Infrared Imaging for Laser-Therapy Monitoring

The application field that attracted a great deal of attention has been the medicine since the birth of the laser. From the beginning it was considered as a very potential and promising tool for several different application in medicine. Nevertheless nobody could have imagined at that time the development and the enormous effect of its use in so many different sectors of medicine ranging from surgery to oncology, from urology to ophtalmology, from ginecology to dermatology, from physiotherapy to aesthetic medicine. Nowadays the use of laser has become a very common practice in all the medicine sectors and with different pathologies. These pathologies have been cured thanks to the use of different laser sources, selected as a function of both wavelengths and power, and to more and more sophisticated technologies. We can just think to very complicated surgery operation which are performed in a successful way with the help of laser-scalpel, or to skin tumours treated with coherent light, to operation with laser endoscopy which is now the common practice, to get up to aesthetic, ophtalmology, and dermatological operations, and so on. Dermatology is one of the medical field in which laser action has been succesfully employed. Deseases like skin melanoms and angioma are usually treated with laser theraphy. In this field, during the last decades, technology supplied laser sources with technical properties specifically designed in order to accomplish the specific requirements of several application. Nowadays dermatologists can rely on a wide range of lasers which vary in wavelengths (some of them out of the visible range) and thus they can be selectively employed according to the specific application and type of pathology. The activity of the doctor consists in applying the laser light for a specific time and with a fixed intensity in the area of interest of the skin of the patient. After, he verifies the effects induced by the light laser after one or two weeks time. The physician usually makes use of the laser on his patient in an empirical way. Basically, just according to his own experience he decides the duration of the application and the intensity of laser light on the skin according to some parameters such as the individual patient, the pathology and the skin phototype. In most of the treatments what happens is that the doctor has no possibility to directly evaluate the effect of the laser applied on line since the wavelength of it is not in the visible range or it is pulsed. This means flashes of few milliseconds too fast to be recorded by the eyes. This limits the operation of the doctor because the beam power chosen might be too low or too high on one side or the duration of the pulse too short or too long respectively. The information comes only after a few days or weeks later to the physician. And this seems to be the only remarkable limit in the application of laser in dermatology. It is important to underline that the doctor should always work under a safe regime for the patient. This means that he has to avoid damages like scars which might occur since he has no direct vision of the interaction light-treated tissues and so he usually prefers working with a lower intensity of light. This aspect, on one side means a safer situation for the patient but on the other side minimize the efficacy of the therapy making the cure time longer. The possibility to give to the doctor a tool which makes him able to monitor on-line the reaction of the skin during the laser application (and not just examining the post application effects) means: 1- To enhance the performances of the light effect enlarging remarkably the application fields 2- To optimize the action in itself in terms of both efficiency and curing times. In phototherm