Skin Treatment Apparatus And Method

Abstract

A method and system for aesthetic skin treatment. The system includes a treatment energy source for generating a treatment beam and a treatment beam deflecting mechanism configured to direct the treatment beam to a treated skin area. One or more video cameras configured to capture a treated skin area and communicate captured treated skin area image to a processor. Based on a captured treated skin area the processor constructs a three-dimensional representation of the captured skin area and controls a treatment energy beam deflecting mechanism to deflect the treatment energy beam to follow the three-dimensional representation of the captured skin area.

Claims

1. A system comprising: at least one treatment energy source for generating a treatment beam; at least one treatment beam deflecting mechanism configured to direct the treatment beam to a treated skin area; at least one video camera configured to capture a treated skin area and communicate captured treated skin area image to a processor; and a processor configured to construct, based on a captured treated skin area a three-dimensional representation of the captured treated skin area and wherein the processor is further configured to control a treatment beam deflecting mechanism to deflect the treatment beam to follow the three-dimensional representation of the captured skin area.

2. The system according to claim 1 further comprising an infrared imager configured to capture an infrared image of the treated skin area captured by the at least one video camera and communicate the infrared image of the treated skin area to the processor and wherein the processor is also configured based on the infrared image of the treated skin area to assess at least temperature of adipose tissue located below the treated skin area.

3. The system according to claim 1 wherein scanning angle of the treatment beam is less than 30 degrees and wherein treatment beam intensity roll-off is less than 10 percent.

4. The system according to claim 1 further comprising a treatment beam intensity roll-off look-up table and wherein based on the treatment beam intensity roll-off look-up table the processor adjusts a deflected treatment beam intensity.

5. The system according to claim 1 wherein the processor controls a treatment beam deflecting mechanism to produce a plurality of treated skin area scanning patterns and wherein the processor also controls a treatment beam scanning speed.

6. The system according to claim 1 wherein treatment beam intensity and scanning speed are selected to support temperature of adipose tissue located below the treated skin area at least 40 degrees Celsius.

7. The system according to claim 1 wherein a treatment beam intensity varies along a scanning angle.

8. The system according to claim 1 wherein the treatment energy source delivers treatment energy in a continuous or pulsed mode.

9. The system according to claim 1 wherein a temperature sensing device is a non-contact temperature measuring device.

10. The system according to claim 1 wherein the treatment beam deflecting mechanism is at least one of a group of elements consisting of a flat mirror, concave mirror, holographic element and a rotating polygon.

11. The system according to claim 1 wherein the scanning treatment beam forms a scanning spot on the treated skin area and wherein the processor maintains treatment beam scanning speed to maintain an overlap of at least 30% between two neighbor treatment spots.

12. The system according to claim 1 wherein a treatment beam scanning speed is set to match a thermal relaxation time and perfusion rate of a targeted skin.

13. The system according to claim 1 wherein a treatment beam scanning speed is set according to size of the treated area and desired temperature to be maintained.

14. A method of skin treatment, comprising: providing at least one treatment energy source for generating a treatment beam; employing a scanning mechanism to scan the treatment beam across a three-dimensional skin area to be treated; employing a temperature sensing device configured to sense a temperature of the skin area to be treated; and using a processor configured based on the temperature of the skin area to assess at least the temperature of adipose tissue located below the skin area to be treated.

15. The method according to claim 14 further comprising using the processor to control a treatment beam scanning mechanism and movement of scanning system, treatment beam location, treatment beam intensity and treatment beam operation time.

16. The method according to claim 14 wherein the processor is controlling the scanning mechanism to produce a plurality of skin area scanning patterns and wherein the processor is also controlling a treatment beam scanning speed.

17. The method according to claim 14 wherein selecting treatment beam intensity and scanning speed is to support temperature of adipose tissue located beneath the skin area to be treated at least 40 degrees Celsius.

18. The method according to claim 16 wherein based on temperature of surface of currently treated 3D skin area the processor is controlling a scanning mechanism to produce a plurality of 3D skin area scanning patterns to maintain the currently treated skin area at least 40 degrees Celsius.

19. The method according to claim 15 wherein the processor is controlling the scanning mechanism to produce a plurality of skin area scanning patterns and wherein the processor is also controlling a treatment beam scanning speed.

Description

LIST OF FIGURES AND THEIR BRIEF DESCRIPTION

[0018] FIG. 1 is an example of an existing skin treatment laser scanning system;

[0019] FIG. 2 is a schematic illustration of a skin treatment energy delivering scanning system according to an example;

[0020] FIG. 3 is a schematic illustration of an image displayed on the display of the present system for skin treatment according to an example;

[0021] FIG. 4 is an example illustrating dependence of incident electromagnetic radiation beam fluence as a function of the incident angle on a turbid media;

[0022] FIG. 5 is an example illustrating dependence of the electromagnetic energy beam fluence distribution as function of the incident angle in the XZ plane;

[0023] FIG. 6 is an example illustrating dependence of the electromagnetic radiation beam, such as a laser beam, penetration depth into a turbid media as function of incident angle;

[0024] FIG. 7 is a schematic illustration of an example of skin temperature distribution when it is irradiated by a treatment energy radiation;

[0025] FIG. 8 illustrates an example of a cryogenic cooling device for cooling large skin area; and

[0026] FIG. 9 is an example of a workflow of the skin treatment by the present system for skin treatment.

DESCRIPTION

[0027] Currently, most of the skin treatments by electromagnetic energy and in particular by light are performed by an applicator that when applied to the skin affects an area of 33 mm.sup.2 and up to 3030 mm.sup.2. In order to treat other skin segments or areas, the applicator is repositioned or re-aligned across a large segment of the skin and activated to deliver or couple tissue or skin affecting or treatment energy to this segment of skin. Proper skin treatment and in particular adipose tissue treatment for circumference reduction would provide better results if efficient, homogenous affecting energy delivery over a relatively large skin areas or segments could be performed.

[0028] It has been found that it would be advantageous to affect simultaneously or almost simultaneously a large skin area without involving hand motion and applicator repositioning by the caregiver.

[0029] The present disclosure suggests an efficient, homogenous and almost simultaneous skin treatment energy delivery apparatus and method over a relatively large skin areas or segments of skin. Treatment energy beam scanning provided by a deflecting mirror or a rotating polygon supports almost simultaneous delivery of the skin treatment or skin affecting energy across a large area of skin. Overlap of the scanning spot formed by the treatment energy beam along the scanning path removes non-uniformities caused by any none-uniform energy distribution or hot-spots in the treatment energy beam pass. Application of treatment energy by scanning the treatment energy beam makes the skin treatment less dependent or almost not dependent on the caregiver's expertise and reduces the treatment time considerably.

[0030] An additional advantage of the treatment energy beam scanning is that it supports variability in position of the scanning spot in all three dimensions/axes. Treatment energy beam spot could be easily positioned at almost any location on the skin in X-Y plane and also moved over relatively large distance in direction of Z axis or depth.

[0031] The need to accurately identify the temperature readings or representation of target tissue temperature across the treated skin area under such conditions may represent a serious challenge to any caregiver. The present document also discloses a method of target tissue temperature determination in course of the skin treatment.

[0032] As light energy is absorbed rapidly when penetrating the skin, heating of the superficial layers of the skin is inevitable. In order to eliminate the risk of undesired harmful effect of the epidermis and dermis one may use a number of cooling methods such as contact cooling, dynamic-cooling, air-cooling, cryogenic cooling and other known in the art cooling methods. These epidermal protection methods cool the skin in any combination of before, during and after the delivery of light energy to the skin. So the temperature rise within the epidermal and dermal layer is below the threshold of harming the tissue, while still reaching desired treatment temperature in the targeted tissue.

[0033] Monitoring the temporal change of the skin temperature could be done by using a thermal camera, IR temperature sensor, ultrasound propagation speed temperature monitoring, contact temperature sensors, non-contact temperature sensing device, or any other means that can be used to assess the temperature in the target tissue. This could be achieved by measuring the amount of heat that has dissipated from the target to the skin and then cooled by either normal air convection of the skin or by taking into account the temporal dynamics of bio-heat equation for the entire treated skin area.

[0034] Another advantage of using a scanning treatment energy beam is the ability for continuous control of a large number of variables available in course of the skin treatment. This could include distribution of energy in each of wavelengths of the treatment radiation beam, the spot/area formed by irradiating the skin treatment beam, overlap between two neighbor treatment spots, treatment energy level, exposure duration per unit area or continuous irradiation, selected treatment duration and adaptation to treated skin/tissue area characteristics.

[0035] In some examples, the energy dose delivered by a scanning treatment beam spot could be set to cause immediate detectable temperature rise of the treated tissue. In other examples of the method and apparatus disclosed, the energy dose delivered by a scanning treatment beam spot could be set to cause a slow, immediately not detectable temperature rise of the treated tissue, such that the treated and surrounding tissue is heated but not damaged.

[0036] The scanning system could deliver the treatment energy in a continuous or pulsed mode. Uniform scanning treatment beam intensity or fluence distribution and location on the treated skin area among others could be regulated by processor 218 (FIG. 2) that maintains treatment beam scanning speed to facilitate an overlap of at least 30% between two neighbor treatment scanning spots.

[0037] In a further example, the treatment beam scanning speed could be set to match the thermal relaxation time and perfusion rate of the targeted skin/tissue, such as dependent on the size of the treated area and desired temperature to be maintained, or a homogenous desired skin temperature is maintained for a certain volume of targeted tissue.

[0038] Reference is made to FIG. 1 which is an example of an existing skin treatment laser scanning system. Skin treatment system 100 includes a treatment energy source 104 that provides a treatment radiation beam 108. Treatment radiation beam 108 impinges on a treatment beam deflecting or scanning mechanism 112 that could be one or more of flat or concave deflecting mirrors, a scanning polygon, a holographic disk and a combination of the above. A control module 116 controls position of the scanning mechanism 112 and is configured to locate treatment scanning spot 120 at any coordinate in X-Y scanning plane 124. System 100 could also include a lens 128 that could be a flat field lens or a regular lens or lens array depending on the length or angle of the treatment beam scanning and the depth profile of the treated skin. In some examples lens 128 could be a beam expander\reducer matching the spot size on the skin with a treatment plan or protocol.

[0039] When treatment energy beam 108 is directed to scan across the skin the actual spot size produced by the treatment beam intensity may change due to change in the incidence angle and the skin curvature at any location on skin, the fluence of the treatment energy changed in order to compensate and reach the desired treatment energy intensity by temporarily increasing the source power.

[0040] FIG. 2 is a schematic illustration of a skin treatment system according to an example. Skin treatment system 200 includes a treatment energy source 204 that is configured to generate a treatment radiation beam 208. Treatment radiation or treatment energy source 204 could be a semiconductor optical energy source such as laser diode, VCSEL, an assembly of laser diodes or bars, a solid state laser, a fiber laser, or other laser energy source with suitable power and wavelengths. Treatment energy source 204 could operate at wavelength of visible to NIR (450-2000 nm) and provide treatment energy radiation power of 1 W to 17 kW. The treatment energy source 204 in FIG. 2 can be a broad spectrum light source of either coherent or non-coherent radiation such as a Xe, Kr, W, Quartz-Iodine lamps or a LED. Treatment radiation beam or simply treatment beam 208 impinges on a treatment beam deflecting mechanism 212 that could be one or more deflecting mirrors, a scanning polygon, a holographic scanning system and a combination of the above. In one example, the treatment beam deflecting mechanism 212 could be a two dimensional beam deflecting or scanning mechanism, In a further example, the treatment energy beam deflecting mechanism 212 could deflect the treatment beam along one axis X or Y and a linear movement or displacement of the treatment beam deflecting mechanism could be used to scan in the other direction.

[0041] A computer 216 that includes a processor 218 which controls position of the scanning mechanism 212 and is configured to locate treatment beam scanning spot 220 at any coordinate in scanning plane 224. Processor 218 also controls the scanning mechanism 212 to produce a plurality of treated skin area scanning patterns and further controls the scanning speed of treatment scanning spot 220 and treatment energy source operation time. Control module 216 and in particular processor 218 controls all elements of system 200 including operation time and parameters of treatment energy source 204. It has been noted above that the human or animal skin usually has a three-dimensional contour or profile. In one example, system 200 includes a dynamic focus module 228, such as HPLK or Pro-series module, commercially available from Cambridge Technology, Inc., Bedford, Mass. 01730 U.S.A. However, in the current disclosure the Dynamic Focus Module (DFM) is used to follow the three-dimensional contour or profile of the human skin and not to flatten the X-Y plane. In order to compensate for any change in the curvature of the skin and deliver the prescribed fluence or power dose, the treatment radiation beam divergence could be changed. The change in divergence would cause a change in the spot size and changes to the treatment radiation intensity delivered by the scanning spot could be introduced. By changing treatment radiation beam 208 divergence, the diameter of the scanning spot 220 could be changed up to ten times or even more. The diameter of spot 220 could change for example, from 5 to 30 mm.

[0042] The scanning or treatment energy beam sweep angle and 3D (three dimensional) nature of human body distort to certain degree the scanning treatment spot shape and cause a treatment beam intensity roll-off at peripheral treatment beams. Scanning treatment energy spot shape distortion could be compensated among others by changing the size of the scanning spot and/or the amount of fluence delivered into the treatment energy radiation beam. The amount of fluence or intensity delivered into the treatment radiation beam could be compensated by providing a treatment intensity roll-off look-up table or by calculating the change in energy in real-time. Based on the treatment intensity roll-off look-up table processor 218 adjusts the deflected treatment energy beam intensity to maintain a roll-off the treatment energy beam intensity or fluence of less than 10% (10 percent). The look-up table is calculated based on the skin 3D contour and the treatment energy beam incidence angle that is usually less than 30 degrees. The scanning system could deliver the treatment energy in a continuous or pulsed mode. Uniform scanning treatment radiation beam distribution on the treated skin area among others could be regulated by processor 218 (FIG. 2) that maintains treatment beam scanning speed to facilitate an overlap of at least 30% between two neighbor treatment scanning spots.

[0043] System 200 further includes a 3D acquisition system 232 (For example, video cameras 232-1 and 232-2) configured to capture a treated skin area or segment and communicate the captured treated skin area image to processor 218. The 3D acquisition system 232 also communicates the captured image or images to processor 218, which based on the communicated image or images is configured to reconstruct/determine the three-dimensional (3D) contour of the treated segment or area of the human body. The 3D acquisition system 232 could be equipped with an optical zoom system supporting imaging of different sizes of the treated skin area or segment. Processor 218 is also configured to construct based on the captured skin area a three-dimensional representation or topography of the captured skin area. Processor 218 is further configured to control the treatment energy beam deflecting mechanism to deflect the treatment energy beam to follow the topography or three-dimensional representation of the captured skin area.

[0044] System 200 further includes one or more infrared (IR) cameras or imagers 236 configured to provide processor 218 with a thermal image of the skin affected by the treatment energy radiation. Infrared imager 236 could be almost any infrared camera supporting temperature sensitivity of 1 K or better. Infrared imager supports non-contact and non-invasive skin temperature measurement. IR imager or camera 236 could have a resolution sufficient to support imaging of an area of the treated skin segment with dimensions of 3030 cm.sup.2 or smaller. Processor 218 is configured to receive the thermal image indicating temperature distribution on the surface of the currently treated by the treatment energy beam skin segment and determine the temperature of the currently treated skin area or segment. Physical properties of human tissue are known and relatively well established. Temperature distribution below the skin surface can be calculated based on skin surface temperature and finite elements analyses, using the Bio-heat equation or other suitable numerical and statistical methods known for solving the different heat distribution equations.

(For Bio-heat equation details see H. H. Pennes, Analysis of Tissue and Arterial Blood Temperature in the Resting Human Forearm, J. Appl. Phys. vol. 1, pp. 93-122, 1948 and incorporated in its entirety in the present description.)

[0045] Methods of assessing temperature inside the body by analyzing the radiation reflection spectrum or any other known in the art method could be used to assess temperature of the adipose tissue located below the skin. Real-time temperature monitoring facilitates safe and effective skin treatment.

[0046] Imager or infrared camera 236 could be equipped by an optical zoom system supporting imaging of a large area or segment of the treated skin or a small area of the treated skin segment.

[0047] System 200 further includes a display 240. Processor 218 based on the signals received from the infrared imager 236 continuously or at predetermined intervals updates the displayed thermal image of the treated skin segment. Based on the signals received from the 3D acquisition system 232, processor 218 issues corrections to the treatment energy spot and treatment energy beam location to follow the skin contour.

[0048] Display 240 is configured to receive from processor 218 the thermal image of the treated skin segment and to display the temperature of the skin segment or thermal map 300 (FIG. 3) of the treated by the skin treatment energy skin segment. Display of the image captured by the 3D acquisition system facilitates visual control of the process by the caregiver. The image provided by 3D acquisition system 232 could include area larger than the treated skin areas and include surrounding the skin treatment area skin segments.

[0049] FIG. 3 is a schematic illustration of an image displayed on the display of the present system for skin treatment according to an example. Image 300 shows area 304 with a homogenous skin temperature that could be a desired treatment temperature. Areas 308-316 illustrate segments of skin having temperature different from the desired treatment temperature. The temperature could be higher or lower than the desired treatment temperature and each area 308-316 could have a different temperature.

[0050] Display 240 is also configured to receive from computer 218 processor 216 (FIG. 2) the thermal image of the treated skin segment and the current or most recent location of the scanning treatment energy spot 220, within the treated by the skin treatment energy skin segment.

[0051] In some examples control of the treatment process and of the scanning system could be simplified by forming a specific scanning geometry, for example, limiting the treatment energy beam incidence angle to 20, 15 or 10 degrees. At such treatment energy beam incident angles, scanned treatment energy power is almost constant and skin topography does not change significantly.

[0052] FIG. 4 is an example illustrating dependence of incident electromagnetic radiation beam fluence as a function of the incident angle on a turbid media. The electromagnetic radiation could be a laser beam. Turbid media was simulating human tissue or skin and was produced/simulated by different concentration of milk in water. The figure (FIG. 4) shows that in highly concentrated turbid media at incidence angles from 0 degrees to about 30 degrees the fluence of the laser beam does not significantly change.

[0053] FIG. 5 is an illustration of the incident electromagnetic energy beam fluence distribution in the XZ plane (in the depth of the turbid media) at different electromagnetic energy beam incident angles. The electromagnetic energy beam had a radius R=8 mm. The crosshatched area is an area with maximal electromagnetic energy beam fluence. The fluence distribution pattern does not manifests visible asymmetry.

[0054] FIG. 6 is an example illustrating dependence of the electromagnetic radiation beam, such as a laser beam, penetration depth into a turbid media as a function of incidence angle. The figure clear shows that for incidence angles ranging from 0 (zero degrees) to about 40 (degrees) the penetration depth of the laser beam into a turbid media is weakly dependent on the laser beam incidence angle.

[0055] In FIG. 4 and FIG. 6 solid line marks measured values and round dots mark calculated values. Experimental results have been obtained using a Nd:YAG (532 nm) and a laser diode (800 nm) electromagnetic radiation.

[0056] FIG. 7 is a schematic illustration of an example of skin temperature distribution when it is irradiated by a treatment radiation. Treatment radiation scanning beam scans the skin surface from which the treatment energy penetrates into deeper skin layers and heats for example, hair roots, adipose tissue and collagen. Prolonged heating, for example 30 to 50 min of the target skin areas (e. g. hair roots, adipose tissue) and maintenance of the target areas at a constant relatively low skin temperature of for example, 40 degrees Celsius, causes the desired skin treatment effect. The effect could be hair removal, adipose tissue reduction, wrinkle reduction and other. As it has been illustrated in FIG. 3 some skin areas could have a temperature higher or lower than the desired treatment temperature. Skin areas with higher temperature could be cooled.

[0057] FIG. 8 illustrates an example of a cryogenic cooling device for cooling large skin area. Cryogenic cooling device includes two bars 804 and 808 (FIG. 8A-8B) spaced apart with a plurality of nozzles through which cryogenic gas or cold air, schematically shown in FIG. 8C by arrows 812, is directed to skin surface 816. Treatment energy radiation 820 is directed into space 824 between bars 804 and 808. Bars 804 and 808 could move in a synchronous or asynchronous movement mode following the treatment radiation beam and changing width of space 824 between bars 804 and 808. Bars 804 and 808 could be of straight shape or a have a type of arched or curvilinear shape (FIG. 8C) to approximate the shape of the treated skin area.

[0058] FIG. 9 is an example of a workflow of the skin treatment by the present system for skin treatment. Initially, operator or caregiver sets the desired treatment beam fluence (Block 904). Proper fluence values could be achieved by setting treatment radiation power from 1.0 W to 10 kW. Concurrently treatment radiation pulse duration is set to be 1 msec to 1 sec or CW operation. At block 908 the operator determines topography or 3D profile of the scanned surface. Given the topography of the scanned surface, it is possible to set the distance from the deflection module to the treated skin segment (Block 912). The operator sets the treatment radiation power and other treatment radiation parameters to meet the change in the distance to the treated skin segment (Block 916). In some examples in addition to change in the distance to the treated skin segment treatment changes to beam divergence or focal length of lens 128 also could take place. Changes in beam divergence or focal length could control the size of the scanning spot 220 (FIG. 2) formed by the treatment beam. Spot 220 could change from 5 to 30 mm. Upon completion of the settings a video camera 232 could be used to validate (Block 920) the distance to the treated skin surface.

[0059] According to another example, control of the distance between the scanning mechanism and the treated skin surface could be performed based on the dimensions/size of the treated body. Image sensors, such as video cameras 232 (FIG. 2) could be adapted to provide the desired information to processor 218 that would execute a proper algorithm supporting determination of the dimensions/size of the treated body.

[0060] In some examples the treatment process settings and control could be simplified by using prepared ahead of time standard skin treatment procedures parameters. The procedures could be stored in the memory as a Look-up-Table (LUT) of computer 216 (FIG. 2), which controls the process of the skin treatment.

[0061] While the method and apparatus have been particularly shown and described with references to some examples thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the method and apparatus encompassed by the appended claims.