U.S. patent application number 13/436087 was filed with the patent office on 2013-02-28 for tattoo removal system and method.
The applicant listed for this patent is Michael P. O'Neil. Invention is credited to Michael P. O'Neil.
Application Number | 20130053757 13/436087 |
Document ID | / |
Family ID | 47744691 |
Filed Date | 2013-02-28 |
United States Patent
Application |
20130053757 |
Kind Code |
A1 |
O'Neil; Michael P. |
February 28, 2013 |
Tattoo Removal System and Method
Abstract
A treatment system and method includes use of a chemical
facilitator to provide a result-effective event against one or more
negative therapeutic effects related to exposing to a light output
a skin portion including a condition treatable in whole or in part
with light. In one exemplary embodiment for skin treatment
including tattoo removal, perfluorodecalin is used to inhibit or
resolve whitening, for example to speed a laser therapy
session.
Inventors: |
O'Neil; Michael P.; (Dublin,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
O'Neil; Michael P. |
Dublin |
CA |
US |
|
|
Family ID: |
47744691 |
Appl. No.: |
13/436087 |
Filed: |
March 30, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61528130 |
Aug 26, 2011 |
|
|
|
61595065 |
Feb 4, 2012 |
|
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Current U.S.
Class: |
604/20 |
Current CPC
Class: |
A61M 35/006 20130101;
A61K 31/025 20130101; A61B 2018/00577 20130101; A61K 41/00
20130101; A61P 17/10 20180101; A61B 18/203 20130101; A61K 2800/81
20130101; A61N 5/0616 20130101; A61B 2017/00769 20130101; A61B
2018/0047 20130101; A61K 8/0208 20130101; A61K 8/70 20130101; A61P
17/00 20180101; A61Q 19/00 20130101; A61Q 1/145 20130101; A61B
2018/00458 20130101; A61N 5/062 20130101 |
Class at
Publication: |
604/20 |
International
Class: |
A61M 37/00 20060101
A61M037/00; A61N 5/067 20060101 A61N005/067 |
Claims
1. A method for tattoo removal including: (a) applying
perfluorodecalin to a treatment area proximate a tattoo portion;
and (b) exposing the tattoo portion to a laser output.
2. The method of claim 1, wherein step (b) follows step (a).
3. The method of claim 1, wherein step (a) follows step (b).
4. The method of claim 1, wherein step (a) and step (b) occur
concurrently.
5. The method of claim 1, wherein step (b) results in a whitening
of the tattoo portion and step (a) includes substantially resolving
the whitening.
6. The method of claim 1, wherein step (a) includes substantially
inhibiting whitening due to laser light exposure.
7. The method of claim 1, wherein the tattoo is exposed to n laser
passes, wherein n is an integer greater than one and less than
five.
8. The method of claim 7, wherein one interval between two of the n
laser passes is substantially less than about twenty minutes.
9. A tattoo removal method comprising promoting optical
effectiveness using a chemical facilitator proximate a phototherapy
treatment area below a skin surface.
10. The method of claim 9, wherein the chemical facilitator
includes perfluorodecalin.
11. The method of claim 9, wherein the phototherapy treatment area
is a laser therapy treatment area.
12. The method of claim 9, wherein the treatment area includes a
tattoo portion.
13. The method of claim 9, wherein promoting optical effectiveness
includes reducing whitening.
14. The method of claim 9, wherein promoting optical effectiveness
includes preventing whitening.
15. The method of claim 11, wherein the laser therapy treatment
includes a first laser therapy pass and a second laser therapy
pass, and wherein promoting optical effectiveness includes having a
time interval between the first laser therapy pass and the second
laser therapy pass of less than about 20 minutes.
16-30. (canceled)
Description
RELATED APPLICATIONS
[0001] This application relates and claims priority to: the U.S.
provisional patent application Ser. No. 61/528,130 entitled "System
and Method for the Treatment of Vascular Lesions," filed on Aug.
26, 2011, by Michael P. O'Neil; and the U.S. provisional patent
application Ser. No. 61/595,065 entitled "System and Method for
Tattoo Removal," filed on Feb. 4, 2012, by Michael P. O'Neil.
FIELD OF THE INVENTION
[0002] The invention relates generally to systems and methods for
skin therapy procedures, and more particularly in one exemplary
embodiment, to systems and methods including chemical use in one or
more treatment processes or steps associated with skin tattoo
procedures (e.g., tattoo lightening, part or full tattoo removal),
which hereafter may be more generally referred to as "tattoo
procedures" or a "tattoo procedure."
[0003] In another aspect, the invention more particularly relates
to tattoo procedures including use of a chemical to promote
treatment.
[0004] In another aspect, a chemical delivery process or step may
occur (i) before, (ii) after, and/or (iii) concurrently with, use
of an emitter or light-generating device for a tattoo procedure
(e.g., a laser, a lamp (such as a flash lamp as used in an intense
pulsed light (IPL) device or application), or other light output
device).
[0005] In another aspect, the chemical may be a topical
chemical.
[0006] In another aspect, the chemical may include a
fluorocarbon.
[0007] In another aspect, the chemical may include a
non-hydrocarbon surfactant.
[0008] In another aspect, the chemical may include a
fluorosurfactant.
[0009] In another aspect, the chemical may include
perfluorodecalin.
[0010] In another aspect, the invention more particularly may
relate to a system or method comprising a sterile device including
a chemical.
[0011] In another aspect, the sterile device may be a single use
device, and the single use device may include a topical
chemical.
[0012] In another aspect, the sterile device may include one or
more of: a fluorocarbon; a non-hydrocarbon surfactant; a
fluorosurfactant; and perfluorodecalin.
[0013] The above-listed aspects are not necessarily limiting on the
invention, nor is one or more of the listed aspects necessarily
required in an invention embodiment. The aspects are set forth
above without limitation simply to describe the field of the
invention.
BACKGROUND OF THE INVENTION
[0014] There has been a long felt need for a treatment system and
method for tattoos, for tattoo procedures, etc. that is effective
without the undesirable side effects of the prior art. There is no
universally accepted tattoo treatment. Laser phototherapy
(photothermolysis) is perhaps the best treatment regimen available
to date for tattoo lightening and removal.
[0015] Physicians often use laser phototherapy involving lasers
operating at a variety of wavelengths and power and fluence levels.
Some physicians prefer Q-switched Nd:YAG lasers operating at 1064
nm. Others prefer typically Q-switched alexandrite lasers operating
at 755 nm. Still others prefer dye lasers operating in the visual
portion of the spectrum, or, for example, frequency doubled Nd:YAG
lasers operating at 532 nm, sometimes described as "KTP lasers",
KTP being the crystal which doubles the frequency of the laser.
Many other laser types and wavelengths have been used in tattoo
procedures as well.
[0016] While some favorable treatment results have been achieved,
no treatment regimen is without problems. For example, full
thickness burns that leave permanent scars have been observed as
adverse events following laser phototherapy. Thus, although various
devices and techniques have been used, none so far have proven
significantly effective.
[0017] One reason for problems or adverse events in tattoo
treatment may relate to the unpredictable nature of the thermal
conversion of oxyhemoglobin (HbO.sub.2) and deoxyhemoglobin (RHb)
into methemoglobin (metHb). metHb has a much higher optical
absorption relative to HbO.sub.2 or rHb in the near infrared (NIR)
portion of the spectrum thus facilitating thermal runaway once
conversion has started. This unpredictable, pseudo-instantaneous
conversion is of particular concern in connection with the use of
NIR light (i.e., the NIR portion of the spectrum (e.g., around 1064
nm)), which is otherwise desirable for use since NIR light
penetrates more deeply into the treatment site than visible light.
Use of NIR light thus may permit tattoo treatment to a greater
depth, which may result in a better outcome as more of the area or
volume including the tattoo portion to be treated can be treated at
one time. Prior systems and methods simply are not significantly
effective in controlling the thermal conversion of HbO.sub.2 and
RHb into metHb.
[0018] Another reason for adverse events in tattoo treatment using
prior systems and methods may be the unpredictable nature of the
treatment site. At all wavelengths, including the isosbestic point
between HbO.sub.2 and RHb (approximately 810 nm), the optical
absorption of the blood in the vessels can significantly change in
the course of a Q-switched or similar laser pulse. In practical
terms, a pulse that is perfectly well tolerated in one location or
tattoo portion may induce adverse effects (e.g., burning, scarring,
pain, hypopigmentation, hyperpigmentation) in another nearby
location or portion. This is because the local scattering,
absorption, and/or other properties proximate to the tattoo may
change from site to site, which contributes to the uncertainty of
the extent of photothermal conversion of HbO.sub.2 and RHb into
metHb from site to site. Blood treated in the vasculature at one
location proximate the tattoo may thermally convert into metHb to a
different extent than blood in the vasculature in a different
location proximate the tattoo.
[0019] A somewhat similar yet separate reason for adverse events in
tattoo procedures using prior systems and methods may relate to an
unacceptably low level of treatment repeatability. Unwanted
uncertainty and results stem from the unpredictability associated
with optical and physiological differences across patients. Every
patient, every tattoo, etc. is different. An effective set of
treatment parameters in one patient may unexpectedly cause an
adverse event in another patient with a seemingly identical tattoo
or condition. Prior systems and methods simply lack a desired
robustness in that they are not significantly effective in
controlling factors, e.g., the thermal conversion of HbO.sub.2 and
RHb into metHb, across individual patients in a treatment
group.
[0020] One problem, then, in a particular aspect may be viewed as
an optical "runaway" effect. Prior systems and methods may be
unattractive because this adverse event may occur, for example, as
the laser used in treatment is gradually increased in power and/or
fluence. As photo-thermal conversion of one or more hemoglobin
species into metHb occurs, suddenly a small change in one or more
laser operating parameters or one or more treatment conditions may
have a grossly larger effect due to the new presence of metHb. As
one example, variations in pressure that the physician applies to a
laser hand piece may induce varying degrees of exsanguination,
altering the optical properties of a treatment area, and
confounding predictability of photo-thermal conversion. Purpura can
result from this effect as well.
[0021] Differences in the types of tattoos treated also results in
problematic outcomes. Certain tattoo colors (e.g., yellow, green,
brown) typically are difficult to treat as compared to other colors
(e.g., black) using prior approaches. There is no significantly
effective prior system and method applicable to the wide variety of
tattoo colors (including difficult to treat colors).
[0022] Another problem associated with prior art tattoo procedures
is that often such procedures are messy. Typically, debris is
ejected from a treatment site, e.g., during laser use. The debris
may be solids, liquids, gases, aerosols, and/or other forms of
ejecta. Also, with some patients, a treating clinician may be
exposed as a result to an unacceptable risk of exposure, e.g., to
HIV, hepatitis-C, and/or other infectious diseases. There is no
significantly effective prior system and method to help control
such ejecta and reduce such adverse risks.
[0023] Another problem associated with prior art tattoo procedures
may stem from treatment side effects. By way of example, during a
laser treatment session, exposure of a treatment area to a laser
output may create one or more conditions within the treatment area
that tend to reduce the effectiveness of subsequent laser
exposures. One example of such side effects is a "whitening" of the
area treated.
[0024] During tattoo treatment, a "whitening" reaction typically
occurs, as evidenced by the formation of bubbles, e.g., in the
dermis. The whitening reaction typically occurs immediately upon
first laser exposure, with results of the reaction remaining during
and after subsequent laser exposures in the same session. The
whitening reaction may include, result in, or be caused by, the
generation of bubbles or other factors, e.g., due to rapid heating
or energy transfer associated with laser exposure, due to
laser-induced shock waves, due to microscopically "explosive" cell
or other reactions, due to two photon processes (e.g., associated
with use of a picosecond or faster laser), etc.
[0025] The "bubbles" associated with whitening may be
micro-cavitation bubbles and/or other events and/or circumstances
capable of having similar or other negative therapeutic effects,
e.g., attenuation of light, light scattering, etc. For convenience
only, and without limitation, such bubbles and/or other events
and/or circumstances shall be referred to herein individually and
collectively as a "bubble" or "bubbles."
[0026] Bubbles generally may be located in an area or volume
including a portion of the dermis, although other locations are
possible too. The bubbles generally may be located in an area or
volume including a portion of skin. Heating may be localized,
and/or may produce or otherwise cause or promote localized bubble
generation. Typically, tissue, skin, tattoo pigment, the dermis
portion, etc. are heated during treatment.
[0027] It has been observed that a whitening reaction may fade over
about twenty minutes or more following the last laser exposure.
Such fading may be evidenced by the dissolving of bubbles including
gas, or by other factors associated with bubble reduction.
Resolution of the whitening reaction may be caused at least in part
by the cooling of one or more heated portions.
[0028] Whitening is problematic at least in part because the
presence of bubbles in the treatment area from a first laser pass
may attenuate or weaken the delivery of light in one or more
subsequent laser passes. For instance, light impinging on bubbles
may scatter in multiple directions, including away from the
treatment area. Thus, bubble presence reduces light therapy
effectiveness.
[0029] Typically, clinicians in tattoo procedures may avoid in part
some of the adverse consequences of whitening simply by waiting for
the unwanted whitening condition to resolve naturally. Where such a
therapy session includes, for example, four laser passes, the total
session treatment time (i.e., length of session) may equal about
60-80 minutes or more.
[0030] Treatment time, then, often is quite problematic. Typically,
prior art tattoo treatment includes, among other things, a single
treatment session including multiple (e.g., up to four) laser
exposures to a treatment area, with an interval of twenty minutes
or more between laser exposures. See, e.g., Kossida et al, Optical
tattoo removal in a single laser session based on the method of
repeated exposures, J. Am. Acad. Dermatology 2012 February 66(2):
271-7. Such lengthy treatment time often poses significant problems
for patients and clinicians alike. Both clinicians and patients
generally would prefer shorter treatment times as compared to such
extended periods. This is especially true when multiple treatment
sessions are required over a period of months to achieve desired
results.
[0031] Thus, what is needed is an improved method and system for
tattoo treatment that helps predictably and effectively treat
tattoos while controlling, reducing, minimizing, and/or eliminating
one or more of: (i) the optical "runaway" effect, (ii) system
operating or treatment parameter uncertainties, and (iii) one or
more other disadvantages that may be associated with prior art
systems and methods for treating tattoos (e.g., whitening,
attenuation, lengthy treatment times, etc.).
SUMMARY
[0032] The present disclosure provides a skin therapy procedure
system and method.
[0033] In one exemplary embodiment, a tattoo procedure comprising
laser therapy including chemical use provides for shorter treatment
times. For example, and without limitation, a single tattoo
treatment session for tattoo lightening or removal may last only a
few minutes, and/or a time interval between successive laser passes
may be less than about twenty minutes.
[0034] Other benefits and advantages of the present disclosure will
be appreciated from the following detailed description.
DESCRIPTION OF THE DRAWINGS
[0035] FIG. 1 shows an example of a tattoo on skin.
[0036] FIG. 2 is an exemplary representation of a treatment area
comprising a skin portion including the tattoo of FIG. 1.
[0037] FIG. 3 is a cross-sectional view of the skin portion and
tattoo shown in FIG. 2, along the line 3-3 in FIG. 2, as viewed
from an angle perpendicular to the cross-sectional plane in the
direction indicated by the arrows at line 3-3 in FIG. 2.
[0038] FIG. 4 is a flow chart depicting an exemplary prior art
tattoo removal method including a "WAIT" step.
[0039] FIG. 5A is an illustration of a laser pass treating the
tattoo shown in FIG. 3
[0040] FIG. 5B is an illustration of the tattoo shown in FIG. 3
immediately following the laser pass illustrated in FIG. 5A.
[0041] FIG. 5C is an illustration of the tattoo portion shown in
FIG. 5B after about twenty minutes or more of waiting in accordance
with prior tattoo procedures.
[0042] FIG. 6 is a flowchart of an exemplary embodiment of a light
therapy session including use of a chemical facilitator.
[0043] FIG. 7 is a flowchart of another exemplary embodiment of a
light therapy session including use of a chemical facilitator.
[0044] FIG. 8 is an illustration of an exemplary embodiment
including use of perfluorodecalin against whitening of the type
shown by way of example in FIG. 5B.
[0045] FIG. 9A is an illustration of an exemplary embodiment
including use of perfluorodecalin for the exemplary tattoo shown in
FIG. 3.
[0046] FIG. 9B is an illustration of an exemplary tattoo treatment
including the exemplary embodiment shown in FIG. 9A.
[0047] FIG. 10A is an illustration of another exemplary embodiment
including use of perfluorodecalin for the exemplary tattoo shown in
FIG. 3.
[0048] FIG. 10B is an illustration of an exemplary tattoo treatment
including the exemplary embodiment shown in FIG. 10A.
[0049] FIG. 11 is an illustration of the exemplary tattoo shown in
FIG. 3 following an exemplary treatment including an embodiment of
the disclosure.
[0050] FIG. 12A is an illustration of the exemplary tattoo shown in
FIG. 3, following an exemplary treatment, including more than one
laser pass, and including whitening.
[0051] FIG. 12B is an illustration of the exemplary tattoo shown in
FIG. 3, following an exemplary treatment, including more than one
laser pass, and including use of an exemplary embodiment of the
disclosure.
[0052] FIG. 13A is an illustration of the exemplary tattoo shown in
FIG. 3, following an exemplary treatment, including more than one
laser pass, and including use of an exemplary embodiment of the
disclosure against whitening.
[0053] FIG. 13B is an illustration of the exemplary tattoo shown in
FIG. 3, following an exemplary treatment, including more than one
laser pass, and including use of an exemplary embodiment of the
disclosure.
DETAILED DESCRIPTION
[0054] Embodiments of the invention and various alternatives are
described below. Those skilled in the art will recognize, given the
teachings herein, that numerous alternatives and equivalents exist
which do not depart from the invention. It is therefore intended
that the invention not be limited by the description set forth
herein or below.
[0055] One or more specific embodiments of the system and method
will be described below. These described embodiments are only
exemplary of the present disclosure. Additionally, in an effort to
provide a concise description of these exemplary embodiments, all
features of an actual implementation may not be described in the
specification. It should be appreciated that in the development of
any such actual implementation, as in any engineering or design
project, numerous implementation-specific decisions must be made to
achieve the developers' specific goals, such as compliance with
system-related and business-related constraints, which may vary
from one implementation to another. Moreover, it should be
appreciated that such a development effort might be complex and
time consuming, but would nevertheless be a routine undertaking of
design, fabrication, and manufacture for those of ordinary skill
having the benefit of this disclosure.
[0056] Further, for clarity and convenience only, and without
limitation, the disclosure (including the drawings) sets forth
exemplary representations of only certain aspects of therapeutic
events and/or circumstances related to this disclosure. Those
skilled in the art will recognize, given the teachings herein,
additional such aspects, therapeutic events and/or circumstances
related to this disclosure, e.g., additional elements of the
dermis, the tissue, and the tattoo; events occurring within the
stratum corneum, epidermis, and upper and lower dermal regions;
etc. Such aspects related to this disclosure do not depart from the
invention, and it is therefore intended that the invention not be
limited by the certain aspects set forth of therapeutic events and
circumstances related to this disclosure.
[0057] FIG. 1 shows an example of a tattoo 10 (i.e., a broken
heart) on skin 20. A skin portion 30 including the tattoo 10 is
shown in FIG. 2. FIG. 3 is an exemplary cross section of the skin
portion 30 and tattoo 10, taken along the line 3-3 in FIG. 2.
[0058] FIG. 4 is a flowchart that illustrates an exemplary prior
art tattoo removal laser therapy session. The session includes a
method including a "WAIT" step 120. During the treatment session
illustrated in FIG. 4, for each laser pass, a waiting period of
about twenty minutes or more may be required, to allow time for
whitening to resolve naturally.
[0059] Referring to FIGS. 2 and 3, tattoos may be located in the
dermis 70, below a skin surface 40, the stratum corneum 50, and the
epidermis 60 (i.e., located below the D-E junction 80). The
location, shape, and overall make up of every tattoo is different.
FIG. 2 illustrates that, in general, tattoos may typically reside
below the D-E junction 80 in the upper portion of the dermis, and
may include a plurality of phagocytosed cells 90 including pigment.
The cells 90 naturally migrate slowly, if at all, over time, giving
the tattoo a certain degree of permanence.
[0060] Although a tattoo may appear to the naked eye to include
sharp lines or edges, for most tattoos a closer examination under
the skin surface typically reveals otherwise. The surfaces and
edges of a tattoo may be quite bumpy or rough, due in part to the
imprecision associated with tattoo formation. Thus, a tattoo cross
section may have a varying depth, as illustrated for example in
FIG. 3.
[0061] FIG. 3 shows an exemplary cross section of the tattoo of
FIG. 2, taken along the line 3-3, when viewed from an angle that is
generally perpendicular to the cross-section face and in the
direction indicated by the arrows at line 3-3 in FIG. 2. The tattoo
10 as shown in FIG. 3 includes a plurality of phagocytosed cells
90. The distribution of such cells 90 may vary. The volume
including the tattoo may include other features in addition to the
phagocytosed cells 90, e.g., an interstitial space between the
cells 90. For clarity and convenience only, FIGS. 2, 3, 9A and 10A
illustrate an outline of a tattoo portion and phagocytosed cells,
and the FIGS. 5A-C, 8, 9B, 10B, 11, 12A-B, and 13A-B illustrate the
outline only (although it is and should be understood that such
tattoo portions describe and include the phagocytosed cells and
other features, despite the absence of any express illustration of
the same).
[0062] The disclosure relates generally to systems and methods
including chemical use in one or more treatment processes or steps
associated with skin tattoo procedures (e.g., tattoo lightening,
part or full tattoo removal) (which hereafter may be more generally
referred to as "tattoo procedures" or a "tattoo procedure").
[0063] In another aspect, the disclosure more particularly relates
to tattoo procedures including use of a chemical to promote
treatment.
[0064] In another aspect, a chemical application process or step
may occur (i) before, (ii) after, and/or (iii) concurrently with,
use of an emitter or light-generating device for a tattoo procedure
(e.g., a laser, a lamp (such as a flash lamp as used in an intense
pulsed light (IPL) device or application), or other light output
device).
[0065] In another aspect, the chemical may be a topical
chemical.
[0066] In another aspect, the chemical may include a
fluorocarbon.
[0067] In another aspect, the chemical may include a
non-hydrocarbon surfactant.
[0068] In another aspect, the chemical may include a
fluorosurfactant.
[0069] In another aspect, the chemical may include
perfluorodecalin.
[0070] In another aspect, the disclosure more particularly may
relate to a system or method including a sterile device including a
chemical.
[0071] In another aspect, the sterile device may be a single use
device, and the single use device may include a topical
chemical.
[0072] In another aspect, the sterile device may include one or
more of: a fluorocarbon; a non-hydrocarbon surfactant; a
fluorosurfactant; and perfluorodecalin.
[0073] In another aspect, a chemical application process or step
may occur (i) before, (ii) after, and/or (iii) concurrently with,
use of an emitter or a light-generating device for a tattoo
procedure (e.g., a laser, a lamp (such as a flash lamp as used in
an intense pulsed light (IPL) device or application), or other
emitter), wherein the chemical is: (a) a topical chemical, or (b)
not a topical chemical.
[0074] In another aspect, the chemical may be a topical chemical
including one or more of: (i) a fluorocarbon, (ii) a surfactant,
(iii) a fluorosurfactant, and (iv) a non-hydrocarbon surfactant;
either alone or in combination.
[0075] In another aspect, the topical chemical may include
perfluorodecalin.
[0076] In another aspect, a tattoo procedure may include one or
more applications of light from an emitter or light-generating
device to a skin area including a tattoo. More particularly, in
tattoo procedures including two or more light applications, one or
more chemicals may be applied to a skin area including a tattoo (i)
before, (ii) after, and/or (iii) concurrent with, each light
application. In one aspect, an applied chemical may include
perfluorodecalin and/or one or more other fluorocarbon compounds.
In another aspect, application of a chemical may include a topical
treatment of such skin area. In another aspect (e.g., in another
exemplary embodiment), a chemical may be injected under a skin
surface using one or more needles or another delivery device.
[0077] In another aspect, a tattoo procedure may include exposing a
skin area including a tattoo portion to: (a) one or more
applications of light from an emitter or a light-generating device,
wherein the time period between light applications is (i) greater
than, (ii) less than, and/or (iii) about equal to, twenty (20)
minutes; and (b) a topical chemical. The topical chemical may be
perfluorodecalin. Where light applications occur in a single
session, one or more of the intervals between skin light exposures
may be substantially less than about twenty minutes.
[0078] In general, a light application may include one or more
exposures of a treatment area to one or more emitter light outputs,
e.g., one or more laser pulses, lamp pulses, or the like. A
treatment area may be exposed to one or more emitter outputs. For
example, under circumstances in which an emitter output covers only
a portion of an intended treatment area, multiple outputs may be
necessary to obtain full treatment. That is, if an emitter output
for instance appears relatively small and circular in shape at the
surface of the treatment area, clinicians or others may use two or
more overlapping outputs, which may be fully or partially
overlapping, to treat a larger and/or non-circular tattoo area.
Typically, a treatment area may receive or be exposed to sufficient
outputs in such manner (e.g., size, placement, strength, time of
exposure, etc.) as to achieve a desired therapeutic result. For
example, an area may be treated until a desired whitening effect
occurs, which may be identified for instance by an observed color
change or other result; by achieving a desired evenness of
coverage; by achieving a desired completeness of coverage; etc.
[0079] For convenience, a group of one or more light applications
occurring together in a single time period may be referred to
herein as a "treatment session" or a "laser session." Further, and
again for convenience, multiple treatment sessions may be
identified based upon the amount of time between two or more groups
of light applications.
[0080] In a case where at least one treatment session includes only
one light application (i.e., a group of one) or multiple light
applications (i.e., a group of two or more), multiple treatment
sessions may be identified by the passage of more than about twenty
(20) minutes between one light application group and one or more
preceding or subsequent light application groups.
[0081] By way of example only, and without limitation, a skin area
including a tattoo may be treated by one or more light applications
on a first day (i.e., day 1), and one or more light applications on
a second day (i.e., day 2) that is different from the first day. In
such example, the treatment on day 1 may be regarded as a first
treatment session, and the treatment on day 2 may be regarded as a
second treatment session. Day 1 and day 2 may be consecutive days,
or day 1 and day 2 may be one or more days, weeks, or months
apart.
[0082] By way of further example only, and again without
limitation, a skin area including a tattoo portion may be treated
by one or more light applications during a first period (i.e.,
period 1), and one or more light applications during a second
period (i.e., period 2) that is different from the first period. In
such further example, the treatment during period 1 may be regarded
as a first treatment session, and the treatment during period 2 may
be regarded as a second treatment session, provided that the time
between period 1 and period 2 is greater than about twenty (20)
minutes. For instance, and without limitation, a single day would
include multiple treatment sessions when period one occurs during
early morning, and period two occurs during afternoon or evening on
the same day. Period 1 and period 2 may be consecutive periods
spaced more than about 20 minutes apart. Period 1 and period 2 also
may be spaced days, weeks, or months apart.
[0083] In general, multiple treatment sessions may be identified by
the passage of an amount of time between groups of light
applications that is more than about twenty (20) minutes; and, in
accordance with an exemplary embodiment of the disclosure, the
approximate amount of time of at least one treatment session
including multiple light applications may be less than about twenty
minutes multiplied by the number of light applications in the
session.
[0084] During tattoo treatment, a "whitening" reaction occurs, as
evidenced for instance by the formation of bubbles, e.g., in the
dermis. The whitening reaction typically occurs immediately upon
first laser exposure, with results of the reaction remaining during
and after subsequent laser exposures in the same session. It has
been observed that the whitening reaction and/or its results fade
over about twenty minutes following the last laser exposure, as
evidenced for example by the dissolving of gas bubbles. Other
factors may cause bubble reduction. The whitening reaction may
include, result in, or be caused by, the generation of bubbles or
other factors, e.g., due to rapid heating or energy transfer
associated with laser exposure, laser-induced shock waves,
microscopically "explosive" cell or other reactions, two photon
processes (e.g., associated with use of a picosecond or faster
laser), etc. The bubbles may be micro-cavitation bubbles. The
bubbles generally may be located in an area or volume including a
portion of the dermis. The bubbles generally may be located in an
area or volume including a portion of skin.
[0085] A "whitening" or "whitening reaction" in one aspect refers
to any event or combination or sequence of events, alone or in
combination, causing a negative therapeutic effect resulting from
exposure of a treatment area to a light output (e.g., a laser
output). The events, alone or in combination, in sequence or not,
may include a chemical reaction (or not); a physical change (or
not); and/or one or more chemical reactions (or not) and physical
changes (or not), either alone or in combination. In one aspect,
then, this disclosure describes a skin treatment method, including:
(a) exposing to a light output a skin portion including a condition
treatable in whole or in part with light; and (b) providing an
amount of a chemical facilitator sufficient to provide a
result-effective event against a negative therapeutic effect, e.g.,
related to step (a), of performing the skin treatment method,
related to the skin treatment method, etc. The result-effective
event can be a single event, and/or a sequence or combination of
events, and may include a chemical reaction (or not); a physical
change (or not); and/or one or more chemical reactions (or not) and
physical changes (or not), either alone or in combination. For
tattoo removal, one example of a negative therapeutic effect is
bubble formation in the dermis. There are, of course, other
negative therapeutic effects that one of ordinary skill in the art,
having the benefit of this disclosure, will recognize for the one
or more types of light output of particular interest (for tattoo
removal, skin treatments, and/or for other applications). A
result-effective event against a negative therapeutic effect may
counter one or more negative therapeutic effects or events, alone
or in combination. The result-effective event may include one or
more occurrences that, alone or in combination, may counter such
negative therapeutic effect or event in one or more ways, either
alone or in combination, e.g., prevention, resolution, reduction,
inhibition, neutralization, avoidance, amelioration, blockage,
forestalling, interruption, obstruction, prohibition, stoppage,
acting, accelerating, breaking down, solving, advancing,
expediting, stimulating, removing, pacing, controlling, causing,
generating, speeding, warming, cooling, facilitating, urging,
checking, slowing, etc. There are, of course, additional such ways
beyond those listed which will be apparent to one of ordinary skill
in the art having the benefit of this disclosure.
[0086] In one embodiment, a chemical facilitator sufficient to
provide a result-effective event against a negative therapeutic
effect is provided, or a facilitating step is performed, as one one
or more distinct events at t.sub.1, t.sub.2, t.sub.3, . . . ,
t.sub.n, where each event t.sub.1, t.sub.2, t.sub.3, . . . ,
t.sub.n, etc. is defined using a therapeutic reference scale. A
therapeutic reference scale may be anything of interest to a
physician, clinician, or other caregiver related to the patient and
therapy involved. Exemplary therapeutic reference scales include,
without limitation: time, presence or absence of a condition,
occurrence of an event, etc. Note, too, that each of t.sub.1,
t.sub.2, t.sub.3, . . . , t.sub.n may be defined using the same or
different therapeutic reference scales; related or unrelated
therapeutic reference scales; etc.
[0087] During a tattoo procedure, heating may be localized, and/or
may produce or otherwise cause or promote localized bubble
generation. Typically, tissue, skin, tattoo pigment, the dermis
portion, etc. are heated during treatment. Resolution of the
whitening reaction may be caused at least in part by the cooling of
one or more heated portions. Thus, in one exemplary aspect, an
exemplary embodiment of the invention may include a cooling step or
process before, during, or after light exposure, chemical
application, etc., to provide cooling related to the treatment
(e.g., cooling of the skin, the dermis, the treatment area, a
chemical, an applicator for light, an applicator for a chemical, an
emitter output delivery system, a bandage, a patch, a skin contact
device, etc.).
[0088] Again, whitening resolution typically occurs over time
following laser exposure. It has been shown that whitening reaction
resolution over about twenty minutes or more following laser
exposure may prove advantageous, particularly where such 20-minute
period is immediately followed by one or more laser exposures (with
a similar 20-minute resolution period following each such laser
exposure). Such process including 20-minute intervals between laser
passes may be referred to by some as the "R20" method. The R20
method has significant drawbacks, however. For example, use of the
R20 technique (e.g., including four laser passes) may require up to
eighty minutes (or more) of treatment time per treatment session,
which is impractical. Thus, there has been a substantial and long
felt need for a treatment system and method for tattoos that is
effective in shorter sessions.
[0089] An exemplary laser pass of the R20 method is generally
illustrated in FIGS. 5A, 5B, and 5C. As shown in FIG. 5A, light 200
from an emitter 210 penetrates the skin portion 30 and impacts the
tattoo 10 within the dermis 70. As a result, bubbles 220 form. In
addition, tattoo pigment dye 230 is released proximate the tattoo,
e.g., from the destruction of phagocytosed or rephagocytosed cells
of tattoo 10.
[0090] FIG. 5B illustrates the skin portion 30 following completion
of the laser pass illustrated in FIG. 5A. As shown, there is an
increase in the amount of dye 230 proximate the tattoo 10, as well
as an increase in the number of bubbles 220.
[0091] If a subsequent laser pass would be performed upon the skin
portion 30 as shown in FIG. 5B, such subsequent pass would be
ineffective. As noted, for example, by Kossida et al., the
administration of two passes separated by 30 seconds to 20 minutes
has been tested and is not more effective than a single pass.
[0092] Accordingly, in the R20 method, to accomplish multiple laser
passes, a delay of about 20 minutes or more is required for a skin
portion to naturally resolve from an initial state as illustrated
in FIG. 5B to a therapeutically more light-receptive state as
illustrated in FIG. 5C (i.e., for example, a state including fewer
bubbles 220, more dispersed dye 230, etc.). Put another way, while
a skin portion 30 can go from FIG. 5A to FIG. 5B relatively
quickly, for that same skin portion to go from FIG. 5B to FIG. 5C
takes much longer, i.e., about 20 minutes or more.
[0093] The R20 process also is generally illustrated in the
flowchart of FIG. 4. As shown, a single laser therapy session lasts
from start 100 to end 140. In step 110, light therapy first is
performed on a treatment area. Then, at step 120, the physician
must wait for about 20 minutes or more for whitening reduction to
occur naturally. After the delay, the treatment area assumes a
therapeutically more light-receptive state, and the physician may
choose at step 130 to end treatment (i.e., a one-pass laser
session) or continue light therapy with another laser pass (i.e., a
multiple-pass laser session). As shown in FIG. 4, in a
multiple-pass laser session step 110, step 120, and step 130 are
repeated until the session ends at step 140.
[0094] As described in this disclosure, very rapid resolution of
one or more whitening reactions and/or one or more whitening
reaction results may be achieved in one or more treatment processes
or steps including the use of a chemical. See, e.g., FIG. 6 and
FIG. 7. Such treatment including chemical use eliminates, among
other things, the problematic "WAIT" step of prior methods for
tattoo lightening or removal (e.g., the R20 method). In that way,
without limitation, such chemical and its use may be regarded as a
treatment facilitator and facilitating step, respectively. Compare,
e.g., FIG. 6 and FIG. 7 with FIG. 4 (stop sign/wait step in FIG. 4
only).
[0095] As illustrated in FIG. 6, in one embodiment a light therapy
session starts at step 2000 and ends at step 2050. First, a
determination is made at step 2010 whether to use a chemical
facilitator prior to light therapy. If no chemical facilitator is
used, the method proceeds at step 2030 with a treatment area
receiving light therapy. However, where a chemical facilitator is
used, the method provides for step 2020, wherein a chemical
facilitator is provided to the treatment area before the
performance of light therapy step 2030. Following light therapy,
the determination is made at step 2040 whether to provide
additional light therapy treatment. If so, step 2010, step 2020,
and step 2030, as well as step 2040, are repeated one or more
times. The therapy session ends at step 2050 when it is determined
at step 2040 that no further light therapy is to be provided during
the session.
[0096] In accordance with the disclosure, variations on the
embodiment illustrated in FIG. 6 may be used depending upon the
circumstances involved in a particular application. For instance,
one alternate embodiment is illustrated in FIG. 7.
[0097] As shown in FIG. 7, a laser therapy session extends from its
start 3000 to its end 3090. An initial decision is made at step
3010 regarding use of a chemical facilitator (or not). The
facilitator might be used, for example, to achieve a desired
inhibition of whitening during a subsequent light therapy step. If
no chemical facilitator is desired, light therapy is performed on a
treatment area at step 3020. At that point, following light
exposure, the determination is made at step 3030 whether additional
light therapy is warranted for the treatment area. If so, a return
to step 3010 follows.
[0098] If at step 3010 the determination is made to use a chemical
facilitator, then a subsequent determination is made at step 3040
whether chemical facilitator use will occur concurrent with the
application of light to the treatment area. If no concurrent use is
planned, then chemical facilitator is provided to the treatment
area at step 3050, and the method of the embodiment proceeds to
step 3020. Where concurrent delivery of light and a chemical
facilitator is not desired, application and delivery of chemical
facilitator may occur at step 3050 prior to light exposure using an
appropriate embodiment of the described system for the particular
circumstances involved. One example of such an embodiment and its
use for pre-treatment with chemical facilitator (e.g., before a
laser use) is illustrated in FIGS. 10A and 10B.
[0099] At step 3040, however, if the determination is made to
concurrently use a chemical facilitator and light therapy, then the
method proceeds to step 3060 where the chemical facilitator is
provided to a treatment area along with light. One exemplary
embodiment of the disclosure that provides for concurrent delivery
of chemical facilitator and light is illustrated in FIGS. 9A and
9B. Note, too, that depending upon the specific circumstances
involved, such exemplary embodiment also is capable of providing a
pre-treatment with a chemical facilitator prior to light
exposure.
[0100] Following step 3020, and following step 3060, the exemplary
method proceeds to step 3030, where a determination is made whether
to provide additional light therapy to the treatment area. If no
additional light therapy is required, the method proceeds to step
3070. At step 3070, a determination is made whether application or
delivery of additional chemical facilitator to the treatment area
is needed. Such additional chemical facilitator might be required,
for example, to rapidly clear any remaining whitening effects
before the end of the session at step 3090. Of course, the
determination made will depend upon the circumstances involved in
the specific treatment. If additional chemical facilitator is
required, it is provided at facilitating step 3080 and the session
then ends at step 3090; otherwise, the method proceeds from step
3070 to the end at step 3090.
[0101] In one embodiment, a chemical facilitator includes a
fluorocarbon. In another embodiment, the chemical used includes a
derivative of decalin. In another embodiment, the chemical used is
an organic compound including fluorine in which 0-100% of hydrogen
is replaced, e.g., by deuterium. In another embodiment, the
chemical includes hydrofluorocarbons. In another embodiment, the
chemical includes 1H-perfluoropentadecane
(hentriacontafluoropentadecane). The chemical may include one or
more of: (i) a fluorocarbon, (ii) a surfactant, (iii) a
fluorosurfactant, and (iv) a non-hydrocarbon surfactant.
[0102] In one exemplary embodiment, very rapid resolution of
whitening reaction results includes the use of a chemical including
perfluorodecalin (C.sub.10F.sub.18). Perfluorodecalin is a
fluorocarbon, and a derivative of decalin, in which all of the
hydrogen atoms are replaced by fluorine atoms. Perfluorodecalin in
general is regarded as chemically and biologically inert, and
stable up to about 400.degree. C. As more specifically described by
Tsai, "[l]ike liquid perfluoro-n-alkanes (CnF2n+2, n=5-9) (Tsai,
2009), perfluorodecalin (C10F18) is a colorless, odorless,
non-toxic, non-flammable, thermally stable, non-ozone-depleting,
and heavy compound (high density and viscosity) with high
volatility, low surface tension, high gas solubility, and very low
solubility in water. Currently, it is primarily and increasingly
used as a blood substitute (Lowe, 2008). In addition, it can be
used as a contrast agent in a variety of diagnostic imaging
techniques (e.g., ultrasound image) (Hall et al., 2000), temporary
intraoperative vitreous substitutes in vitreoretinal surgery
(ophthalmology) (Heimann et al., 2008), cosmetic and ointment
additive for repairing burned skin and wound surface (Oxynoid et
al., 1994), liquid ventilation used in the drug delivery (Kraft,
2001), carrier of glassified microspheres that contain vaccines
(Coghlan, 2004), reaction medium in organic and organometallic
syntheses (Hibbert et al., 1997; Sandford, 2003), volatile
surfactant used for gas modification of lubricants and in optics
and liquid lasers (Stoilov, 1998), and tracer gas in the
environmental quality modeling in the ocean, and groundwater
(Watson et al., 1987; Deeds et al., 1999)."
[0103] FIG. 8 illustrates an exemplary embodiment including
perfluorodecalin delivery to a treatment area using a patch 400
including perfluordecalin 300. The patch 400 includes a first
portion 410 and a second portion 420 including perfluorodecalin
300. As shown in FIG. 8, the patch is positioned on a skin surface
40, and perfluorodecalin has transferred from the patch 400 to an
area and volume proximate the tattoo 10. As illustrated,
perfluorodecalin may be present at various times not only proximate
the tattoo 10, but also proximate the epidermis 60, the stratum
corneum 50, and the environment 430 proximate the skin surface.
[0104] As illustrated in FIG. 8, as the patch 400 is moved across
the skin portion 30 in an initial state following a laser pass
(e.g., a state as shown for example in FIG. 5B), a very rapid, and
perhaps almost instantaneous, reduction of whitening occurs, as
evidenced by a reduction of the bubbles 220 associated with the
transfer of perfluorodecalin from the patch 400 to an area
proximate the tattoo and whitening.
[0105] In one embodiment, a patch or other chemical facilitator
delivery means may be physically and/or physiologically similar to
skin. Such means may be adapted for intimate contact with a
patient; may be substantially optically transparent; and/or may be
soothing, benign, comfortable, and/or pleasant in use. Further, the
patch or other chemical facilitator delivery means may be
cooperative, e.g., with skin or other aspects of a particular
therapy, to help promote one or more result-effective events
against one or more negative therapeutic effects.
[0106] The perfluorodecalin need not be applied to the treatment
area using a patch, as illustrated for example in FIG. 8. Other
chemical and facilitator delivery means also may be used, depending
on the circumstances involved in a particular application. For
instance, application of perfluorodecalin to a treatment area from
a vial or other liquid container using a cotton swab has been shown
to effectively resolve whitening in laser therapy within seconds.
See the Pilot Study results included in this disclosure.
[0107] FIG. 9A illustrates an exemplary embodiment including
prevention of an undesired whitening effect by using a patch
including perfluorodecalin. As shown in FIG. 9B, a tattoo portion
10 is exposed to a light output 520 delivered through the patch
500. Prior to light exposure, the patch 500 is placed on a skin
surface 40 proximate tattoo 10. The patch 500 includes a surface or
region 510 that may be substantially impermeable to the
perfluorodecalin 300. The region 510 may be within the interior of
a patch, and/or the region 510 may form a portion or more of an
outer surface of the patch. Perfluorodecalin in the patch 500
between the surface 510 and the skin surface 40 transfers into the
skin portion 30 including tattoo 10. The patch may be optically
transparent. The patch including perfluorodecalin also may be
optically transparent.
[0108] In one embodiment, the patch 500 remains in place on the
skin surface until a sufficient amount of perfluorodecalin 300
enters the skin portion 30 proximate the tattoo 10 to achieve a
desired therapeutic result. A light output 520 from an emitter 530
is delivered through the patch 500 to treat the tattoo 10. See FIG.
9B. The emitter 530 may be moved as necessary across the patch to
treat a desired skin area. The emitter 530 may be in contact with
the surface 510, or may be spaced a distance from it. In an
alternate embodiment, the patch 500 may be removed prior to laser
therapy, so that light may directly impinge upon the skin portion
30 including perfluorodecalin 300 without passing through the patch
500.
[0109] As illustrated in FIG. 9B, perfluorodecalin proximate the
tattoo portion treated effectively inhibits whitening due to the
laser pass. The formation of bubbles 220 may be prevented in part,
and/or rapid or near instant clearing of a substantial portion of
formed bubbles may occur.
[0110] FIG. 10A and FIG. 10B illustrate another exemplary
embodiment of the disclosure, including perfluorodecalin delivery
to a treatment area using a swab including perfluorodecalin. The
tip 610 of the swab 600 may include cotton or other suitable
material to promote application or delivery of the perfluorodecalin
300. Perfluordecalin 300 may be provided to the swab tip 610 by
immersing or otherwise contacting the tip 610 at least in part in a
quantity of a perfluorodecalin-including substance (e.g., without
limitation, a gel; liquid perfluorodecalin in a vial or other
container or carrier; etc.). In one embodiment, the swab 600 itself
may include perfluordecalin 300, e.g., in the tip itself, or in a
chamber within the body of the swab 600. The chamber may be in, or
be capable of being placed in, direct fluid communication with swab
tip 610 or other delivery point. Of course, other configurations
may be used too, as will be apparent to one of ordinary skill in
the art having the benefit of this disclosure.
[0111] As shown in FIG. 10A, perfluorodecalin may be transferred to
an area or volume proximate the tattoo 10 by moving the tip 610
including perfluorodecalin one or more times across a portion of
the treatment area. Following such transfer, the swab or other
perfluorodecalin delivery means may be removed, and a light output
620 from emitter 630 may be used to treat tattoo 10. Similar to the
approach illustrated in FIG. 9A and FIG. 9B, delivery of the
perfluorodecalin 300 proximate the tattoo 10 helps prevent
undesired whitening following a laser pass. It is believed that
whitening prevention may result from one or more factors, alone or
in combination, including without limitation: the prevention of
bubble formation, the rapid resolution of bubbles formed, and one
or more other circumstances.
[0112] In one embodiment, perfluorodecalin is effective as a
facilitator against whitening in a laser tattoo lightening or
removal procedure. Regardless of the specific embodiment employed
for facilitator delivery, use of a chemical facilitator against
whitening may permit a physician to treat tattoos more rapidly than
prior methods, e.g., substantially less than about twenty minutes
or more between laser passes. Or, from another perspective, using
prior tattoo treatment systems and methods, typically it takes
about twenty minutes or more for a treatment site to transition
from initial states (such as those as illustrated for example in
FIG. 5A and FIG. 5B) to subsequent light-therapy-ready states (such
as those as illustrated for example in FIG. 5C). Chemical
facilitator use speeds such a transition.
[0113] Under the prior R20 and other treatment techniques,
whitening due to a single laser pass diminishes over about 20
minutes or more. Treatment areas transition slowly from an initial
state, and ultimately such areas naturally assume an improved state
that generally is more receptive to laser treatment as compared to
the initial state. Accordingly, the amount of total treatment time
associated with prior R20 and other treatment techniques is quite
significant.
[0114] In large measure, prior approaches are problematic due to
the considerable waiting times required in every treatment session.
Consider, for example, a physician having to wait twenty minutes
following each single laser pass to continue a multiple pass laser
treatment session. Such delay is inconvenient from a
time-management perspective for both the physician and the patient.
Further, the delay makes the management and flow of patients
through the physician's office quite difficult, especially where a
large number of patients may be treated each day, and also where
waiting room and clinical space for performing therapeutic
procedures is limited. Although the prior multiple pass method may
provide greater efficacy as compared to a single pass method, the
required lengthy treatment time may limit adoption of the prior
multiple pass technique.
[0115] The invention and this disclosure effectively address this
and other problems of prior methods. One exemplary embodiment
relates to use of a facilitating step to cause a treatment area to
assume more rapidly the same or a similarly receptive state for
laser treatment. In some cases, the receptive state may be an
improved or more receptive state from an optical and/or therapeutic
perspective. The facilitator used may include a chemical, and the
facilitating method portion may involve or include one or more
steps including chemical use. The facilitator may be a chemical
including perfluorodecalin. The chemical also may be a chemical not
including perfluorodecalin. For clarity and convenience only, and
without limitation, the Figures of this disclosure illustrate use
of perfluorodecalin as a chemical facilitator. The invention and
this disclosure, however, are not necessarily so limited. However,
chemical facilitator use, and the performance of a facilitating
step including chemical use, may enable treatment sites to
transition much more rapidly from initial states (examples such
initial states shown in FIGS. 8, 9A-B, and 10A-B) to later states
(an example of such later states shown, e.g., in FIG. 11).
[0116] Although the specific treatment mechanism of action may
involve multiple factors, it is believed that tattoo pigment
heating may perform a role, due to the tattoo pigment including one
or more metals and/or metal particles. Tattoo pigment heating may
result in a scattering or intercellular dispersion of tattoo
pigment to promote clearing. Cells including pigment (e.g.,
phagocytosed and/or rephagocytosed tattoo pigment particles) may be
heated or otherwise treated to induce cell breakdown, destruction,
or dispersion, that permits a clearing out of the tattoo pigment
dye via the lymphatic system. See, e.g., FIG. 11, which illustrates
dye 700 proximate tattoo 10 during laser treatment. Application of
laser light rapidly increases local enthalpy, and accompanying this
rapid heating and/or the other factors, almost instantaneous bubble
formation may occur. Bubble formation, which often may be
identified by a color change in the treatment area (e.g., a
whitening) is generally regarded as undesirable, at least in part
because bubble presence is thought to tend to inhibit optical
penetration at the treatment site, and may result in a required
interval of about twenty minutes or more between laser exposures
and/or laser passes to allow the bubbles to resolve.
[0117] Direct or indirect delivery of a chemical to a treatment
site via a carrier or other applicator assembly may promote
resolution of whitening and/or other undesired conditions
inhibiting treatment through one or more of: (i) reduction of local
surface tension; (ii) gas absorption; (iii) penetration into tissue
or skin; (iv) enhancement of gaseous diffusion (transcellular
and/or otherwise); (v) migration or flow through tissue; (vi)
refractive index matching; (vii) filling voids or gas-filled
interstices; (viii) reduction of optical scattering; and (ix)
optical clearing. These factors, and perhaps others, may relate to
the observed very rapid resolution with the use of a chemical
facilitator, such as one including perfluorodecalin.
Perfluorodecalin, for instance, generally has excellent
gas-carrying and gas-absorbtion properties, as demonstrated for
example by its use in liquid breathing applications. Using
perfluorodecalin, post-laser whitening resolution times of less
than about thirty seconds, and more particularly of less than about
five seconds, may be achieved. The actual time will depend of
course on the specific circumstances involved in a particular
application (e.g., size of the treatment area). Likewise, laser
sessions for tattoo removal may take only a few minutes of total
treatment time.
[0118] Resolution of conditions tending to inhibit treatment may be
identified in various ways. In addition to accepted techniques for
measurement of pertinent parameters (e.g., bubble size, density,
count, dissolution), a color change generally characterized by a
darkening of all or a portion of a whitened area may be observed.
In some cases, a treatment area may resolve and turn from white to
gray or black, or to the original color of the tattoo or portion
treated. Rates of changes in color change, one or more parameters,
etc., also may be identified.
[0119] In some laser treatments that include use of a R20
technique, the observed whitening (see, e.g., FIG. 5B as an
exemplary illustration of such whitening) mostly goes away in 20
minutes, but there can be one or more areas (e.g., relatively small
subsets of the treatment area) that resist and that do not resolve
very well in that timeframe. However, if one were to wait much
longer, i.e., for up to a month more (as in a typical treatment
method that involves multiple treatment sessions over a period of
months), such areas eventually would resolve substantially and most
or all whitening would go away.
[0120] In one exemplary embodiment of this disclosure, the delivery
of perfluorodecalin following one or more laser passes
substantially eliminates such areas that otherwise (i.e., without
perfluorodecalin use) would resist and not resolve very well in
about twenty minutes. Accordingly, a tattoo treatment or procedure
using perfluorodecalin as described herein may be more efficacious
than R20 and other treatment techniques by providing rapid
resolution of a substantially complete or entire treatment area
(e.g., up to nearly 100% resolution, complete resolution), e.g., in
a few minutes, in less than five minutes, almost instantaneously,
more rapidly than R20, in a few seconds, in less than five seconds,
etc., again depending upon the specific circumstances involved in a
particular application.
[0121] FIG. 12A illustrates a tattoo portion 12 during a multiple
laser pass therapy session. More specifically, FIG. 12A illustrates
the tattoo portion 12 in a state that may follow one of the later
laser passes in a multiple pass therapy. As shown, significant
amounts of dye 800, e.g., from phagocytosed cells including dye
pigment, surrounds the tattoo 12, which is shown as being smaller
in size than the tattoo 10 in the earlier Figures to reflect
multiple laser passes. Considerable whitening is present, as
evidenced by the large number of bubbles 810 at the treatment site.
The absence of perfluorodecalin or any other facilitator in FIG.
12A might suggest, for example, that the last laser pass performed
was completed without prior or concurrent use of a chemical
facilitator. Had such a facilitator been used, a state more closely
resembling the one shown in FIG. 12B would be expected (depending,
of course, on the specific circumstances involved). In FIG. 12B,
reduced whitening as compared to FIG. 12A is shown, as evidenced by
relatively fewer bubbles 910, and some remaining facilitator 900 is
present. As further shown, the amounts of dye 920 and the size of
the treated tattoo portions 12 are somewhat similar in FIG. 12A and
FIG. 12B, although that need not necessarily be the case. Indeed,
use of a chemical facilitator may result in more effective therapy
overall.
[0122] FIG. 13A illustrates one exemplary embodiment in which a
swab 1000 including perfluorodecalin 1010 is used in a tattoo
procedure including multiple laser passes and whitening.
Perfluorodecalin 1010 from the swab tip 1020 is provided in
sufficient quantity to a treatment area including bubbles 1030 and
tattoo pigment dye 1040, so that whitening is substantially
resolved. See FIG. 13B.
[0123] Perfluorodecalin use has an optical clearing effect. This
effect may itself improve the efficacy of the system and method of
the invention as compared to prior art techniques, e.g., those
including a typical approach of "wait a month or more" or "wait 3-6
weeks" between laser treatment sessions, R20 methods, etc. Indeed,
perfluorodecalin may facilitate laser treatment of any (or at least
a wide variety of) generally undesirable conditions in the dermis
(or elsewhere) for which laser treatment is used to promote the
elimination or removal of such conditions in whole or in part. In
one aspect, an exemplary embodiment of the invention includes
eliminating at least in part an undesirable skin condition for
which treatment with an emitter output promotes a therapeutic
benefit, including: (a) delivering perfluorodecalin to an area of
skin proximate the undesirable skin condition; and (b) exposing the
area of skin to a therapeutic amount of an emitter output. A
chemical facilitator other than one including perfluorodecalin may
be selected for use based on its desirable characteristics (e.g.,
excellent skin penetrating ability, desired therapeutic results,
and/or other factors). In some cases, the time between laser
sessions may be substantially shortened to less than about 3-6
weeks with chemical facilitator use.
[0124] In accordance with one aspect of the disclosure, tattoo
treatment may be achieved by pre-converting at least a portion of
the blood proximate the tattoo to metHb prior to laser treatment.
The "pre-conversion" to metHb prior to laser treatment may be
achieved with the topical application of benzocaine and/or similar
drugs. (For simplicity, only benzocaine shall be referred to
herein, but the invention is not necessarily so limited.) The
benzocaine penetrates the skin and chemically converts
oxyhemoglobin (HbO.sub.2) and deoxyhemoglobin (RHb) into
methemoglobin (met-Hb) with efficiency and speed.
[0125] The pre-conversion of one or more hemoglobin species into
metHb may bring the optical absorbance of the vessels in the
treatment area into an effectively unchanging conformance, thus
reducing or eliminating the possibility of sudden and unpredictable
changes during laser treatment, and making adverse events and/or
poor treatment outcomes less likely.
[0126] At some wavelengths, such as in the visible portion of the
spectrum, metHb has a lower absorption than some other hemoglobin
species. At other wavelengths, such as in the NIR (750 to roughly
1500 nm) metHb has a higher absorbance than most other hemoglobin
derivatives. The unknown relative concentration of these hemoglobin
species can grossly alter the response proximate the tattoo to a
given optical treatment condition.
[0127] Benzocaine may be delivered in many ways, e.g., as a spray,
a pre-treated wipe, a pre-filled applicator, a swab, a patch, or a
topical cream. In one embodiment, a benzocaine delivery means like
these or others supplies a controlled concentration of the drug to
the treatment site (e.g., the patient's skin), so as to avoid the
problems and potential adverse events associated with the
application of uncontrolled concentrations. For example, benzocaine
sprays and similar may induce methemoglobinemia under certain
circumstances, a treatable (methylene blue injection or
administration of oxygen) but cyanotic (asphyxiating) condition
that is potentially life threatening, especially in newborns who
have low circulating volumes of blood.
[0128] In accordance with one aspect of the present disclosure, a
transparent flexible dressing or patch, comprising a lipid rich
gel, may serve as a benzocaine delivery means. The gel includes a
desired concentration of benzocaine. The concentration of
benzocaine in the gel acts as a limit or check on the conversion to
metHb, in that the amount of benzocaine delivered from use of the
dressing or patch will not exceed the amount of benzocaine that is
preloaded into the gel.
[0129] In accordance with one aspect of the disclosure, the
benzocaine delivery means may comprise a flexible dressing or patch
including a gel that is transparent to the output of the treatment
laser. During treatment, a physician may leave the gel in place and
fire the laser through it. Alternately, a physician may remove the
gel prior to treatment laser use, and work on bare skin. Also, the
physician may reapply the gel from time to time, as
appropriate.
[0130] Similarly, perfluorodecalin may be delivered in many ways,
e.g., as a spray, as a pre-treated wipe, as a prefilled applicator,
in a patch, in a gel, with a swab, as topical cream. In one
embodiment, a benzocaine delivery means, like such examples listed
above or others, supplies a controlled concentration of
perfluorodecalin to the treatment site (e.g., the patient's skin),
so as to avoid any problems and potential adverse events associated
with the application of uncontrolled concentrations.
[0131] In one aspect, in one embodiment of the disclosure including
a lipid rich gel, the gel may include any non-polar, non-aqueous
material. For example, gels including fats, fatty acids, mono- and
poly-glycerides, glycol lipids, polyketides, glycerophospholipids,
and sphingolipids may be used. In addition, lipid rich gel may be
substances including non-polar, non-aqueous organics. Examples of
such substances include, by way of example and without limitation,
hexane, septane, nonane, naphtha, naphthalene, polyaromatic
molecules, perfluorohydrocarbons, perfluorodecalin, freons, octane,
n-hexane, and similar molecules.
[0132] In accordance with one aspect of the present disclosure, a
transparent flexible dressing or patch, comprising a lipid rich
gel, may serve as a perfluorodecalin delivery means. The gel
includes a desired concentration of perfluorodecalin. The
concentration of perfluorodecalin in the gel may act as a limit or
check on the presence and/or amount of gas at the treatment site,
and/or provide or promote enhanced optical clearing. A gel that is
fully organic, mixed aqueous/organic and/or fully aqueous may serve
as a carrier. Also, a gel may include an emulsion that includes one
or more chemicals or substances of interest (i.e.
perfluorodecalin).
[0133] In accordance with one aspect of the disclosure, the
perfluorodecalin delivery means may comprise a flexible dressing or
patch including a gel that is transparent to the output of the
treatment laser. During treatment, a physician may leave the gel
and/or dressing or patch in place and fire the laser through it.
Alternately, a physician may remove the gel and/or dressing or
patch prior to treatment laser use, and work on bare skin. Leaving
the flexible dressing or patch in place may help reduce or confine
the ejection or discharge of debris from the treatment site; defend
against ejecta; ameliorate and/or eliminate unwanted conditions,
etc., so as to help the clinician and/or patient, e.g., by acting
as a shield; by collecting discharge; by absorption; by selective
withdrawal or placement of substances; by cleaning, clearing,
and/or containing a treatment area; by deflection, reflection, or
the like; by beneficial scattering or redirection; by containment;
by encapsulation; by disinfection; by removal; by transformation;
and/or by delivering anesthetics, Gallenic topicals/drugs, or other
patient comfort enhancing materials; etc. The patch may be used
alone or in conjunction with a device to selectively perform, help
perform, promote, and/or assist in the efficacy of one or more of
the described desirable functions, processes, materials, etc.
[0134] In one exemplary embodiment, a carrier or applicator is
provided. The carrier or applicator is adapted to be positioned
proximate a skin treatment site. The carrier or applicator may
include a flexible, transparent portion. A chemical including
perfluorodecalin, another gas-absorbing chemical, or other chemical
facilitator may be disposed between the flexible, transparent
portion and the skin treatment site when the carrier or applicator
is positioned proximate to the skin treatment site. In one
embodiment, the flexible transparent portion may be disposed on a
first side of the carrier or applicator, the first side being
generally opposite from that portion of the carrier or applicator
that may be in full or partial contact with the skin.
[0135] The flexible, transparent portion of the carrier or
applicator may be substantially impermeable to perfluorodecalin (or
other gas-absorbing or chemical facilitators) in its liquid state,
in its gaseous state, or in both its liquid and gaseous states.
Such portion of the carrier or applicator may tend to prevent the
loss of perfluorodecalin or other chemical facilitators, e.g., due
to evaporation. Moreover, as the flexible, transparent portion of
the carrier and/or the perfluorodecalin and/or other chemical
facilitator warms (e.g., with body temperature), the vapor pressure
of the perfluorodecalin and/or other chemical facilitator will
increase. Under such circumstances, the flexible, transparent
portion of the carrier or applicator may further drive
perfluorodecalin and/or other chemical facilitator into the skin
treatment site, as both liquid and gas and all permutations of
liquid only, gas only, and liquid plus gas.
[0136] In one embodiment, a system for the delivery of
perfluorodecalin or other chemical facilitator to a skin treatment
site may include means to promote driving perfluorodecalin or other
chemical facilitator into the skin treatment site. Such means may
include or provide, either alone or in combination, one or more of
the following: vibration, ultrasound, heat, pressure, cooling,
chemical gradient, and chemical action potential.
[0137] In another embodiment, a system for the delivery of
perfluorodecalin or other chemical facilitator to a skin treatment
site may include a patch or other device that is transparent to a
laser output; that includes a top surface including a layer that is
impervious to fluids; that is flexible and conformable to a portion
of a patient's body; that includes a gel capable of hosting
perfluorodecalin; and that includes a means to promote the
temporary residence of perfluorodecalin in the gel. In one
embodiment, the system may be rigid in part. In one embodiment, the
system may include a release liner, foil pack, pouch, etc. to in
whole or in part house the patch or other device prior to use with
a patient, and to help promote the temporary residence of
perfluorodecalin in the gel.
[0138] In another embodiment, a system and method for tattoo
treatment includes delivery of perfluorodecalin or other chemical
facilitator to a skin treatment site following pretreatment or
preparation of the site. Pretreatment or preparation may include,
alone or in combination, use proximate the skin treatment site of
one or more of the following: a fractional laser; an ablative
fractional laser; a non-ablative fractional laser; one or more
micro-needle arrays; a heating apparatus, e.g., a heating pad or
surface; a cooling apparatus for cooling a skin portion; a
chemical, e.g., glycolic acid or dimethyl sulfoxide (DMSO).
Pretreatment or preparation may tend to increase the permeability
of a skin treatment site prior to the delivery of perfluordecalin
to the site. Other pretreatments or preparations also may be used
to create conditions to promote therapeutic benefit, e.g., cleaning
the treatment area. A chemical facilitator, e.g., perfluorodecalin,
also may be used in a pretreatment or preparation.
[0139] In another embodiment, a system and method for tattoo
treatment includes delivery of perfluorodecalin or similar other
chemical using a transport device for the chemical. The transport
device generally promotes penetration of the perfluorodecalin or
other chemical into the treatment area. Examples of transport
devices include, without limitation: one or more needles, one or
more syringes, a microneedle array, one or more injectors, glycolic
acid, DMSO, penetrating oils, freons, iontophoretic transdermal
systems, etc. that enhance transdermal transfer and/or
permeability.
[0140] The optical power densities used to treat tattoos can be
uncomfortable; pain may induce patient motion and distress, thus
reducing calm, even proper optical delivery of the therapeutic
laser beam by the operating physician. Thus, in accordance with one
aspect of the disclosure, the administration of a drug for
pre-conversion of one or more hemoglobin species into metHb, and/or
the delivery of a chemical facilitator (e.g., perfluorodecalin),
occurs along with the administration of an anaesthetic. In some
cases, the pre-conversion drug may also serve as an anaesthetic,
either alone or in conjunction with one or more other anaesthetic
agents. Benzocaine, for example, is an effective pre-conversion
drug that also is an effective topical anaesthetic (indeed, this is
its formal indication for use). An anaesthetic agent, which may or
may not promote pre-conversion, may be administered to patients in
addition to perfluorodecalin (e.g., before, during, of after
administration of perfluorodecalin).
[0141] Other dermatological conditions may benefit from treatment
in accordance with one or more aspects of the disclosure, for
example by changing (increasing or decreasing) the optical
absorption of the treatment site (rendering it more susceptible to
certain wavelengths of treatment light), reducing pain, or both.
Such conditions and treatment sites include, without limitation,
angiomas, hemangiomas, telangiectasias, varicosities, fine lines,
wrinkles, scars, skin surface imperfections, areas of skin
dispigmentation, freckles, age spots, solar lentigines, acne,
hyperpigmentation, hypopigmentation, benign pigmented lesions, and
other such or related conditions. Further, both the Title and the
Abstract of this application are provided for convenience only, and
should not necessarily limit the scope of the invention and
disclosure.
[0142] In accordance with another aspect of the disclosure, in some
embodiments it may be desirable to alter the preferential
(selective) absorbance of one side of the vasculature in the sense
of arterial vs. venous blood using the pre-conversion method
described herein.
[0143] In accordance with another aspect of the disclosure, in some
embodiments it may be desirable to treat background dyschromia (red
or brown) by changing the absorbance of blood using the
pre-conversion method described herein and also allowing use of
more deeply penetrating wavelengths.
[0144] In accordance with one aspect of the disclosure, topicals
and other agents that may promote the formation of metHb may be
used. Many other topically applied substances can increase the
local concentration of methemoglobin in the vasculature.
Antibiotics, such as trimethoprim, sulfonamides and dapsone; local
anesthetics, such as articaine, lidocaine and prilocalne; and other
substances such as aniline dyes, metoclopramide, chlorates,
bromates and nitrates, especially bismuth nitrate, can convert
oxyhemoglobin and deoxyhemoglobin into methemoglobin.
Exemplary Treatment Systems and Methods:
[0145] The following are only a few exemplary embodiments of
treatment systems and methods in accordance with the
disclosure:
For Port Wine Stains:
[0146] Apply a small (roughly 2 cm.sup.2) pad saturated with
benzocaine, or up to 20% or more benzocaine, formulated so as to be
lipophilic. Cover with an occlusive dressing for a few minutes.
Discard dressing and clean off residue with an acetone wipe. Apply
several coats of perfluorodecalin with a cotton-tipped applicator,
working the perfluorodecalin in somewhat. Cover the
benzocaine/perfluorodecalin-treated area with a transparent
dressing or patch (cut to size). Fire the treatment laser through
the transparent dressing or patch.
[0147] Laser selection: Q-switched alexandrite (755 nm) or
Q-switched Nd:YAG (1064 nm). The objective is to get greater
penetration depth in the NIR to treat the full thickness of the
lesion. At optimal fluence, one pass in the NIR may be sufficient.
Visible dye lasers also work, but because they are too strongly
absorbed, they may treat too superficially.
[0148] Fluence: Start with a relatively low fluence. Increase as
necessary to achieve a desired treatment. metHb has a higher
absorbance in the NIR than HbO.sub.2 or rHb. All three hemoglobin
species have greater penetration depth in the NIR than in the
visible.
For Tattoos:
[0149] The perfluorodecalin will have its best effect if it is
degassed and appropriately delivered in a lipophilic gel dressing.
In other words, it will assist in removing bubbles from areas of
the tattoo that have been treated with a laser pulse, allowing
greater penetration of subsequent treatment pulses without having
to wait as long for the bubbles to be absorbed as would be the case
with skin that has not been treated with perfluorodecalin.
Perfluorodecalin can absorb considerable amounts of various gasses.
Exposing degassed perfluorodecalin to atmospheric pressures for
long periods of time will render it less effective. A transparent
treatment patch composed of a suitable material such as a
lipophilic gel preloaded with degassed perfluorodecalin or similar
stored in a gas tight package until ready for application to the
skin would assist in the speed of removal of tattoos by absorbing
gas bubbles (or rendering them less troublesome) produced by the
treatment laser light, said bubbles rendering the tissue less
transparent to subsequent treatment laser light.
[0150] A chemical facilitator may be degassed in a variety of ways.
One way is to expose it to reduced pressure or vacuum, allowing any
dissolved gasses in the liquid to boil off and resulting in a lower
vapor pressure of those gasses than in the tissue to be treated. A
typical means would be to freeze the chemical facilitator into a
solid, expose the solid to hard vacuum, and then slowly allow the
solid to melt into a liquid so as to allow removal of dissolved
gasses without excessive evaporation. This is the
"freeze-pump-thaw" method.
[0151] Exposing the gel or system to partial pressures lower than
those typically encountered within the tissue immediately following
laser irradiation until the chemical facilitator alone, or in the
gel or in the system fell below that within the tissue would result
in a condition where gas would dissolve into the chemical
facilitator from the tissue until an equilibrium condition was
achieved. The lower the partial pressure of gas within the gel or
system, the more gas that can be transferred from the tissue.
[0152] In one exemplary embodiment, then, a method for resolving
whitening following laser therapy includes applying
perfluorodecalin to a treatment area prior to exposure of the
treatment area to a laser output, wherein the perfluorodecalin is
in a partially degassed state when applied to the portion of the
whitening.
For Neonates:
[0153] One of ordinary skill in the art, having the benefit of the
present disclosure, will recognize the particular benefits of the
disclosure for the treatment of neonates. Topical anesthetics in
accordance with the disclosure, e.g., benzocaine (or similar),
convert fetal hemoglobin to met fetal hemoglobin, so as to achieve
one or more of the advantages described herein.
Use of Ultra-Short Pulses:
[0154] In accordance with one aspect of an exemplary embodiment of
the disclosure, the system and method of the present disclosure
include use of lasers with pulse widths shorter than one
nanosecond, especially a few picoseconds or femtoseconds, which
promotes treatment as a result of more rapid delivery of energy to
the desired absorbers within a treatment site.
[0155] Super high energy, low power pulses may more effectively
disrupt tattoo ink microspheres than lower energy high power
pulses. In other words, picoseconds may be good, but femtoseconds
may be better. Depositing all that energy instantaneously before
the molecules can begin losing it as heat assures that the dye
spheres will certainly fall apart, allowing the dye within the
treatment site to diffuse into the tissue for intercellular clean
up. Since tattoo dyes are complex materials, the energy also may
tend to force them to decompose into smaller and/or more reactive
species, which may also promote the clean-up process.
Pilot Study
[0156] Results of a pilot study related to the disclosure will be
first released publicly in April 2012. The pilot study included
tattoo removal with repeated laser exposures in one session, in
which the need for 20-minute treatment intervals was eliminated.
The pilot study was conducted at the Laser & Skin Surgery
Center of New York (New York, N.Y.), under the direction of Roy G.
Geronemus MD.
[0157] As background for the pilot study, tattoo removal in a
single session with up to four repeated exposures each delivered
after resolution of whitening had been demonstrated to be more
effective than a single pass per session. A treatment delay of
twenty minutes for resolution of whitening limited practicality of
the technique, requiring up to eighty minutes of treatment time per
visit. Medical grade, sterile perfluorodecalin, an inert, non-toxic
liquid fluorocarbon with properties including optical clarity and
gas-carrying capacity, was evaluated in the pilot study in an
effort to speed resolution of cavitation-induced whitening
immediately after laser treatment of tattoos. Perfluorodecalin may
increase the optical penetration of lasers.
[0158] The pilot study was performed in consenting patients with
unwanted tattoos. Each tattoo was treated in whole or part with
topical perfluorodecalin by cotton swab prior to each laser pass.
Lasers and settings were selected by a dermatologist. During and
after treatments, extent and duration of whitening reaction was
assessed as well as appearance of adverse effects, including
pigmentary change or scarring. Each patient was seen at 3-6 weeks
for follow-up and possible continued treatment.
[0159] In fifteen tattoos, perfluorodecalin was applied prior to
each laser pass and the tattoo was treated with three Q-switched
ruby laser passes immediately following one another in a single
session. In five tattoos, a portion was treated with
perfluorodecalin prior to a single pass of Q-switched ruby or
Nd:YAG laser. All tattoos showed immediate whitening after laser
treatment. After each laser pass, the whitening reaction resolved
within five seconds of perfluorodecalin application. All treatments
were well-tolerated with local anesthesia. Subjects reported normal
to improved healing (amount of blistering, crusting or other
changes) compared with previous treatments and no adverse effects
occurred.
[0160] It was concluded that topical perfluorodecalin resolves
post-laser whitening within seconds and permits safe immediate
sequential treatment of tattoos in multiple passes (e.g., up to
four passes) in a single session, allowing more effective tattoo
removal in only a few minutes of treatment time (e.g., about 5
minutes, as compared to about 80 minutes with R20).
DEFINITIONS
[0161] The terms used herein and listed below have the meanings
indicated below.
[0162] The term "HbO.sub.2" means "oxyhemoglobin."
[0163] The term "RHb" means "deoxyhemoglobin."
[0164] The term "metHb" means "methemoglobin."
[0165] The term "NIR" means "near infrared."
[0166] The term "DMSO" means "dimethyl sulfoxide."
Other Exemplary Embodiments
[0167] Certain exemplary embodiments of the disclosure may be
described as set forth in the claims below. Of course, the listing
below (as well as each claim) may be modified in form and content,
and the listing is not exhaustive, i.e., additional aspects of the
disclosure, as well as additional embodiments, will be understood
and may be set forth and claimed in view of the description herein.
Further, while the invention may be susceptible to various
modifications and alternative forms, specific embodiments have been
shown by way of example in the drawings and will be described in
detail herein. However, it should be understood that the invention
is not intended to be limited to the particular forms disclosed.
Rather, the invention is to cover all modifications, equivalents
and alternatives falling within the spirit and scope of the
invention as defined by the following appended claims.
* * * * *