food Safety and Applied
Nutrition, Jun. 2, 2000) notes that a single pulse of such light
(with a wavelength of 170 to 2600 nm) with an intensity as small as
1.25 J/cm.sup.2 is sufficient to inactivate Staphylococcus aureus.
This is significantly less that the 6.6 J/cm.sup.2 of UV at 254 nm
required and makes the use of this type of radiation particularly
attractive. This type of light may also penetrate more easily
(longer wavelength light penetrates more easily than short
wavelength light) and is better tolerated than UVC which is also
advantageous. This type of light is an excellent example of how
other wavelengths of light can be synergistically combined with UVC
germicidal light to enhance treatment of infections.
[0158] PurePulse Technologies, Inc. sells a pulse light that can
deliver this type of radiation under the trademark PUREBRIGHT.TM..
This type of light generally has a DC power supply which charges
capacitors, a switch which controls the discharge of the
capacitors, a trigger circuit which permits the capacitors to be
discharge at preprogrammed time intervals, a manual discharge mode,
and one to four flash lamps mounted in reflectors to direct the
light emitted from the lamps. This configuration could be modified
and refined to be more suitable for use treating skin and nail
infections. The method to use this device would be similar to that
described above for using a low-pressure mercury lamp that is
described above. Research is currently being conducted on a wide
range of organisms to determine the energy necessary to inactivate
each organism and what is the best way to apply such energy (i.e.
one large pulse or a number of smaller pulses).
[0159] The effectiveness of multi-spectrum germicidal light for
inactivation of organisms at lower overall doses than UVC alone
indicates that other parts of the spectrum have germicidal
properties. The exact inactivation mechanism is not known, however,
it probably is a combination of several mechanisms that act
together to render the cell inactivated or incapable of
reproducing. Although the author does not wish to be bound as to
the mechanism of inactivation used, several observations may be
made. In addition to probable damage to the organism's genetic
material, the multi-spectrum light could damage other components of
the organism necessary to its vital functions. It may also provide
instantaneous heating of small areas in the cell which would not
kill the organism by high heat but which are nonetheless effective
in damaging the cell wall and inactivating the organism.
[0160] It is likely that there are certain types of radiation that
are more effective than others at inactivating organisms or
preventing them from reproducing. These types of radiation are
likely contained in the range of pulsed light (170 to 2600 nm) but
other parts of the spectrum may also be germicidal. Therefore, the
proposed method to prevent and treat skin and nail infections
encompasses any forms of electromagnetic radiation that can be used
germicidally to inactivate an organism or prevent it from
reproducing.
Prevention of Skin and Nail Infections
[0161] Additionally, microbial infections can be prevented by the
periodic application of electromagnetic radiation to prevent
incipient infections from occurring. This would be particularly
desirable in populations prone to fungal infections (such as
diabetics and the elderly) and those who require constant
monitoring (such as those in hospitals and nursing homes). It would
also be very desirable for those whose health could be
significantly threatened by a fungal infection (such as diabetics
or immunocompromised individuals). Fungal infections of the nails
in a diabetic person can progress and associated complications can
lead to amputation of a finger or toe. The dose necessary to
prevent fungal infections would be significantly less than that
necessary to eradicate a full blown infection. The dose would be
approximately in the range of half of the standard dose and should
be sufficient to inactivate approximately 99% of the organisms that
may be present. This dose would be applied on a periodic basis
(daily, weekly, monthly, or quarterly depending on the estimated
risk of infection and the dose applied) to help keep a person
infection free.
[0162] FIG. 9 is an illustration of germicidal light being used to
prevent a nail infection such as onychomycosis.
[0163] FIG. 10 is an illustration of germicidal light being used to
prevent a skin infection such as athletes foot.
[0164] FIG. 11 is an illustration of a device that can be used to
prevent skin and nail infections. FIG. 12 is an illustration of
special attachments that may be used with the device to treat skin
and nail infections.
[0165] The foregoing is illustrative of the present invention and
is not to be construed to be limiting thereof. Although a few
exemplary embodiments of this invention have been described, those
skilled in the art will readily appreciate that many modifications
are possible in the exemplary embodiments without materially
departing from the novel teachings and advantages of this
invention.
Enhancement of Treatment
[0166] There are a number of ways that treatment by germicidal
radiation may be enhanced. These enhancements are discussed further
in this section
Creation of an Unfavorable Environment
[0167] It has been shown that organisms are less resistant to
germicidal radiation of they are subject to environmental stresses.
Creation of an unfavorable environment is therefore one way to
enhance treatment with germicidal radiation. Deprivation of food
and nutrients, unfavorable temperature regimes, varying of pH, etc.
are all techniques that may be used to enhance the effectiveness of
treatment using germicidal light. Thus the invention may be
supplemented by the creation of unfavorable environmental
conditions for the organisms.
These enhancements are therefore included as part of this
invention.
Change of Skin or Nail Characteristics
[0168] Germicidal light has very low penetration power. Therefore,
any modification of skin or nail characteristics to enhance
penetration would have a significant beneficial effect on treatment
effectiveness. For skin this may include the application of
preparations that change the characteristics of the epidermis to
permit greater penetration of germicidal penetration. It may also
include the treatment of any skin abnormalities such as calluses or
scabs to remove obstacles to penetration by germicidal light. For
nails this would include compounds that may enhance the
transmission of light through the nails. It would also include
partial or total removal of the nail (perhaps through the
application of urea or a similar compound) to permit better
penetration of the germicidal light to the site of the
infection.
[0169] These enhancements are therefore included as part of this
invention
Enhancement Via Use of Media to Transmit Light
[0170] The application of germicidal radiation could be enhanced by
the use of a media to transmit the light effectively. The media may
be a special gas, liquid, or solid which can maximize the
application of light to the affected area or prevent it from being
applied in undesirable areas. A form of application could be a gel
applied to the infected area which permit the light unit to be
place in contact with the gel or perhaps just focused on the
gel.
[0171] These enhancements are therefore included as part of this
invention.
Use of Antibiotics
[0172] Topical antibiotics have been shown to have only a minimal
effect. For example Penlac, the leading topically applied
antibiotic, has less than a 12% total cure rate when applied daily
basis for more than 8 months. However, topical antibiotics can be
used to enhance treatment using germicidal lights. Similarly,
topical antibiotics could be used synergistically with germicidal
light to treat skin infections.
[0173] Systemic antibiotics also have limited effect on nail
infections. For example, LAMISIL.TM., the leading systemic
antibiotic for nail infections has only a 40% total cure rate for
nail infections. However, systemic antibiotics could be used
synergistically with germicidal light to greatly enhance their
effectiveness.
[0174] These enhancements are therefore included as part of this
invention.
Use of Other Light Spectrums Acting Synergistically
[0175] While the UVC, and UVB to a lesser extent, range of light is
the most potent germicidally, other parts of the light spectrum may
be used to further enhance the effectiveness of treatment. It is
well known that multiple stresses on an organism are more likely to
damage it. Thus, other parts of the light spectrum may be used to
create added stress on the organisms and cause them to be
inactivated successfully using lower doses of germicidal light. For
example, longer wavelengths of light generate heat which although
it may not be sufficient to kill an organism by itself could be
used in conjunction with germicidal light to successfully treat an
infection.
[0176] This synergistic action can be seen in the use of Xenon and
other broad spectrum lamps that have been used to disinfect air and
water. The synergistic action of the light spectrums greatly
enhances the germicidal ability of light.
[0177] These enhancements are therefore included as part of this
invention.
Use of Lasers
[0178] Lasers have a number of characteristics that make them
particularly useful in treating skin and nail infections using
germicidal light.
[0179] First, some lasers (e.g. tunable lasers) have the ability to
be tuned to a very precise point of the light spectrum thus
permitting the most effective wavelength to be applied to an
infected area.
[0180] Second, it is possible to tightly focus a laser and thus
precisely apply energy where needed. This permits treatment of the
infected area only without involving any non infected area. For
example, it is possible to treat nail infections without affecting
the surrounding skin at all. Also, it is possible to tailor the
amount of energy applied to different parts of an infection. It is
thus possible to map an infection precisely and determine if more
germicidal radiation should be applied in some areas of the
infection.
[0181] Third, lasers tend to have higher power output than other
types of light sources making the application of high energy levels
extremely efficient.
[0182] Lasers also can be pulsed which may assist in their ability
to penetrate more deeply. It may also be possible that the coherent
nature of the light in a laser may permit it to penetrate more
deeply in certain mediums.
[0183] Within the range of 240 nm to 280 nm, it appears that the
primary mechanism is due to deformation of the organisms DNA.
Literature indicates that light in the range of 257 to 260 nm may
be most effective for most organisms; however, different organisms
have shown various sensitivities to different parts of the UVC
spectral region. There are several tunable lasers on the market at
the present time that could be used to treat infections with this
specific wavelength (such as the PAL laser manufactured by Light
Age, Inc.).
[0184] Excimer lasers are also possible devices that can be used.
Argon Fluoride at 193 nm, Krypton Fluoride at 248 nm, and Xenon
Chloride at 308 nm have all been shown to have some germicidal
ability. However, of the excimer laser Krypton Fluoride at 248 nm
has been show to be most germicidal, followed by Argon Fluoride at
193 nm, and lastly Xenon Chloride at 308 nm. GAM lasers
manufactures different types of excimer lasers which may be
suitable for these applications. Also, a frequency tripled
Ti:sapphire laser could be used since it deliver energy at 254 nm
or 280 nm. The foregoing list is intended to be illustrative and
not a comprehensive list of lasers that could be used.
[0185] Lasers can be used to generate significantly higher dosages
than may be easily generated by other forms of light. If extremely
high dosages of light are used it may be desirable to cool the skin
by use of water or by spraying a cryogen to cool the skin. Use of
cooling would be much more effective than when used for other
longer wavelengths of light since much less heat is generated in
the first place and all such heat will be on the surface of the
skin while longer wavelength light heats the lower layers of
skin.
[0186] These enhancements are therefore included as part of this
invention.
[0187] Description of Device to Prevent and Treat Skin and Nail
Infections
[0188] The treatment device may have any combination of the
following components: [0189] Light Source (10) that can be tuned to
a specified spectral output or a fixed spectral output. [0190] A
timer (12) [0191] A means (14) to determine the intensity of the
light [0192] A processing unit (16) that can perform calculations,
store data, track usage, troubleshoot problems, etc. [0193] A
camera (18) to take pictures [0194] A shield (20) to prevent light
from illuminating other areas [0195] Safety Labels (22) [0196]
Ground fault protector (24) [0197] Safe Operating Instructions (26)
[0198] Security devices (28) [0199] A connection (30) for special
attachments
[0200] FIG. 12 illustrates some of the special attachments that
could be used for treatment and includes the following: [0201] An
attachment (40) that can provide light to hard to reach areas such
as those between the toes. [0202] An attachment that transmits
light via a flexible cable (50) and delivers this light at the end
of the cable (52) to treat a specific area. [0203] An attachment
that can be inserted in the mouth (60) and can receive light from a
flexible cable (62) that can transmit such light.
[0204] Preferably, a treatment device is provided to prevent and
treat skin and nail infections incorporating the light source, and
which can incorporate a number of special features to enhance
treatment and promote safety. Such a treatment device is shown in
FIG. 11.
[0205] For example the treatment device may contain a light source
(10) that can be tuned to a specific spectral output or has a fixed
spectral output. This can be accomplished by the use of a tunable
laser, multiple lamps, or by the use of one or more filters to
screen out wavelengths that are not desirable. The treatment device
may also contain very small lamps capable of being inserted in
small spaces or directly on the surface to be treated.
[0206] Preferably, the treatment device can have a timer (12) and a
means (14) to determine the intensity of the light being provided
such as a spectrometer or radiometer. The device can also have a
processing unit (16) that can take the time of radiation and the
intensity and determine the dosage of light applied. The device can
also be programmed to take into account the transmissivity of the
nails being treated, if it were being used to treat nails. The user
of the device can then input the desired dosage of light to be
applied and the device can then accurately deliver it.
[0207] The treatment device can also have a number of additional
features which can be used separately or in various combinations
that make it easy to track the use of the device. The device can
use the processing unit (16) to retain a memory of each usage
session including how long the session was, the intensity of light
supplied, and the overall dosage applied during the session. It
would preferably have means for the operator to add an identifier
of the patient being treated for future therapy use. The device may
also be equipped with a camera (18) to take photos of the treated
area. These photos could be stored with other treatment parameters
making it easy to track the course of treatment over several
sessions. The device may also accept a set of treatment sessions
and monitor the records and provide reminders of when the next
treatments should be undertaken.
[0208] The processing unit (16) of device may be equipped with a
computer which will permit diagnostic activities on the correct
functioning of the device such as monitoring the lamp output to
ensure it does not degrade below a certain specified output. The
computer can also interface with the Internet via a wired or
wireless connection and transmit all information to a remote
source. The connection can also be used by a technician to
troubleshoot the device remotely and determine the cause of any
problems.
[0209] The device to prevent and treat skin and nails infections
can also be equipped with a number of attachments that can be used
to apply germicidal light in hard to reach or sensitive areas. Some
of these attachments are illustrated in FIG. 12. For example, there
could be an attachment (40) that could be inserted between toes to
irradiate the area between toes that is especially vulnerable to
athlete feet infections. Another attachment (50) could be used to
apply light to a small area of the nail or skin by use of a
flexible wand that can transmit germicidal light to the end of the
wand (52). This could also be used to irradiate the area between
the toes. This type of wand could also be used to apply light to a
specific area of the mouth. Another special attachment (60) can be
an insert that fits around the teeth in the mouth similar to a
mouth guard used by athletes to prevent injuries or by persons who
grind their teeth at night. This type of attachment (60) can be
made of an optically transparent material and a material to diffuse
light to permit the germicidal light to be applied uniformly inside
the mouth. Light for the attachment (60) can be supplied from the
germicidal unit by use of a fiber optic cable (62) or other similar
means.
[0210] The device to prevent and treat skin and nail infections can
contain a number of safety features. For example the special
attachments (FIG. 12) to irradiate the area between toes could be
coated with a material such as Teflon which is easy to clean and
which would protect the person if the encase lamp was broken.
Another safety feature would be another type of attachment to treat
the areas between the toes that used a flexible wand to transmit
the light thus eliminated the need for a small lamp that can fit
between the toes.
[0211] Other safety features include the use of a shield to prevent
the light from illuminating other areas (20), safety labels (22), a
ground fault protector (24) in case of a short circuit, and an
optically transparent barrier to prevent accidental damage to the
lamp. A specific safety feature claimed is the instructions for
safe use of the device to be included with each device (26).
[0212] The device can also incorporate security devices (28) to
prevent unauthorized use. This can include a fingerprint reader,
password protection, or remote enablement where a person makes a
call to receive a valid operational code to permit the equipment's
use.
[0213] The device can also have a connection (30) for special
attachments so that light can be routed and supplied to these
attachments. One skilled in the art would recognize that although
these treatment device features have been describe in alternative
language, that the features can be used together, individually or
in any combination of features.
DESCRIPTION OF FURTHER PREFERRED EMBODIMENTS
[0214] Several of the preferred embodiments make use of light as a
specific composition of matter composed of photons at specific
wavelengths that interact with the biomolecules present in genetic
material of a cell. This specific composition of matter causes the
genetic material of the cell to be damaged and prevents the cell
from reproducing. This specific composition of matter can also be
used to overwhelm the cellular processes mediated by genetic
material thus killing the organism directly.
Further Embodiment
[0215] In a further preferred embodiment, the radiation is that
which is necessary to inactivate the organisms that cause
infections of the skin and nails. The radiation is a specific
composition of matter composed of photons at specific wavelengths
that interact with the biomolecules present in genetic material of
a cell. This specific composition of matter causes the genetic
material of the cell to be damaged and prevents the cell from
reproducing. In the preferred embodiment the organism may be
inactivated by disabling its ability to reproduce or it may destroy
the organism by overwhelming the genetic processes of the cell thus
causing its death directly.
[0216] In a preferred embodiment of the invention the organisms
inactivated are those that cause infections of the skin and nails.
These organisms include bacteria, fungi (including dermaphytes,
yeasts, molds, and non-dermaphyte molds), viruses, and other
microbes. Specifically, organisms causing fungal infections of the
nails, said infection being termed onychomycosis, are included in
the list of organisms treated by this invention.
[0217] In a preferred embodiment, it may be necessary to irradiate
the skin and nails for several times in order to completely
inactivate the organisms in order to prevent and treat skin and
nail infections. The electromagnetic radiation in the preferred
embodiment consists of radiation in the UVC range (100 to 280 nm
and more specifically in the range of 240 to 280 nm) that is
capable of rapidly inactivating an organism. In a preferred
embodiment, the UVC source may be a low, medium, or high pressure
mercury vapor lamp or a laser.
[0218] In a preferred embodiment, the amount of irradiation
received during one treatment will be in the approximate range of 5
mJ/cm.sup.2 to 100 J/cm.sup.2. In a preferred embodiment it may be
desirable to apply the radiation in several sessions.
[0219] Another preferred embodiment of the method to prevent and
treat infections of the skin and nails involves irradiating the
infected area using a medium pressure or high pressure mercury lamp
which contains a variety of germicidal bands of lights. In a
preferred embodiment, the amount of irradiation received during one
treatment will in the approximate range of 5 mJ/cm.sup.2 to 100
J/cm.sup.2. In a preferred embodiment it may be desirable to apply
the radiation in several sessions.
[0220] Another preferred embodiment of the method to prevent and
treat infections of the skin and nails involves irradiating the
infected area using a lamp capable of generating light in the UVB
range between 280 and 315 nm. In a preferred embodiment, the amount
of irradiation received during one treatment will in the
approximate range of 50 mJ/cm.sup.2 to 100 J/cm.sup.2. In a
preferred embodiment it may be desirable to apply the radiation in
several sessions.
[0221] Another preferred embodiment of the method to prevent and
treat infections of the skin and nails involves irradiating the
infected area using a lamp capable of generating light in the UVA
range between 315 and 400 nm. In a preferred embodiment, the amount
of irradiation received during one treatment will in the
approximate range of 50 mJ/cm.sup.2 to 100 J/cm.sup.2. In a
preferred embodiment it may be desirable to apply the radiation in
several sessions. In the preferred embodiment it may be desirable
to modify the environment of the infection to enhance UVA's
germicidal capabilities include the addition of a high ionic
strength solution (such as saline), increasing the pH, and
increasing the oxygen content (by adding peroxide or other high
oxygen content solution or by directly applying a small amount
liquid oxygen to a infected area or by otherwise increasing the
oxygen content).
[0222] In an additional preferred embodiment the electromagnetic
radiation used may be from a polychromatic pulsed source such as
those used to disinfect food and instruments. In additional
preferred embodiments any electromagnetic radiation can be used
which is capable of inactivating the infection causing organisms,
is able to penetrate sufficiently, and is safe for exposure to
humans and animals in the doses contemplated. In a preferred
embodiment, the amount of irradiation received during one treatment
will in the approximate range of 5 mJ/cm.sup.2 to 500 J/cm.sup.2.
In a preferred embodiment it may be desirable to apply the
radiation in several sessions.
[0223] A preferred embodiment of a device to prevent and treat skin
and nail infections incorporates features to enhance treatment and
promote safety. The preferred device may have the power needed to
provide between 1 mJ/cm2 to 1000 J/cm2 or any range of power
therein.
[0224] The device may have the ability to provide light in a wide
range of wavelengths and it may have the ability to filter out
undesirable wavelengths. The device may contain a light source that
can be tuned to a specific spectral output accomplished by the use
of a tunable laser, multiple lamps, or by the use of one or more
filters to screen out wavelengths that are not desirable. The
treatment device may also contain very small lamps capable of being
inserted in small spaces or directly on the surface to be
treated.
[0225] The preferred treatment device can have a timer and a meter
to determine the intensity of the light being provided. The device
can also have a processing unit that can take the time of radiation
and the intensity and determine the dosage of light applied. The
device can also be programmed to take into account the
transmissivity of the nails if it were being used to treat
nails.
[0226] The treatment device can also have a number of features that
make it easy to track the use of the device. The device can have a
memory of each usage session including how long the session was,
the intensity of light supplied, and the overall dosage applied
during the session. The device can also be equipped with a camera
to take high resolution photos of the treated area. These photos
could be stored with other treatment parameters making it easy to
track the course of treatment over several sessions. The device can
also accept a set of treatment sessions and monitor the records and
provide reminders of when the next treatments should be
undertaken.
[0227] The device can be equipped with (or adapted to communicate
with) a computer or remote device which will permit diagnostic
activities on the correct functioning of the device such as
monitoring the lamp output to ensure it does not degrade below a
certain specified output. The computer can also interface with the
Internet via a wired or wireless connection and transmit all
information to a remote source. The connection can also be used by
a technician to troubleshoot the device remotely and determine the
cause of any problems.
[0228] The device to prevent and treat skin and nails infections
can also be equipped with a number of attachments that can be used
to apply germicidal light to hard to reach or sensitive areas. For
example, there could be an attachment that could be inserted
between toes to irradiate the area between toes that is especially
vulnerable to athlete feet infections. Another attachment could be
used to apply light to a small area of the nail or skin by use of a
flexible wand that can transmit germicidal light to the end of the
wand. This could also be used to irradiate the area between the
toes. This type of wand could also be used to apply light to a
specific area of the mouth. Another special attachment can be an
insert that fits around the teeth in the mouth similar to a mouth
guard used by athletes to prevent injuries or by persons who grind
their teeth at night. This type of attachment can be made of an
optically transparent material and a material to diffuse light to
permit the germicidal light to be applied uniformly inside the
mouth.
[0229] The device to prevent and treat skin and nail infections can
contain a number of safety features. For example the special
attachments to irradiate the area between toes could be coated with
a material such as Teflon which is easy to clean and which would
protect the person if the encased lamp were broken. Another safety
feature would be another type of attachment to treat the areas
between the toes that used a flexible wand to transmit the light
thus eliminated the need for a small lamp that can fit between the
toes.
[0230] Other safety features include the use of a shield to prevent
the light from illuminating other areas, safety labels, ground
fault protectors in case of a short circuit, and an optically
transparent barrier to prevent accidental damage to the lamp. A
specific safety feature claimed is the instructions for safe use of
the device to be included with each device.
[0231] The device can also incorporate security devices to prevent
unauthorized use. This can include a fingerprint reader, password
protection, or remote enablement where a person makes a call to
receive a valid operational code to permit the equipment's use.
[0232] The preferred embodiment of the treatment device may contain
any combination of the aforementioned features.
Other Preferred Embodiments
[0233] For particularly difficult infections, it is beneficial to
combine the said method of treatment with adjunct therapy including
the application of oral and topical medications. This combination
will work synergistically to effect a cure in a shorter period of
time, in a more complete manner, or in a manner that creates less
probability of relapse. Accordingly, a preferred embodiment is to
combine the said method of treatment with adjunct therapy including
the application of oral and topical medications as deemed
appropriate by those skilled in the field.
[0234] Use of UVA (315 nm to 400 nm) may also be employed to
inactivate organisms, particularly if the light is used in
conjunction with other types of germicidal light or the environment
modified to enhance the germicidal potency of UVA.
[0235] Use of additional wavelengths of light (similar to those
generated by a Xenon lamp) may also be used to synergistically
enhance the effect of germicidal irradiation. This is another
preferred embodiment.
[0236] It is well known that certain organisms can repair genetic
damage if they have access to certain wavelengths of light. This is
known as photoreactivation repair of genetic damage. Accordingly,
another preferred embodiment of the invention is to control the
environment of the skin or nail after treatment such that light is
not present thus preventing genetic damage from being repaired.
[0237] While some organisms use light to repair genetic damage,
other organisms are better able to repair genetic damage only if no
light is present. This is known as dark mediated repair of genetic
damage. Accordingly, another preferred embodiment of the invention
is to control the environment of the skin or nail after treatment
such that no light is present thus preventing genetic damage from
being repaired.
[0238] Other preferred embodiments of the invention rely on
creating a hostile environment that make the survival of the
organism more difficult to survive and thus work synergistically
with the germicidal radiation to kill the organism. For example,
most organisms causing fungal nail infections are aerobic. Thus, if
the source of oxygen was limited after treatment it would enhance
the inactivation dose of germicidal light. This could be
accomplished by application of a thick ointment (such as petroleum
jelly) or encasement of the nail in a membrane in which a
relatively inert gas (such as nitrogen) was present thus preventing
oxygen from reaching the organism.
[0239] Other preferred embodiments include means to enhance the
penetration of germicidal light. One such method would be the
application of urea to a nail to dissolve most of the nail and thus
expose the nail bed to direct radiation from the germicidal
light.
[0240] Other preferred embodiments include using germicidal light
to treat animals that have skin, nail, claw, or hair infections.
The germicidal light may also be applied to prevent such infections
also.
[0241] Other preferred embodiments may include dosages of 5
mJ/cm.sup.2 to 500 J/cm.sup.2 if the radiation is of a wavelength
that it can be applied safely in higher doses (this would be most
applicable if multi-spectrum light is used). The light may be of
multiple wavelengths and may be coherent or incoherent, and may be
pulsed.
FURTHER ALTERNATIVE EMBODIMENTS
[0242] The electromagnetic radiation in an alternative embodiment
may be from UVA radiation (315 to 400 nm).
[0243] The electromagnetic radiation in an alternative embodiment
may also be from the visible part of the spectrum.
[0244] The electromagnetic radiation in an alternative embodiment
may be from infrared radiation.
[0245] The electromagnetic radiation in an alternative embodiment
may be from radiation from a combination of visible and non-visible
parts of the light spectrum.
[0246] The electromagnetic radiation in an alternative embodiment
may be from a pulsed source including a xenon pulse source or a
laser.
[0247] The electromagnetic radiation in an alternative embodiment
may be incoherent or coherent such as a laser.
[0248] The electromagnetic radiation in an alternative embodiment
may be single spectrum or multi-spectrum.
[0249] In an alternate embodiment, the amount of irradiation
received during one treatment may be substantially more or less
than the 5 to 10,000 mw-sec/cm.sup.2 of the preferred embodiment.
In all circumstances the total amount of irradiation shall be
within the limits deemed safe by the medical community for
treatment of a disease or infection.
[0250] Accordingly, this invention can be used to prevent and treat
a wide variety of skin and nail infections. It has the following
advantages over the current method of treatments for these
infections: [0251] With respect to treatment using oral
medications, the invention eliminates unwanted and potentially
dangerous side effects (such as liver problems) that such
medications can cause. [0252] With respect to treatment using oral
medications, the invention uses a very small number of treatments
(one to perhaps a dozen) to eliminate the infection while
medications must be taken continuously for several months. [0253]
With respect to treatment using oral medications, the proposed
treatment has the potential to be significantly less expensive than
the current cost of $600 to $1200 for medicine. [0254] With respect
to treatment using oral medications, the infection can be
eliminated in much less time since the course of treatment would
vary from approximately one day to one month whereas the
medications must be taken from three to six months. [0255] With
respect to treatment by inducing a pigment and using a high energy
light to destroy an infection by excessive heat, the invention
eliminates the need to separately induce a pigment in the organism
before treatment begins. This saves time, cost, and eliminates the
chance of side effects resulting from inducing the pigment. [0256]
With respect to treatment by inducing a pigment and using a high
energy light to destroy an infection by excessive heat, the
invention eliminates the need for a large amount of energy to
destroy the organisms by excessive heat which may also cause damage
and discomfort to the patient. The invention uses significantly
less energy and thus has a much lower risk of complications. [0257]
With respect to other treatments used for existing infections, this
treatment can also be used periodically to prevent infections from
becoming established. This is particularly desirable for those who
are predisposed to skin and nail infections or persons that such
infections pose a significant threat.
[0258] Although the descriptions above contain many specificities,
these should not be construed as limiting the scope of the
invention but merely as providing illustrations of some of the
presently preferred embodiments of this invention. For example,
other sources of radiation may be used if they have the properties
necessary to inactivate organisms, penetrate sufficiently, and are
safe to humans or animals, etc.
[0259] Thus the scope of this invention should be determined by the
appended claims and their legal equivalents, rather than by the
examples given.
* * * * *