U.S. patent application number 13/144222 was filed with the patent office on 2011-12-01 for irradiation device.
This patent application is currently assigned to PHOTOCURE ASA. Invention is credited to Bjorn Klem.
Application Number | 20110295186 13/144222 |
Document ID | / |
Family ID | 40379469 |
Filed Date | 2011-12-01 |
United States Patent
Application |
20110295186 |
Kind Code |
A1 |
Klem; Bjorn |
December 1, 2011 |
IRRADIATION DEVICE
Abstract
An irradiation device for insertion into an orifice of the body
for providing photodynamic therapy or diagnosis comprises: a
housing 1, 21, 31, 51, 61, 71 adapted to be fully inserted and
secured in the orifice, the housing 1, 21, 31, 51, 61, 71 enclosing
an LED lamp system 5, 25, 35, 45, 54, 62, 72 and a power source 41,
68, 78, for powering the LED lamp system 5, 25, 35, 45, 54, 62, 72,
wherein the device is independently operational while located
within the orifice.
Inventors: |
Klem; Bjorn; (Oslo,
NO) |
Assignee: |
PHOTOCURE ASA
Oslo
NO
|
Family ID: |
40379469 |
Appl. No.: |
13/144222 |
Filed: |
December 16, 2009 |
PCT Filed: |
December 16, 2009 |
PCT NO: |
PCT/EP09/09037 |
371 Date: |
August 12, 2011 |
Current U.S.
Class: |
604/20 ;
607/92 |
Current CPC
Class: |
A61N 2005/0626 20130101;
A61N 2005/0645 20130101; A61B 5/0084 20130101; A61N 5/062 20130101;
A61K 31/221 20130101; A61N 2005/0611 20130101; A61P 17/06 20180101;
A61P 35/00 20180101; A61P 43/00 20180101; A61N 2005/0608 20130101;
A61K 9/0036 20130101; A61N 5/0603 20130101; A61K 41/0061 20130101;
A61P 17/10 20180101; A61N 2005/0658 20130101; A61N 2005/0652
20130101 |
Class at
Publication: |
604/20 ;
607/92 |
International
Class: |
A61N 5/06 20060101
A61N005/06; A61M 31/00 20060101 A61M031/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 22, 2009 |
GB |
0916666.1 |
Claims
1. An irradiation device for insertion into an orifice of the body
for providing photodynamic therapy or diagnosis, the device
comprising: a housing adapted to be fully inserted and secured in
the orifice, the housing enclosing a light emitting diode ("LED")
lamp system and a power source for powering the LED lamp system;
wherein the device is independently operational while located in
the orifice.
2. A device as claimed in claim 1 wherein the housing includes a
flexible outer portion which is, in use, adapted to adjust its
shape to form a secure fit with walls of the orifice.
3. A device as claimed in claim 2 wherein the flexible outer
portion forms a continuous surface which tapers outwards towards a
rear part of the device.
4. A device as claimed in claim 2 wherein the flexible outer
portion is formed of a resilient material.
5. A device as claimed in claim 1 wherein the entire housing is
flexible.
6. A device as claimed in claim 1 wherein the housing includes a
treatment surface, the LED system being arranged to emit radiation
from the treatment surface.
7. A device as claimed in claim 6 wherein the treatment surface is
fully transparent to light having wavelengths emitted by the LED
lamp system.
8. A device as claimed in claim 6 wherein the treatment surface has
at least one of (a) a size and (b) a shape adapted for
complimentary fit with a treatment area of the orifice such that,
when the device is in use, the treatment area is illuminated with
light from the LED lamp system.
9. A device as claimed in claim 6 wherein the treatment surface is
formed by a surface of a portion of a housing material, and the
material is arranged to diffuse light emitted from the LED lamp
system.
10. A device as claimed in claim 1, further comprising a switch for
activation of the LED lamp system.
11. A device as claimed in claim 10, wherein the switch is enclosed
within the housing and is arranged to be operated whilst sealed
within the housing.
12. A device as claimed in claim 1 wherein the LED lamp system is
arranged to provide, in use, a light intensity in the range of 1-50
mW/cm.sup.2.
13. A device as claimed in claim 1 wherein the LED lamp system
emits light having wavelengths in the range of 300-800 nm.
14. A device as claimed in claim 1, wherein the LED lamp system
includes a control circuit for regulating irradiation provided by
the LED lamp system.
15. A device as claimed in claim 14, wherein the control circuit
includes at least one of (a) a receiver for connection to a remote
terminal, (b) a feedback system, and (c) one or more performance
indicator lights for informing a user whether the device has
operated correctly.
16. A device as claimed in claim 1 further comprising a lens system
arranged to provide homogenous illumination over a treatment
area.
17. A device as claimed in claim 16 wherein the housing includes a
treatment surface, the LED lamp system being arranged to emit
radiation from the treatment surface, and the treatment surface
includes the lens system.
18. A device as claimed in claim 1, further comprising a drug
carrying area.
19. A device as claimed in claim 1, wherein the device includes at
least one feature that promotes single-use and/or prevents repeat
use.
20. A device as claimed in claim 14, wherein the control circuit is
programmed to provide pulsed illumination.
21. A device as claimed in claim 18, wherein the drug carrying area
carries a composition comprising a photosensitizer or precursor of
a photosensitizer.
22. A device as claimed in claim 21, wherein the composition
comprises 5-ALA or a derivative of 5-ALA.
23. A device as claimed in claim 22, wherein the composition
comprises a 5-ALA ester.
24. A device as claimed in claim 19, wherein at least one of (a)
the power source is arranged to provide power that is only
sufficient for a single-use, (b) a control circuit is arranged to
prevent re-use by means of features of its programming, and (c) the
control circuit includes a deactivation mechanism that destroys
circuitry or software when triggered.
Description
[0001] This invention relates to an irradiation device for
insertion into an orifice of the body for providing photodynamic
therapy or diagnosis of diseases, lesions and conditions
thereof.
[0002] An example of an orifice of the body where photodynamic
treatment is of benefit is the female reproductive tract.
Conditions affecting the female reproductive tract are discussed
below. Similar conditions, or conditions that respond to similar
treatments, can arise in other orifices, such as the rectum, ear or
nose.
[0003] The human papillomavirus (HPV) is a virus that can infect
the skin and mucus membranes in humans. More than 100 different
types of HPV have been identified. Several HPV types are
transmitted through sexual activity and are pathogenic. HPV is
estimated to be the most common sexually transmitted infection in
the US. Several hundred million women worldwide are infected with
HPV once in their life-time (.about.70%), with the highest
prevalence, 20-30%, occurring in young women. These viruses can
cause infections in the female genitalia and result in female
genitalia diseases like genital warts, dysplasia and cervical
cancer.
[0004] Cervical cancer is a life-threatening disease and is today
the third most common cancer form among women world wide.
Scientists agree that there is a strong correlation between the
development of cervical cancer and HPV. Persistent HPV infection of
the cervix may induce cell abnormalities including cervical
intraepithelial neoplasia (CIN), precancerous lesions, and
ultimately cervical cancer.
[0005] Fortunately mild cellular abnormalities including CIN1 have
a high degree of spontaneous regression (>60%), and this is a
condition that is normally only followed up by colposcopy. Moderate
to severe CIN (CIN2 and CIN3) have a lower degree of spontaneous
regression and a higher risk of progression. Patients with CIN2 and
CIN3 are therefore conisized, usually by surgical procedures
including diathermia, laser conisation and hysterectomy. The
efficacy is about 90%, but side effects are disturbing, causing
increased risk of bleeding, infection, stenosis, infertility and
preterm labour.
[0006] If not treated, the precancerous cells will progress into
more severe forms like carcinoma and neuroendocrine carcinoma.
Treatment methods for cervical cancer are, as with most other
cancer forms, dependent on the development stage of the disease.
Treatment of early stage cervical cancer is normally various forms
of surgery, while late stage cervical cancer is treated with
surgery in combination with radiation therapy and chemotherapy. The
most common chemotherapy of cervical cancer includes use of
cisplatin. It is estimated that around 11,000 women a year will be
diagnosed with cervical cancer, and that almost 4,000 will die from
the disease. The degree of survival (over 5 years) depends on the
stage of the disease and is, on average, above 50%.
[0007] Photodynamic therapy (PDT) is a therapeutic modality using a
combination of light and a photosensitizer. When illuminated at a
suitable wavelength the photosensitizer or "PDT drug" reacts with
tissue oxygen to form oxygen radicals that interact with cellular
organelles including the mitochondria and cell membranes. These
interactions cause cell necrosis or apoptosis (programmed cell
death). PDT is today used clinically for the treatment of several
diseases, including various skin diseases.
[0008] Typical products for use in skin PDT are Metvix.RTM.
(Galderma, Switzerland) and Levulan.RTM. (Dusa Pharmaceuticals Inc,
Wilmington, USA).
[0009] A range of photosensitizers are known from the scientific
literature. One type of such compounds is per se toxic to target
cells or species or have light emitting properties when exposed to
light. Such compounds have a relatively large molecular weight and
are often complex molecules like phthalocyanines, chlorines,
porphyrins and psoralens. Another, more clinically useful, type of
compound are photosensitizer precursors that per se are not
phototoxic or light emitting, but form photo-active compounds, e.g.
endogenous porphyrins, in vivo. Such compounds are typically
5-aminolevulinic acid (5-ALA) and derivatives of 5-ALA like 5-ALA
esters, and will be referred to hereafter as "precursors".
[0010] There is currently no product on the market for PDT or
diagnosis of diseases, lesions or conditions of the cervix.
However, there are several scientific reports on clinical research
related to PDT of the cervix including PDT of human papillomavirus
infections. In a recently published study (P. Soergel et al, Lasers
in Surgery and Medicine 40:611-615 (2008)), 24 patients with a CIN2
or CIN3 or a persistent CIN1 received local application of 5-ALA
hexylester in a thermogel formulation. The patients were advised to
stay supine for the next 3-5 hours before illumination which was
performed for 17 minutes with a laser at a high light dose of 100
J/cm.sup.2. At 2-3 months later, the clinical effect was assessed,
and a second PDT treatment was offered for individuals with an
incomplete response to the first PDT. All patients were scored at 6
months after the first treatment, and a complete response rate of
63% was found.
[0011] It is evident from the above that this is a time-consuming
treatment both for the patients and for the gynaecologists. The
patients will have to visit the gynaecologist to have the
formulation applied, they then have to stay supine for 3-5 hours
and then to visit the gynaecologist again for illumination. In
addition, many of the patients who did not respond to the first
treatment and had to go through the procedure once more.
[0012] The overall conclusion from these studies is that there is
room for improvement in the clinical treatment efficacy of PDT in
treating HPV and cervical cellular abnormalities. Furthermore, the
procedure is time-consuming both for the patients as well as for
the hospital personnel. Similarly, there is room for improvement in
the treatment of other conditions affecting the female reproductive
tract and in the treatment of conditions affecting other
orifices.
[0013] There are several patent documents describing various
devices for vaginal use, cervical drug delivery or photo-related
diagnosis or therapy.
[0014] US 2008/0065003 discloses a LED-based cervical PDT device
comprising an illumination head to be inserted into the cervical
region. An LED array is either placed within the illumination head
or in a hand piece connected to the head via a light guide. The
device is connected to an external power supply and the light
emitted by the LEDs is directed onto the cervix by a spherical
reflector within the illumination head.
[0015] GB 2370992 discloses an LED PDT device for treatment of the
cervix. This consists of a head portion containing an LED array
which is shaped for insertion through the vagina to fit closely
over the opening of the cervix. The head portion is connected to a
hand piece via a hollow stem, through which air and power are
supplied from an external air and power supply to the LED array.
The device is clamped into position for the duration of the
treatment.
[0016] As will be appreciated, both of these devices require
operation by a medical practitioner and so will normally be used
within a medical institution, such as a hospital or GP surgery. The
patient must remain still during the length of the illumination,
which is inconvenient and limits the practical length of each
treatment session.
[0017] In addition, the photosensitizer must be applied to the
cervical area prior to use of the device. It is usual with current
methods for the patient to wait several hours between application
of the photosensitizer/precursor and illumination.
[0018] PDT is today not a clinically valuable method for therapy of
CIN and other diseases/conditions of the cervix. This is due to the
ineffective results of therapy, as outlined in the above cited
report. Thus, there is a need for improved methods for therapy of
the cervix organ system.
[0019] Surprisingly, it has been found by the inventors of the
present invention that the use of a specific device, in combination
with a photosensitizer or precursor, improves therapy of cervical
cancer and other cervical diseases, lesions and conditions,
especially those diseases, lesions and conditions caused by HPV
infection. Similar improvements can be made in connection with
photodynamic treatment of other conditions affecting the female
reproductive tract like for instance vulvar intraepithelial
neoplasia (VIN) or vulvar carcinomas. Further, similar improvements
can be made in connection with PDT of cancerous or precancerous
conditions or lesions of any other orifice of the human or animal
body.
[0020] According to one aspect the present invention provides an
irradiation device for insertion into an orifice of the body for
providing photodynamic therapy or diagnosis, the device comprising:
a housing adapted to be fully inserted and secured in the orifice,
the housing enclosing an LED lamp system and a power source for
powering the LED lamp system, wherein the device is independently
operational while located in the orifice.
[0021] Unlike prior art devices, the device of the present
invention does not require the patient to remain at a medical
facility during treatment. Rather, use of the device will often
imply only one visit to the medical facility, after which the
patient is free to leave. Prolonged ongoing treatment can occur
while the patient continues with his or her normal daily
activities.
[0022] This is because the device is adapted to be fully inserted
and secured in the orifice and does not require connection to an
external power supply or light source during operation. By
"independently operable" it is meant that the device can provide
illumination for PDT without concurrent connection to any external
device. The device is hence fully self-contained and forms an
enclosed unit including both the light source and the power supply
required for photodynamic procedures.
[0023] As well as increasing the comfort and minimising disruption
to the patient, another advantage of the present invention is that
illumination can occur is preferably carried out at very low
fluence rates. Fluence rate, F, refers to the radiant power
incident on a unit area and is measured in units of W/cm.sup.2.
Illumination with low fluence rates (e.g. 10 mW/cm.sup.2) requires
that the illumination will have to occur over a relatively long
time period, e.g. many hours, in order to achieve the desired light
dose necessary to achieve a therapeutic effect, and hence is
impossible in a clinical (hospital) situation. However,
illumination using low fluence rates is known to strongly reduce
the patient discomfort (pain) during illumination, and may also
improve the PDT effect by allowing a continuous build-up of
endogenous porphyrins (from precursors) and to prevent oxygen
depletion during illumination (S. Jacques et al., "PDT with
ALA/PPIX is enhanced by prolonged light exposure putatively by
targeting mitochondria", SPIE Proceedings Vol. 2972, "Optical
Methods for Tumor Treatment and Detection", ed. T. Dougherty, San
Jose, February 1997, and M. Seshadri et al., Clin Cancer Res 14(9),
2796-2805 (2008)).
[0024] The device is therefore not only more "patient friendly", it
can also increase the efficacy of the treatment.
[0025] The shape of the housing can vary, but is generally designed
so that it comfortably fits within the orifice and remains in place
independent of the patient's physical activity. Where the orifice
of interest is the female reproductive tract, suitable shapes for
the outer portion of the housing can for example be similar to the
shapes of some contraceptive devices used to prevent pregnancy,
such as FemCap.RTM. and other similar devices intended for blocking
sperm from entering the uterus. For other orifices, other suitable
shapes and structures can be utilised, for example based on shapes
known for use as suppositories and/or pharmaceutical pessaries.
[0026] Although the present invention has been created with the
treatment of human patients in mind, it is also possible for the
device to be used in the treatment of other animals. Therefore the
shape of the housing will be dependent on the orifice where
treatment is required and on the anatomical structure of the animal
on which the device is intended for use.
[0027] The device can comprise a slim housing, which the walls of
the orifice will envelope and hold in place. When the device is for
vaginal use the housing may, for example, be similar in size and
shape to a tampon. The outer surface of the housing may be textured
to improve the grip of the device. A textured surface can also be
of benefit in providing a surface for the delivery of drugs to the
area of the body that requires treatment.
[0028] To ensure a comfortable and effective treatment for each
patient, devices of different sizes and/or shapes may be made
available. For example, in the case of treatment of the cervix
devices of three size may be provided for (i) patients that have
not been pregnant, (ii) patients that have had a pregnancy but not
carried to term and (iii) patients who have given birth.
[0029] For some orifices, for example the rectum, a simple
`torpedo` shape will enable the device to be inserted and secured.
However, for other applications additional features may be present
in order to ensure that the device is securely held within the
orifice during use. Hence, for vaginal use the housing preferably
comprises a flexible outer portion that can adjust its shape to
form a secure fit with the vaginal walls and enables the device to
be used within many different shapes and sizes of vagina. The
flexible outer portion also helps to decrease the risk of slipping
or misalignment of the device over an extended treatment period,
during which the patient may be physically active. A similar outer
portion may be used for a device intended for insertion in other
orifices, if required.
[0030] For insertion into the ear or nose the device may be shaped
based on known designs for ear or nose plugs.
[0031] The flexible outer portion can be formed from any material
capable of adjusting its shape. For example, the flexible portion
may be formed of an expandable, compressible or deformable
material. A housing at least partially comprised of deformable
material could adjust its shape during insertion to conform to the
diameter of the orifice. Alternatively an expandable material could
be used such that, after insertion, the outer portion of the
housing expands to firmly grip the walls of the orifice. The
expansion could be initiated through body heat, exposure to fluid,
removal from a delivery device/instrument etc.
[0032] Preferably however the flexible outer portion is formed of a
resilient material. This enables the shape of the flexible portion
to be altered while also providing a biasing outwards force to hold
the device in place. In order to achieve this effect the outer
diameter of the outer portion should be sized such that this must
be reduced in order to insert the device into the orifice. The
outer portion will then provide an outwards force to the walls of
the orifice.
[0033] The resilient material can be any resilient material
commonly used in medical devices; for example rubber, latex,
silicone or other natural, semi-synthetic or synthetic polymers or
copolymers.
[0034] The flexible outer portion can be any shape which is capable
of creating a secure fit with the walls of the orifice. For
example, the flexible outer portion may be provided in the form of
a number of discrete legs, ridges or other protrusions radially
and/or longitudinally spaced about and extending outward from the
housing. In other embodiments the flexible outer portion may form a
continuous outer surface of the housing. This surface could either
form the whole or a part of the exterior of the housing. For
example the outer portion may be a disk or cup-shaped section found
at either the front or rear of the device, or a covering which
extends over the entire length of the housing.
[0035] In a preferred embodiment the flexible outer portion forms a
continuous surface which tapers outwards towards the rear end of
the device i.e. the end of the device which, in use, is closest to
the entrance of the orifice. For example the outer portion can be
approximately frustoconical in shape.
[0036] Although it is only necessary for an outer portion of the
housing to be flexible, in certain preferred embodiments the entire
housing is flexible. Creating a device having a flexible housing
increases the comfort of the device and eases construction as only
a single material is required.
[0037] Preferably the housing comprises a treatment surface, the
LED system being arranged to emit radiation from the treatment
surface. The device can be arranged to provide irradiation to the
walls of the orifice, in which case the treatment surface may be an
outer circumferential surface of the housing. The treatment surface
preferably has a size and or shape selected for complimentary fit
with the treatment area, and is preferably sized to confront the
entire area where PDT is required. The LED lamp system and
treatment surface are preferably arranged such that radiation is
emitted toward the treatment area at sufficient proximity and
intensity to achieve the desired treatment effect.
[0038] The device may be arranged to provide irradiation to a
particular area of the inside of the orifice. Thus, the device may
include a treatment surface arranged to direct and/or focus
illumination onto a particular area of the inside of the orifice
when the device is in use. In one preferred embodiment the device
is adapted for use in PDT of the cervix. Therefore, preferably the
treatment surface is shaped so as to cover, in use, the opening of
the cervix. In this way, when the device is correctly inserted into
the vagina the treatment surface will cover the opening of the
cervix and hence enable the emitted light to irradiate the cervical
area.
[0039] The size of this treatment surface should be such that it
fits over the entire portio of the uterine cervix, e.g. 20-50 mm in
diameter, more preferably 20-35 mm in diameter and most preferably
22-30 mm in diameter.
[0040] Preferably, the treatment surface is at least partially
transparent so as to allow light from the LED to pass through the
surface to provide the required PDT treatment or diagnosis. In some
embodiments the treatment surface may be fully transparent to light
having the wavelengths required for PDT treatment and being emitted
by the at least one LED. However, preferably the material of the
treatment surface and/or other material between the treatment
surface and the light emitting portion(s) of the LED lamp system is
arranged to diffuse the light, thereby enabling an even
distribution of light from a number of LEDs. In one embodiment, a
transparent material is used to form both the housing around the
LED lamp system and also the treatment surface, thereby acting as
both a housing for the lamp system and a diffuser for the light. In
an alternative embodiment, a transparent material is used to form
the treatment surface while a non transparent material is used to
form the housing. This will ensure that only the area in need of
treatment is illuminated while other areas which get in contact
with the device are not subjected to irradiation.
[0041] Preferably, a transparent silicone is used as a material for
the treatment surface which acts as a diffuser for the emitted
light.
[0042] In some preferred embodiments the at least one LED may be
positioned on or extend out of the treatment surface. In such
embodiments it is not necessary for the light to pass through the
treatment surface and hence no constraints are placed on its
opacity.
[0043] In one preferred embodiment the treatment surface is
concave. This can assist in directing the emitted light towards a
treatment area, such as the cervix.
[0044] In embodiments designed for providing irradiation to the
cervix, the device comprises a protrusion which extends from the
treatment surface. Preferably this protrusion forms a cylindrical
tube. This can be used both to assist in the correct positioning of
the device within the vagina and also to direct light to the
cervical canal. In the latter case the tube acts as a light
tube.
[0045] Preferably the flexible outer portion is located to the rear
of the treatment surface. This prevents any interference with the
radiation treatment. In preferred embodiments in which the outer
portion is a continuous surface the outer portion can extend from
the treatment surface towards to rear of the device, tapering
outwards such that the widest section of the outer portion is
located rearwards of the treatment surface.
[0046] The device comprises a LED lamp system which is capable of
independent operation while the device is located within the
orifice.
[0047] The lamp system may comprise one LED or preferably an array
of LEDs. A particularly preferred LED array for PCT of cervix
comprises 3-15 LEDs. The term "LED" is intended to cover any form
of light emitting diode, for example OLEDs (organic light emitting
diode).
[0048] The energy consumption per unit time of the LED lamp system
should be such that the heating of tissue does not result in undue
discomfort or damage to the patient. The irradiation will in
general be applied at a dose level of 10 to 200 J/cm.sup.2, for
example at 50 J/cm.sup.2. The LED lamp system is therefore
preferably arranged to provide, in operation, a fluence rate in the
range of 0.5-100 mW/cm.sup.2, and most preferably in the range of
1-10 mW/cm.sup.2. This low fluence rate results in the total dose
being administered over a relatively long time period, e.g. several
hours. As mentioned above this is beneficial both in terms of
reduced discomfort to the patient and in the efficacy of the
treatment.
[0049] The wavelength of light used for radiation may be selected
to achieve an efficacious photodynamic effect and hence the LEDs
are selected for their ability to emit wavelengths of light
suitable for this effect. In one preferred embodiment the at least
one LED emits, in use, light having wavelengths in the range of
300-800 nm, for example, the range 500-700 nm has been found to be
particularly effective. It can be particularly important to include
the wavelengths 630 and 690 nm. Therefore preferably the at least
one LED emits, in use, light having wavelengths in the range of
630-690 nm. In a most preferred embodiment, especially if the
device is used together with a composition comprising a
photosensitizer precusor selected from 5-aminolevulinic acid or a
derivative, e.g. an ester thereof, red light (600-670 nm) is used
since light at this wavelength is known to penetrate well into
tissue. In some embodiments the LED lamp system comprises filters
to ensure that only light within a certain wavelength range, such
as those mentioned above, is emitted from the device. The treatment
surface may be designed such that only light having these preferred
wavelengths is transmitted.
[0050] The power source preferably comprises one or more batteries.
The batteries should preferably operate via electrochemical
reactions using chemicals that are not too toxic for the patient
should the device break or leak while within the body. Suitable
batteries include lithium batteries or equivalent of sufficient
capacity which may also be stored for up to 10 years. For example a
1/2 AA size LiMnO.sub.2 battery may be used. The slow loss of
charge and small size of lithium ion batteries makes them
particularly suited for use as the power supply for the device. In
order to increase the safety of the device, it is preferable that
the power source is sealed within the housing. By sealed it is
meant that the housing is fluid tight in use to prevent fluids
leaking into or out of the device.
[0051] At its most basic the lamp system can simply comprise
electrical connections for the power supply and an LED or LEDs.
With this arrangement, immediately prior to insertion of the device
the lamp system would be activated to switch on the one or more
LEDs. The device would then be inserted into the orifice where the
LED(s) will illuminate the treatment area until the device is
removed or the power supply is depleted.
[0052] Activation of the lamp system may be triggered by a switch.
In order to allow the device to be maintained sterile and to keep
the power source and other elements of the device enclosed, the
switch is preferably enclosed within the housing and arranged to be
operated whilst sealed within the housing. The switch may be a
mechanical switch located beneath a flexible part of the housing,
with operation of the switch being permitted by the resilience of
the flexible part. Alternatively the switch may be operated by
means of an electrical or magnetic field transmitted through the
housing. A magnetically operated switch may be implemented by the
use of a magnet outside the housing to hold a `normally closed`
reed switch open. When the magnet is removed the reed switch will
close and this can be used to activate the device.
[0053] In a simple system using just a power source and LED it is
hard to control the dosage level, as the precise life and power
output of the power supply will vary. In addition the illumination
provided by the LED array will be constant. In order to avoid
unacceptable heating of tissue, low intensity light is preferably
used and it may also be beneficial for the device to be able to
provide pulsed light.
[0054] Therefore preferably the lamp system further comprises a
control circuit, such as a microcontroller or microprocessor, for
regulating the irradiation provided by the at least one LED. The
control circuit of the lamp system may be activated by a switch as
described above. In a preferred embodiment the control circuit
comprises a timer. The lamp system can then be programmed to begin
illumination at a pre-determined time interval after activation.
This ensures that sufficient time has passed from activation to the
start of illumination. For example, in order to allow the
absorption or build up of porphyrins a certain time is required
after application of a photosensitiser or precursor drug. The
length of illumination can also be strictly controlled as the
control circuit can be arranged to switch off illumination after a
pre-determined dosage time has elapsed. To allow further build-up
of endogenous photo sensitizers (from precursors) after the first
illumination, the device may repeat the illumination (re-PDT) after
a certain period of time, e.g. 3 hours.
[0055] In addition the control circuit may be arranged to provide
pulsed illumination. This can be achieved by providing a function
generator within a microprocessor. As mentioned above, pulsed light
is advantageous in ensuring that no unacceptable heating of tissue
occurs. In addition, providing intervals in illumination enhances
tissue oxygenation and the effect of PDT. Further it allows for the
re-accumulation of endogenous porphyrins in surviving cells that
can be treated with repeated illuminations. The frequency and
length of the pulses can be chosen according to the requirements of
the treatment regime and set within the control circuit.
[0056] In one embodiment, the control circuit can be programmed by
the user. This enables the length, strength and illumination
pattern to be adjusted to suit individual treatments. Suitable
re-writable memory forms include EPROM, EEPROM, flash etc. However,
the control circuit memory is preferably read only (ROM) and
programmed at the time of manufacture.
[0057] Access to the control circuit could be achieved by means of
a user interface on the device. By answering a series of questions
the user can set the initial delay period, dosage duration, number
and length of light pulses etc. The interface may be integral with
the device. Thus, it may comprise small buttons that may be pressed
with a suitable tool or reed switches. Each button or switch may
activate a given pre-set condition such as light dose, intensity,
pulsed/steady light, etc.
[0058] It is important that all the electrical components of the
lamp system and power source are sealed within or to the housing
during use. Therefore the control circuit should preferably be
sealed within the housing. As mentioned previously the LED(s) could
be positioned such that these protrude from the housing. However,
preferably the LED lamp system is entirely sealed within the
housing during use.
[0059] In some embodiments the user interface may be accessible
through a flexible area of the housing. Alternatively the housing
may comprise an sealable opening which provides access to the
interface.
[0060] The provision of a user interface however increases the size
of the lamp system, which may be undesirable in certain
applications. Therefore, alternatively, the control circuit may
comprise a receiver for connection to a remote terminal. In this
way specific program commands can be communicated from the remote
terminal, e.g. a computer, to the control circuit.
[0061] In some embodiments the receiver comprises an input port
adapted for connection to a cable. In such embodiments the input
port is suitably shaped to receive, for example, a USB or other
male Connector.
[0062] The input port must be sealed during use. Therefore the
housing may comprise a plug for insertion into the port.
Alternatively the housing may consist of two components which can
be connected by means of, for example, screw threads, push or snap
fit connection or bayonet fitting. The connection comprises seals
in order to ensure that the control circuit is sealed within the
housing during use.
[0063] Alternatively the program commands may be transmitted to the
device by means of a wireless connection. For example, the receiver
may be an infra-red or radio wave receiver. This has the advantage
that a physical input port is not necessary and instead the control
circuit can be permanently sealed within the housing.
[0064] Preferably the control circuit further comprises a feedback
system. This enables the control circuit to make adjustments in the
treatment program to account for deviations in expected LED
performance.
[0065] For example, the feedback system may comprise a light
monitor or other direct or indirect monitor to measure the light
dose that has been given to the patient. In such systems the
control circuit may be programmed to switch off the LED(s) after a
pre-determined dosage has been reached rather than a pre-determined
time.
[0066] Alternatively the dosimeter may override the timer in the
event that the LEDs do not operate as expected. For example, if the
power supply is faulty the output of the LEDs may be reduced.
Therefore it will be necessary to continue illumination beyond the
pre-determined time in order to obtain a complete dose. Conversely
if the power output of the LEDs is stronger than anticipated the
illumination can be stopped ahead of the pre-determined time
interval, or the duration of each pulse can be shortened to prevent
overheating of tissue.
[0067] Another optional feature of the control circuit is one or
more performance indicator lights for informing a user whether the
device has operated correctly or whether a fault has occurred. The
control circuit may be arranged to provide a signal to the user
when treatment is complete to indicate that the device can be
removed. For example an acoustic and/or visual signal may be
provided, such as an alarm sound and/or a light signal.
Alternatively or in addition, a vibration could be used as the
signal to indicate the end of the treatment. Typically the patient
would be informed of the length of the treatment and so the signal
can be used to confirm an expected end of the treatment and hence
need not be overly intrusive.
[0068] Advantageously, as the control circuit may be used to turn
off the LEDs at the end of the treatment cycle there is no great
ill effect for the patient if the device remains inserted for
longer than the treatment time. However, it is expected that
patients will wish to know when treatment has ended and the device
can be removed.
[0069] Preferably some or all of the above mentioned features of
the control circuit are contained in a microprocessor.
[0070] Preferably the device further comprises a lens system
arranged to provide homogenous illumination over the treatment
area. The treatment surface may act as the lens system. For
example, this surface may be formed of silicone or another material
comprising surface elements for diffusing the light emitted by the
LED(s).
[0071] In use the device is preferably placed into the orifice by a
doctor, a nurse or another person with experience or education
within relevant fields. However, patients might in some situations
choose to insert the device themselves.
[0072] In one preferred embodiment the device comprises a handle at
its rear end. The handle can be used by the patient or medical
practitioner to firmly grip the device during insertion and
removal.
[0073] The handle may be an elongate arm extending from the housing
of the device. In a preferred embodiment however the handle is
arcuate in shape as smooth edges will prevent the possibility of
discomfort or damage to the patient. In some preferred embodiments,
the arcuate handle is attached to the device at two or more points
on the flexible outer portion. This is beneficial as, when the
handle is grasped and pulled, the flexible outer portion will be
pulled inwards, thus easing removal of the device. A similar effect
can be achieved by attaching a string or cord to at least two
positions on the outer portion, although this latter embodiment
will not assist in insertion.
[0074] Therefore preferably the device further comprises a removal
mechanism attached at two or more positions to the flexible outer
portion and comprising a central gripping portion.
[0075] Another option is for the device to be placed (and removed)
using a specific instrument, such as a pair of tweezers.
[0076] Advantageously, the device is designed for a single-use and
for disposal after that single use. Preferably, the device includes
one or more features that promote single-use and/or prevent repeat
use. For example, the power source may be arranged to provide power
that is only sufficient for a single-use, i.e. such that the power
source is depleted after the required treatment is complete. The
power source may be arranged so as not to be re-charged, and/or the
control circuit may lack access to re-charge the power source. The
control circuit may be arranged to prevent re-use by means of
features of its programming and/or it may include a deactivation
mechanism that destroys circuitry or software when triggered. To
prevent patient interference when in use, the control circuit may
also be arranged to selectively deactivate if interference is
detected. By enforcing single use patient safety is improved and a
strict control of sterility of the device is ensured.
[0077] The device of the present invention can be used to provide
PDT according to the following method. Firstly a composition
comprising a photosensitizer or precursor thereof is applied to the
area to be treated by a physician, where applicable by using a
specialised applicator, or the area of interest is treated by means
of a systematically acting drug. Such a systematically acting drug
may be supplied intravenously or orally, for example. The
programmed device is then switched on and inserted. The patient can
then immediately leave the medical facility and continue their
normal daily routine while the treatment area is receiving
illumination from the device. In this way treatment can occur over
a prolonged period of time without inconvenience to the patient.
This allows a low fluence rate to be used, increasing the efficacy
of the treatment. After the treatment is complete the patients can
either return to the medical institution for removal of the device
or remove it themselves. The device can either be discarded or
returned to the medical institution for disposal.
[0078] In a preferred embodiment the device of the present
invention further comprises a drug delivery system. The drug
delivery system may comprise a drug carrying area on the housing,
such as a drug carrying area on the treatment surface. This might
be a textured surface for carrying a composition of photosensitizer
or precursor or the treatment surface itself without any further
modifications may act as a drug delivering system. Alternatively,
the drug delivery system may comprise a reservoir for housing a
composition comprising a photosensitizer or precursor thereof
(hereinafter "composition").
[0079] The advantage of this embodiment of the present invention is
that the patient need not wait at the hospital for several hours
between application of the composition and illumination, as is
normal in existing PDT procedures. The device may automatically
perform the illumination either immediately upon application or
preferably at a later time. In addition, only one invasive
procedure is required.
[0080] Optionally the drug delivery system further comprises a
physical, mechanical or electrical system related to delivery. Such
an optional system may include, for example, filters, membranes,
one or more reservoirs arranged to deliver the photosensitizer or
precursor based upon a preset plan for drug delivery or based on
physical conditions, such as for example pH, osmolality,
temperature, pressure, water content in the surroundings. However,
the simplest and in most cases the most preferred drug delivery
system is just a single drug carrying area for housing the
composition, and in a most preferred embodiment, the drug delivery
system is the treatment surface itself.
[0081] In this preferred embodiment the method of use is similar to
that described above except that the composition is not applied to
the treatment area in a separate procedure. Instead the composition
is applied to the drug carrying area, e.g. the treatment surface,
and is hence applied to the body upon insertion of the device into
the orifice. Illumination is then conducted as described above.
[0082] The composition can be supplied together with the device. In
such instances the drug delivery system, i.e. drag carrying area or
reservoir, preferably treatment surface, may be supplied with a
cover, such as a foil or cap, to seal the composition within the
device until use. Prior to insertion the cover is removed so that
the composition can be released. Alternatively the device can be
supplied separately from the composition. This enables the
physician to choose the optimal composition for a particular case
and add this to the drug delivery system, i.e. drug carrying area
or reservoir, preferably treatment surface, prior to insertion.
[0083] The composition to be used with the device, whether in a
pre-filled device or applied to the device before use or applied to
the treatment area separately, may comprise any suitable
photosensitizer or precursor of a photosensitizer.
[0084] A range of photosensitizers are known in the scientific
literature. As discussed above, one type of such compounds are
compounds that per se are toxic to target cells or species or have
light emitting properties when exposed to light. Such compounds
have relatively large molecular weights and are often complex
molecules like phthalocyanines, chlorines, porphyrins or psoralens.
Another type of photosensitizers are compounds that not per se are
toxic or light emitting, but form such active compounds in vivo.
Such compounds--referred to herein as precursors--are typically
5-aminolevulinic acid (5-ALA) and derivatives of 5-ALA, like 5-ALA
esters. Either type of compound can be used or supplied with the
present device.
[0085] 5-aminolevulinic acid (5-ALA) and its derivatives are
amongst the most clinically useful precursors of photosensitizers
known in the art. These compounds are converted in the body to
protoporphyrin IX (PpIX), which is a photosensitizer that absorbs
light and in contact with oxygen generates singlet oxygen. Singlet
oxygen is extremely reactive and reacts fast with various cellular
biomolecules resulting in cell death.
[0086] 5-ALA and its derivatives are widely known and used in
methods of photodynamic therapy (PDT) for the treatment of various
abnormalities or disorders of the skin or other epithelial organs
or mucosa, especially cancers or pre-cancerous lesions, as well as
certain non-malignant lesions, e.g. skin diseases such as
psoriasis, actinic keratosis (AK) and acne. 5-ALA (Levulan.RTM.,
Dusa) and 5-ALA methyl ester (Metvix.RTM., Galderma, Switzerland)
are commercial therapeutic products for PDT treatment of actinic
keratosis and basal cell carcinoma.
[0087] The use of 5-ALA and derivatives thereof, e.g. 5-ALA esters
in PDT is well known in the scientific and patent literature (see,
for example, WO 2006/051269, WO 2005/092838, WO 03/011265, WO
02/09690, WO 02/10120 and U.S. Pat. No. 6,034,267). All such
derivatives of 5-ALA and their pharmaceutically acceptable salts
are suitable for use with the device herein described.
[0088] Esters of 5-aminolevulinic acid and N-substituted
derivatives thereof are preferred precursors in a composition for
use with the invention. Those compounds in which the 5-amino group
is unsubstituted, i.e. the ALA esters, are particularly preferred.
Such compounds are generally known and described in the literature
(see, for example, WO 96/28412 and WO 02/10120 to Photocure
ASA).
[0089] Esters of 5-aminolevulinic acid with substituted or
unsubstituted, preferably substituted, alkanols, i.e. alkyl esters
or, more preferably, substituted alkyl esters, are especially
preferred precursors in a composition for use with the
invention.
[0090] Examples of such precursors include those of formula (I) and
pharmaceutically acceptable salts thereof:
R.sup.2.sub.2N--CH.sub.2COCH.sub.2--CH.sub.2CO--OR.sup.1 (I)
wherein R.sup.1 represents a substituted or unsubstituted alkyl
group; and R.sup.2 each independently represents a hydrogen atom or
a group R.sup.1
[0091] As used herein, the term "alkyl", unless stated otherwise,
includes any long or short chain, cyclic, straight-chained or
branched saturated or unsaturated aliphatic hydrocarbon group. The
unsaturated alkyl groups may be mono- or polyunsaturated and
include both alkenyl and alkynyl groups. Unless stated otherwise,
such alkyl groups may contain up to 40 carbon atoms. However, alkyl
groups containing up to 30 carbon atoms, preferably up to 10,
particularly preferably up to 8, especially preferably up to 6
carbon atoms are preferred.
[0092] In compounds of formula I, the R.sup.1 groups are
substituted or unsubstituted alkyl groups. If R.sup.1 is a
substituted alkyl group, one or more substituents are either
attached to the alkyl group and/or interrupt the alkyl group.
Suitable substituents that are attached to the alkyl group are
those selected from: hydroxy, alkoxy, acyloxy, alkoxycarbonyloxy,
amino, aryl, nitro, oxo, fluoro, --SR.sub.3, --NR.sup.3.sub.2 and
--PR.sup.3.sub.2, wherein R.sup.3 is a hydrogen atom or a C.sub.1-6
alkyl group. Suitable substituents that interrupted the alkyl group
are those selected from: --O--, --NR.sub.3--, --S-- or
--PR.sub.3.
[0093] If R.sup.1 is a substituted alkyl group, one or more aryl
substituents, i.e. aryl groups, preferably one aryl group, are
preferred.
[0094] As used herein, the term "aryl group" denotes an aromatic
group which may or may not contain heteroatoms like nitrogen,
oxygen or sulphur. Aryl groups which do not contain heteroatoms are
preferred. Preferred aryl groups comprise up to 20 carbon atoms,
more preferably up to 12 carbon atoms, for example, 10 or 6 carbon
atoms. Preferred embodiments of aryl groups are phenyl and napthyl,
especially phenyl. Further, the aryl group may optionally be
substituted by one or more, more preferably one or two,
substituents. Preferably, the aryl group is substituted at the meta
or para position, most preferably the para position. Suitable
substituents include halo alkyl, e.g. trifluoromethyl, alkoxy,
preferably alkoxy groups containing 1 to 6 carbon atoms, halo, e.g.
iodo, bromo, chloro or fluoro, preferably chloro and fluoro, nitro
and C.sub.1-6 alkyl, preferably C.sub.1-4 alkyl. Preferred
C.sub.1-6 alkyl groups include methyl, isopropyl and t-butyl,
particularly methyl. Particularly preferred aryl substituents are
chloro and nitro. However, still more preferably the aryl group is
unsubstituted.
[0095] Preferred such R.sup.1 groups are benzyl, 4-isopropylbenzyl,
4-methylbenzyl, 2-methylbenzyl, 3-methylbenzyl, 4-[t-butyl]benzyl,
4-[trifluoromethyl]benzyl, 4-methoxybenzyl, 3,4-[di-chloro]benzyl,
4-chlorobenzyl, 4-fluorobenzyl, 2-fluorobenzyl, 3-fluorobenzyl,
2,3,4,5,6-pentafluorobenzyl, 3-nitrobenzyl, 4-nitrobenzyl,
2-phenylethyl, 4-phenylbutyl, 3-pyridinylmethyl, 4-diphenyl-methyl
and benzyl-5-[(1-acetyloxyethoxy)-carbonyl]. More preferred such R1
groups are benzyl, 4-isopropylbenzyl, 4-methylbenzyl 4-nitrobenzyl
and 4-chlorobenzyl. Most preferred is benzyl.
[0096] If R.sup.1 is a substituted alkyl group, one or more oxo
substituents are preferred. Preferably, such groups are
straight-chained C.sub.4-12 alkyl groups which are substituted by
one, two or three oxo groups. Examples of such groups include
3,6-dioxa-1-octyl and 3,6,9-trioxa-1-decyl.
[0097] If R.sup.1 is an unsubstituted alkyl group, R.sup.1 groups
that are saturated straight-chained or branched alkyl groups are
preferred. If R.sup.1 is a saturated straight-chained alkyl group,
C.sub.1-10 straight-chained alkyl group are preferred.
Representative examples of suitable straight-chained alkyl groups
include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl and
n-octyl. Particularly preferred are C.sub.1-6 straight-chained
alkyl group, most particularly preferred methyl and n-hexyl. If
R.sup.1 is a saturated branched alkyl group, such branched alkyl
groups preferably consists of a stem of 4 to 8, preferably 5 to 8
straight-chained carbon atoms which is branched by one or more
C.sub.1-6 alkyl groups, preferably C.sub.1-2 alkyl groups. Examples
of such saturated branched alkyl groups include 2-methylpentyl,
4-methylpentyl, 1-ethylbutyl and 3,3-dimethyl-1-butyl.
[0098] In compounds of formula I, each R.sup.2 independently
represents a hydrogen atom or a group R.sup.1. Particularly
preferred for use in the invention are those compounds of formula I
in which at least one R.sup.2 represents a hydrogen atom. In
especially preferred compounds each R.sup.2 represents a hydrogen
atom.
[0099] The most preferred precursors to be used in a composition
together with the devices according to the invention are compounds
of formula I and pharmaceutically acceptable salts thereof, wherein
R.sup.1 is C.sub.1-C.sub.6 alkyl, e.g. hexyl, more preferably
straight chain C.sub.1-C.sub.6 alkyl, e.g. n-hexyl and both R.sup.2
represent hydrogen, i.e. 5-ALA hexyl ester and pharmaceutically
acceptable salts thereof, preferably the HCl salts. The most
preferred precursor is 5-ALA hexyl ester and the most preferred
pharmaceutically acceptable salt of 5-ALA hexyl ester is the HCl
salt.
[0100] The composition comprising the photosensitizer or precursor
to be used together with the current device can be any type of
pharmaceutical formulation and may be prepared by any conventional
procedure available in the art (see WO 02/10120 to Photocure ASA).
For example, esters of 5-ALA may be prepared by reaction of 5-ALA
with the appropriate alcohol in the presence of base. Alternatively
compounds for use in the invention may be available commercially
(e.g. from Photocure ASA, Norway).
[0101] Preferred formulations are liquids (aqueous and
non-aqueous), solids such as dusting powder, tablets or
suppositories, semi-solids such as creams, ointments, gels or
pastes, foam formulations or other expandable formulations (for
example based on heating to body-temperature) and
formulations/systems similar to patches. The components in the
composition are the same components found in pharmaceutical
products on the market, and a listing of such components can be
found in handbooks of pharmaceutical excipients.
[0102] It is important that the formulation is a such that the
composition is absorbed completely into the tissue to be treated or
is transparent in order not to interfere with the illumination. As
noted above, it is also possible to make use of compositions that
are applied systematically, for example drugs that are given to the
patient intravenously.
[0103] Viewed from another aspect the present invention provides a
method of photodynamic therapy of a treatment area within an
orifice of the body, the method comprising: applying a composition
comprising a photosensitizer or precursor to the treatment area and
inserting an irradiation device according to the present invention
into the orifice, such that the LED lamp system of the irradiation
device operates to provide illumination to the treatment area.
[0104] The method may include a step of selecting a device of
suitable size and/or shape. The device may be selected firstly to
suit the orifice concerned, and secondly to suit different patient
conditions. For example, a device for treatment of the cervix would
preferably be selected from a range of sizes depending on the
patient's history of pregnancy.
[0105] The composition may be applied to the treatment area prior
to insertion of the device, and this may be done by directly
applying the composition, where applicable by using a suitable
applicator, or by means of a systematically applied drug, for
example a drug introduced intravenously into the patient. In an
alternative preferred embodiment the composition is supplied via a
drug delivery system of the device such that the steps of
application of the composition and insertion of the device occur
simultaneously. The drug delivery system may comprise a drug
carrying area or reservoir or may simply be the treatment surface
of the device, as discussed above.
[0106] Preferably the lamp system provides a dose level of 10 to
200 J/cm.sup.2, for example 50 J/cm.sup.2. The lamp system may have
features as discussed above.
[0107] The device can be provided separately from the composition
or with the composition already contained within a drug delivery
system. Alternatively the device could be provided in the form of a
kit comprising the device and at least one composition for use with
the device.
[0108] The present device and method for photodynamic treatment may
be combined with other therapeutic procedures, for example
administration of other therapeutic drugs. These therapeutic drugs
might be administered into the body prior to or together with
placing the device in the orifice or might be administered through
other routes of administration (e.g. oral, intravascular or
dermal). Typically such drugs include hormones, antibacterial
agents, antifungal agents, antiviral agents, anticancer agents or
combination of such drugs.
[0109] Although some of the preferred features of the invention
have been described in relation to providing PDT to the vagina and
cervix, it will be appreciated that these features device could
advantageously be included in devices for use in other body
orifices, such as devices for the rectum, ear or nose, as discussed
above. The present invention is not limited as to the particular
orifice that it is to be used in, but instead the invention
provides a device and method that can be beneficially used in the
treatment of various conditions in different orifices.
[0110] Several preferred embodiments of the present invention will
now be described, by way of example only, with reference to the
accompanying drawings in which:
[0111] FIGS. 1A and 1B show a perspective view and cross-section
respectively of a first preferred embodiment of an irradiation
device;
[0112] FIGS. 2A and 2B show a perspective view and cross-section
respectively of a second preferred embodiment of an irradiation
device;
[0113] FIGS. 3A and 3B show a perspective view and cross-section
respectively of a third preferred embodiment;
[0114] FIG. 4 shows a schematic diagram of a control circuit for
use in the irradiation device of the preferred embodiments;
[0115] FIGS. 5A and 5B show an isometric perspective view and
cross-section of a fourth preferred embodiment of an irradiation
device;
[0116] FIGS. 6A, 6B, 6C and 6D show a perspective view, side
elevation, end elevation and cross-section view of a fifth
preferred embodiment of an irradiation device; and
[0117] FIGS. 7A, 7B, 7C and 7D show a perspective view, side
elevation, end elevation and cross-section view of a fifth
preferred embodiment of an irradiation device.
[0118] FIGS. 1A and B show a first embodiment of an irradiation
device 10 for photodynamic therapy. The device 10 of the first
embodiment is arranged for use in photodynamic treatment of the
cervix. The device 10 comprises a flexible housing 1. The outer
portion 7 of this housing is approximately frustoconical in shape
and tapers outwards from the front end of the device to the rear.
The outer portion 7 is resilient such that in use this presses
against the walls of the vagina in order to securely hold the
device 10 in place.
[0119] Sealed within the housing 1 is a lamp system 12. This system
12 comprises an array of LEDs 5 and a control circuit 6. This
control circuit 6 will be discussed in more detail below. It
provides power to the LEDs 5 such that, in use, these will
illuminate the cervix.
[0120] The front end of housing 1 forms a treatment surface 2. This
treatment surface 2 is shaped so as to cover, in use, the opening,
of the cervix, thus ensuring that the illumination from the LEDs 5
is directed on to the treatment area. Treatment surface 2 comprises
a ring shaped contact surface 2a and a concave portion 2b.
Typically the contact surface 2a has a diameter of 20 to 50 mm.
[0121] In order to assist in the removal of the device 10, a string
4 is attached to at least two positions on the outer portion 7.
When the string 4 is grasped and pulled, the outer portion 7 is
drawn inwards, hence easing the removal of the device 10.
[0122] FIGS. 2A and 2B show an alternative embodiment of the device
20, which is also intended for use in the treatment of the cervix.
In this embodiment, the device 20 again comprises a resilient outer
portion 27 which is generally frustoconical in shape. In addition,
the treatment surface 22 is again formed of a ring shaped contact
surface 22a and a concave portion 22b. However, in this embodiment
only the control circuit 26 is sealed within the housing 21. The
LED array 25 protrudes into the concave portion 22b of contact
surface 22.
[0123] Further, the device 20 comprises an arcuate handle 23 which
extends from the rear end of the housing 21. Unlike the string used
in the first embodiment, the handle 23 of device 20 can be used to
assist in both the insertion and removal of the device.
[0124] A third embodiment of the device 30 is shown in FIGS. 3A and
3B. Once again, the main shape of the housing 31 and the outer
portion 37 remains unchanged.
[0125] The device 30 is similar in design to that of the device 10.
Both the LED array 35 and the control circuit 36 are housed within
housing 31 and a string 34 is provided to assist in the removal of
the device 30.
[0126] However, two important differences exist. Firstly, a
protrusion 38 extends from the treatment surface 32. This
protrusion 38 forms a drug delivery system and light tube through
which light from the LEDs 35 is directed. This protrusion 38 is
shaped so as to contact, in use, the cervical canal. The tube
allows the photosensitizes or precursor to be delivered to the
cervical canal (endocervix) as well as the light from the LEDs 35
and therefore increases the ability of the device 30 to provide
photodynamic therapy.
[0127] Further, the concave portion 32b of the treatment surface
acts as a reservoir within which a treatment composition 39 can be
housed. It can be seen that the concave portions 2b, 22b of the
previous embodiments would also be suitable for housing this
composition 39. In this way, the device of the present invention
can also act as a drug delivery device. The composition 39 contains
a photosensitizer or precursor suitable for photodynamic treatment
or diagnosis. By placing this composition 39 within the device
10,20,30, the composition can be applied to the treatment area upon
insertion of the device. In addition, delivery of the composition
to the cervical canal can be obtained by also coating the
protrusion 38 with the composition before inserting the device into
the patient. In this way the patient need only undergo one invasive
procedure before photodynamic treatment or diagnosis can be carried
out.
[0128] A control circuit suitable for use in any of the preferred
embodiments of the irradiation device is shown in FIG. 4. This
control circuit 40 takes power from lithium batteries 41 which are
used to power the LED array 45. The control circuit 40 comprises a
microprocessor 42, which controls the operation of the LED array
45.
[0129] For example, the microprocessor 42 can comprise a timer and
a memory into which can be programmed a dosage regime. The LED
array 45 can therefore be operated to illuminate the treatment area
for a predetermined length of time and can be arranged to operate
continuously or provide pulsed illumination. In addition the
control circuit 40 comprises a light sensor 43. This forms a
feedback circuit which enables the microprocessor 42 to adjust the
operation of the LEDs 45 to ensure that any abnormalities or
malfunction of the control circuit 40 do not affect the dosage
received by the patient.
[0130] Prior to the insertion of the device, a switch 46 is closed
to begin operation of the control circuit 40. This may, for
example, initiate timing of a "delay period", after which the
microprocessor 42 will begin operation of the LED array 45 in
accordance with the programmed regime. After a predetermined time,
or upon completion of a certain light dose (determined by light
sensor 43) the microprocessor 42 will switch off the LEDs 45. The
device can then be removed.
[0131] In modified embodiments the control circuit also comprises
two operation indicator lights (not shown). These may comprise two
LEDs, one of which is illuminated if the device has operated
correctly and a second LED which is illuminated if any malfunction
has occurred; combinations of lights may indicate specific faults.
Alternatively only a single operation indicator light may be
provided, which is illuminated upon completion of correct operation
of the device and which remains unlit if any malfunction has
occurred. The control circuit may incorporate an alarm device for
providing an audible signal, and/or a vibration device for
providing a signal by vibration.
[0132] This system alerts the patient and the medical practitioner
if any malfunction has occurred which has prevented the patient
from receiving the correct dosage. Signals from the control circuit
can also indicate that the treatment has been completed
successfully.
[0133] FIGS. 5A and 5B show a fourth embodiment of an irradiation
device, and in this embodiment the device is arranged for treatment
of the walls of an orifice of the human or animal body. The orifice
could be, for example, the vagina, rectum, ear or nose. The
particular size of the device and the specific shape can be varied
in accordance with the size and shape of the orifice.
[0134] The device includes a housing 51 that encloses an array of
LEDs 54 and a power supply and control circuit 55. The housing 51
of the illustrated embodiment is an elongate cylindrical shape with
a hemispherical end 52. This shape is a preferred shape for
insertion into the vagina and rectum, for insertion into other
orifices, a conical end (not shown) could be used in place of the
hemispherical end 52. A smaller device would be used for insertion
into the nose and typically the shape would be adjusted to be more
conical. For insertion into the ear a still smaller size and a
slimmer shape would be used. At the opposite end to the
hemispherical end 52 (or optional conical end) the device has a
loop 53 to aid insertion and removal and to attach a string, if
required.
[0135] The elongate cylindrical portion of the housing 51 includes
a treatment surface about its outer circumferential surface. The
treatment surface will contact the inside wall of the orifice in
order to provide illumination to a treatment area on the orifice
wall. To this end, the LED lamp system includes an array of LEDs 54
located about the elongate cylindrical portion beneath the
treatment surface. The LEDs 54 are arranged to provide illumination
through a cylindrical treatment surface. In modified embodiments,
LEDs may also be located underneath a treatment surface of the
hemispherical or conical end portion of the device. The housing 51
is made of transparent silicone, and this also forms the treatment
surface which may also act as a drug delivery system. The
transparent silicone acts as a lens that diffuses light emitted
from the LED array and hence acts to evenly distribute the emitted
light.
[0136] FIGS. 6A, 6B, 6C and 6D show a fifth embodiment of an
irradiation device 60 for photodynamic therapy. FIG. 6D is a
cross-section along line A-A on FIG. 6C. The device 60 of the fifth
embodiment is arranged for use in photodynamic treatment of the
cervix and has a housing 61 including an upper housing portion 61a
with features similar to the first and second embodiments, with the
addition of a lower cylindrical housing portion 61b extending
beneath the upper housing portion. The upper housing portion 61a is
flexible and includes an outer portion 67 that is approximately
frustoconical in shape and tapers outwards from the front end of
the device 60 to the rear. The outer portion 67 is resilient such
that in use this presses against the walls of the vagina in order
to securely hold the device 60 in place. The shape of the upper
housing portion 61a and its outer portion 67 can most clearly be
seen in FIG. 6D.
[0137] The LED lamp system 62 is sealed within the upper housing
61a, and has features similar to the embodiments discussed above.
The power supply for the lamp system is a battery 68 enclosed
within the cylindrical housing portion 61b. The battery is a 1/2 AA
size battery with the cylindrical housing portion 61b formed
relatively tightly around it. The control circuit 69 is also
enclosed with the battery, and advantageously this takes the form
of a PCB with a diameter the same as the battery diameter, for
efficient use of space.
[0138] The front end of the upper housing 61a forms a treatment
surface 63, which is a lens of transparent material covering the
LEDs of the LED lamp system 62. As with the fourth embodiment, this
material can be a transparent silicone which also forms the
remainder of the flexible housing of the device 60. An opaque white
silicone over-moulding can be used to cover the sides of the upper
housing portion 61a, both about the outer portion 67 and also on
the sides within the outer portion 67, and to completely cover the
cylindrical portion 61b. This white over-moulding acts as a
reflector for the lens of the treatment surface, and hides internal
parts in the cylindrical portion, which would include the battery
68 and control circuit 69. In one embodiment, the underside surface
of the housing portion 61a may be of black colour to protect the
vaginal mucosa which is not in need of treatment against the
emitted light.
[0139] The treatment surface 63 is shaped so as to cover, in use,
the opening of the cervix, thus ensuring that the illumination from
the LEDs is directed on to the treatment area. Treatment surface 63
comprises a contact surface 63a, which typically has a diameter of
22 to 30 mm. In a preferred embodiment, said contact surface 63a
acts as a drug delivery system, i.e. drug carrying area or
reservoir and carries a photosensitizer or a precursor.
[0140] At the base of the cylindrical housing portion 61b a loop 64
is provided to facilitate insertion and removal of the device. A
string can be attached to the loop 64, if required. Alternatively,
the loop 64 is missing and a string is attached directly to at
least two portions on the cylindrical housing portion 61b (not
shown).
[0141] A sixth embodiment of the irradiation device 70, which is
shown in FIGS. 7A, 7B, 7C and 7D. FIG. 7D is a cross-section along
line B-B on FIG. 7C. Irradiation device 70 has a housing 71
consisting of an upper housing portion 71a and a lower housing
portion 71b, wherein the upper housing portion 71a is similar to
the upper housing portion 61a of the device 60 of the fifth
embodiment. The upper portion 71a hence includes a generally
frustoconical outer portion 77, with a treatment surface 73 formed
by a contact portion 73a and a concave area within the truncated
top of the frustoconical portion 77. The outer portion 77 of the
sixth embodiment is shorter than the outer portion 67 of the fifth
embodiment, which represents an alternative way of forming the
device, and it should be appreciated that both of the fifth and the
sixth embodiment could be adapted to use either the shorter or
longer brim, each of which have different characteristics and
advantages. A loop 74 is provided in the sixth embodiment in a
similar fashion to the fourth and fifth embodiments. Alternatively,
the loop 74 is missing and a string is attached directly to at
least two portions on the lower housing portion 71b (not
shown).
[0142] The lower cylindrical housing portion 61b of the sixth
embodiment is replaced by an alternative lower housing portion 71b,
which takes the form of a generally triangular prism with its long
axis extending across a diameter of the upper portion 71a. The
triangular prism is arranged to house a 1/2 size AA battery placed
transversely across the device, instead of longitudinally in a
cylindrical section as in the sixth embodiment. The edges of the
prism are rounded for comfort. The control circuit 79 and LED lamp
system 72 are both located above the battery 78.
[0143] As with the fifth embodiment, the sixth embodiment can
include a white over-moulding to direct light to the treatment
surface 73.
[0144] As discussed above, with a device intended for treatment of
the cervix it is advantageous to provide different sizes since it
allows effective treatment for patients with different histories of
pregnancy. With the fifth and sixth embodiment, these different
sizes can be realised by adjusting the size of the upper portions
61a, 71a, as these portions act to secure the device within the
vagina with the treatment surface placed against the cervix. The
lower portion 61b, 71b, which houses the power supply, can be
manufactured in a single size, enabling a standardised arranged to
be used for the battery 68, 78 and control circuitry 69, 79.
[0145] The photosensitising composition for the photodynamic
therapy can be applied to the patient prior to insertion of the
device, either directly to the surface of the treatment area, or
systematically by intravenously or orally administered
compositions. Preferably, the composition is applied to the
treatment surface so that the photosensitising composition is
applied to the patient during insertion of the device. With
embodiments using a concave treatment surface, a photosensitive
formulation may be placed within the concave area providing a
reservoir of the formulation as discussed above. Alternatively, the
material of the device may be selected so that the required
photosensitive formulation will adhere to the treatment surface
sufficiently for transfer to the patient and the formulation can
then be simply applied in a layer on the treatment surface. For
example, with the device of the fourth embodiment a formulation can
be applied in a layer about the outside of the cylindrical
housing.
[0146] As will be appreciated, the device of the present invention
provides a convenient way for photodynamic therapy to be carried
out in any orifice of the human or animal body over long time
periods and at low fluence rates. This increases the convenience to
the patient and, in some cases, the efficacy of the treatment.
[0147] The embodiments described above are for illustration only
and should not be taken to limit the scope of protection. The
skilled man will appreciate that adjustments could be made to these
embodiments without deviating from the scope of the claims. For
example, the housing may be any shape which allows full and secure
insertion into the orifice and the exact shape of this housing will
depend on whether the device is intended for use on a human or
animal subject and on the orifice where the treatment is to occur.
In addition other forms of control circuit and LED array can be
used within the invention.
* * * * *