TREATMENT APPARATUS

Abstract

A treatment apparatus for treating a skin lesion on skin of a patient, the apparatus comprising a source of electromagnetic radiation (16), a guide (6, 20) to guide the electromagnetic radiation to the skin lesion (25) and a control apparatus (1), the control apparatus (1) being arranged so as to cause the source (16) and the guide (6, 20) to: provide an initial burst of electromagnetic radiation to the skin lesion (25) to heat it to a first temperature selected by the control apparatus (1); cease providing electromagnetic radiation to the skin lesion (25) for a period; and provide a further burst of electromagnetic radiation to the skin lesion (25) so as to maintain the temperature of the skin lesion within a temperature range selected by the control apparatus (1). The apparatus may comprise a temperature sensor (24) which detects the temperature of the patient’s skin, typically the skin lesion.

Claims

1. A treatment apparatus for treating a skin lesion on skin of a patient, the apparatus comprising a source of electromagnetic radiation, a guide to guide the electromagnetic radiation to the skin lesion and a control apparatus, the control apparatus being arranged so as to cause the source and the guide to: a) provide an initial burst of electromagnetic radiation to the skin lesion to heat it to a first temperature selected by the control apparatus; b) cease providing electromagnetic radiation to the skin lesion for a period; and c) provide a further burst of electromagnetic radiation to the skin lesion so as to maintain the temperature of the skin lesion within a temperature range selected by the control apparatus; in which the period is at least 1 second and the source of electromagnetic radiation comprises a laser.

2. The treatment apparatus of claim 1, in which the first temperature is at least 45, 50 or 55 degrees centigrade, and at most 57, 59, or 60 degrees centigrade.

3. The treatment apparatus of claim 1, in which the temperature range has lower and upper bounds; the lower bound being between 50 and 57 degrees centigrade, or between 53 and 56 degrees, or 55 degrees ± 1 degree centigrade; the upper bound being between 58 and 61 degrees, typically 60 degrees ± 1 degree centigrade.

4. The treatment apparatus of claim 1 in which the period is between 1 and 30 seconds, typically 15 and 20 seconds.

5. The treatment apparatus of claim 1, in which the control apparatus is arranged to repeat steps b and c at least once, and preferably a plurality of times.

6. The treatment apparatus of claim 1, in which the initial burst comprises a series of a plurality of pulses.

7. The treatment apparatus of claim 1, in which the guide comprises a beam steering apparatus to direct the initial and/or further bursts over the patient’s skin.

8. The treatment apparatus of claim 1, comprising a source of a visible light aiming beam, to help the user position the initial and further bursts on the skin lesion.

9. The treatment apparatus of claim 1, in which the control apparatus is arranged so as to be configured by the user to control the guide to deliver a series of pulses over a target area so that heat energy is delivered uniformly over the target area and not outside it.

10. The treatment apparatus of claim 1, comprising a temperature sensor which detects the temperature of the patient’s skin, typically the skin lesion.

11. The treatment apparatus of claim 10, in which the control apparatus is arranged to calibrate the skin response to treatment by causing the source of electromagnetic radiation to deliver a calibration burst which is smaller than required to reach the first temperature, and to measure, using the temperature sensor, the resulting temperature increase and rate of cooling.

12. The treatment apparatus of claim 11, in which the control unit is arranged to so as to determine at least one of a fluence of the initial and further bursts and the period based upon the temperature increase and the rate of cooling.

13. A method of treating a skin lesion on skin of a patient, the method comprising: a) using a laser to provide an initial burst of electromagnetic radiation to the skin lesion to heat it to a predetermined first temperature; b) ceasing providing electromagnetic radiation to the skin lesion for a period of at least 1 second; and c) providing a further burst of electromagnetic radiation to the skin lesion so as to maintain the temperature of the skin lesion within a predetermined temperature range.

14. The method of claim 13, comprising using a treatment apparatus for the method of treating a skin lesion on skin of a patient, the apparatus comprising a source of electromagnetic radiation, a guide to guide the electromagnetic radiation to the skin lesion and a control apparatus, the control apparatus being arranged so as to cause the source and the guide to carry out steps a) - c), wherein the predetermined first temperature and the predetermined temperature range are selected by the control apparatus.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] There now follows, by way of example only, description of an embodiment of the invention described with reference to the accompanying drawings, in which:

[0044] FIG. 1 shows schematically an apparatus in accordance with an embodiment of the invention;

[0045] FIG. 2 shows the effect on the temperature of a patient’s skin of the use of the apparatus of FIG. 1;

[0046] FIG. 3 shows the relationship between fluence of each burst and temperature increase of the patient’s skin; and

[0047] FIG. 4 shows different cooling rates for different patient’s skin.

DETAILED DESCRIPTION

[0048] A treatment apparatus in accordance with an embodiment of the invention is shown in FIG. 1 of the accompanying drawings. This comprises a computer 1, having a processor 2 and storage 3 (such as a mass storage device or random access memory) coupled to the processor 2. The storage 3 contains data and processor instructions which cause the processor 2 to act as is described below. The computer 1 can be any suitable model; typically a personal computer running an operating system such as Microsoft (RTM) Windows (RTM) or Apple (RTM) Mac OS X (RTM) can be used. The computer 1 is also provided with a display 4 controlled by the processor 2 on which any desired graphics can be displayed, and a sound output device 15 such as a buzzer which can sound an alert noise.

[0049] The apparatus further comprises treatment device 5 having an associated handheld probe or handpiece 6. The treatment device comprises two sources - a visible light source 17 and a treatment source 16 creating a visible light beam and a treatment beam respectively. These are both coupled to probe 6 through hollow articulated arm 20 with beam-steering optics in the joints which direct collimated light from the laser sources to the probe (although in an alternative a fibre-optic cable, optical waveguide or other beam directing and transmission means can be used). The probe has a stand-off 10 which spaces the probe 6 from the subject’s skin 7.

[0050] Typically, the treatment source 16 can be any of a Nd:YAG laser, a Diode laser, a Pulsed Dye laser, a CO.sub.2 laser, a Thulium laser, a Holmium laser and an Alexandrite laser.

[0051] The probe 6 also has a beam steering apparatus formed within (typically comprising at least one rotating mirror), which can steer the beams as they are provided through the arm 20 throughout the field of view of the camera.

[0052] The user can then input the treatment area, which will typically include a skin lesion 25. This can be done, for example, using the methods set out in our UK Patent application number 1919208.7 or PCT application PCT/GB2020/053278, the contents of which are hereby incorporated by reference. Alternatively, any convenient method of indicating area to be treated can be used.

[0053] After imaging the treatment area and calculating the treatment area and matching treatment spot pattern, the beam steering mechanism will direct the visible low-intensity aiming beam to rapidly trace out the spot pattern. Thus, the user will have visible confirmation of exactly where the treatment will be delivered. If for some reason, it is not correct, then the user can take appropriate action such as adjusting the treatment settings. Only when the user is satisfied that the visible low-intensity aiming beam is tracing out the correct area can the treatment itself be instigated by use of a foot pedal 21.

[0054] In order to provide the treatment of the skin lesion 25, a series of pulses are provided. The effects of this can be seen in the graph shown in FIG. 2 of the accompanying drawings. This shows the temperature of a skin lesion 25 with time.

[0055] In time period 100, an initial burst of EM radiation is provided to the skin lesion. This has the effect of bringing the temperature of the lesion from about 35 degrees centigrade (close to body temperature) to around 48 degrees centigrade. The initial burst then stops in period 101, and the skin lesion 25 cools by a few degrees.

[0056] Further bursts in periods 102, 104, 106 and so on keep the temperature within a range indicated at 110. Pauses 103, 105 and 107 and so on each allow the skin lesion to cool after a respective further burst.

[0057] The temperature increase due to each burst shows a simple relationship with the fluence of the burst in question, as shown in FIG. 3 of the accompanying drawings, for some sample skin. This shows an effectively linear relationship between temperature increase and fluence. However, the exact relationship will vary from patient to patient.

[0058] Likewise, cooling rates can vary from patient to patient, as shown in FIG. 4 of the accompanying drawings, which shows the skin of two differently-sized patients cooling from roughly the same starting point.

[0059] As such, it could be possible for the processor to predict from patient characteristics the heating and cooling characteristics of the patient’s skin. However, as an alternative, it may be desirable to transmit a calibration burst — not enough to reach temperatures which would have a therapeutic effect — and determine using a temperature sensor 24 (such as a focussed IR temperature sensor) both the temperature increase that that caused, and the rate at which the patient’s skin cools afterwards. The computer 1 can then use these data to determine the fluence, duration and separation of the bursts.