After the advent of the low noise microwave amplifier called MASER an intensive research started to employ the same method for light amplification, the LASER. A paper published in 1958 demonstrated the principle but only in 1960 the goal of a functional laser was reached by Th. Maiman. His ruby laser was the first device being able to produce visible laser radiation. Among the numerous applications of lasers, laser medicine is certainly the one with the most direct impact on humans. We will review the mostly unknown history of the development of the first laser and the beginnings of laser medicine and then outline present day importance of the laser light source for medical application and discuss future possibilities.

We will present an overview of some new optical diagnostic techniques that have emerged in the past few years. Among those: *Photon Transillumination of Tissue. Pulsed or modulated laser light is scattered and/or absorbed in tissue. The position of scattering layers and discrete absorbers will influence the pattern of light emerging from inside. Image analysis will reveal those positions. *Photoacoustics of Tissue. Not the emerging light but ultrasound waves, produced by adiabatic heating (approximately 1 K) of blood cells by absorption of laser photons, are detected at the surface. The relatively low sound velocity allows to perform time-of-flight measurements, thus enabling to obtain depth-sensitive information. *Laser Doppler Monitoring and Imaging. On one hand the traditional monitoring technique is being upgraded in a large-scale European Standardization project. On the other, new imaging techniques are emerging. Also, laser-Doppler using self-mixing techniques renders flow information from inside arteries.

Aim: To evaluate the safety and efficacy of an 808 nm diode laser for the treatment of benign facial pigmented and vascular lesions, with and without the use of an exogenous chromophore. Method: Thirty-eight patients were treated with an 808 nm diode laser (Eufoton, Italy), in some cases using a chromophore (1% methylene blue, SALF, Bergamo). Pigmented lesions: 21 patients, (15 pigmented keratoses, 6 melanoses). All the lesions were evaluated by dermatoscopy (Videocap 200, DS Medica, Italy) before the treatment. Fluence levels were 10 - 30 J/cmq; pulse lengths were 10 - 50 ms; spot size was 2 mm. Five hypopigmented keratoses were artificially pigmented using exogenous chromophore. Two melanoses required an additional laser session. Vascular lesions: 17 patients, (12 small angiomas, 5 teleangectasias). Fluences were 50 - 100 J/cmq; pulse lengths were 10 - 50 ms; spot size was 2 mm. Eight angiomas were pigmented with exogenous chromophore prior to the treatment. In all cases the areas surrounding the lesions were cooled. The patients were followed at 1, 4 and 8 weeks after the procedure. Results: The keratoses healed completely within two weeks. Four melanoses healed after four weeks. In the two melanoses that were re-treated after eight weeks there remained slight hypopigmentation of the area. All the vascular lesions healed after 15 days without any residual scarring. Considerations: The use of the 808 nm diode laser in the treatment of benign facial pigmented and vascular lesions appears to be justified on the grounds of efficacy and safety of the device, and good degree of acceptance by the patients. By increasing absorption of the 808 nm beam and reducing its penetration, the pigmentation of superficial lesions with exogenous chromophore allowed us to decrease fluences and reduce irradiation times.

The detailed statistical analysis of the tissue fluorescence spectra was proposed for the investigation of tissue biochemical changes. The method is based on the decomposition of the autofluorescence spectrum into the spectra of natural components of cells. The human tissues with different physiological activity or affected by sickness were investigated. The tissue spectra changes are grouped by the histology data. The observed correlation of fluorescence spectra structure changes for cancer and other 'normal' phases of the tissue are observed from multivariate statistical analysis.

The aim of this paper is to present the fundamentals of good practice when using the laser in medicine and surgery. As a 'good practice' recommendation, the laser beam wavelength and power should be determined to match the desired thermal effect. The energy losses to the surroundings of the initial absorbing volume, caused by the heat diffusion mechanism, are strongly dependent on the exposure time duration. The differences in the absorption and scattering coefficients of some tissue components are used for selectively destroying those components having the higher absorption coefficients. Selective destruction of some tissue components can be achieved even for components having the same absorption coefficient but different dimensions. The laser therapy strategy is discussed: the effective use of lasers in medicine can be achieved only if the physician has an extensive understanding of the laser-tissue interaction mechanisms; continuing education and training is a must for laser surgeons to improve their skill to get clinically optimal results.

A collaboration of the laser physicist and aesthetic surgeons has started 10 years ago. Within the period 1992 - 2000 we have carried out the investigation of the influence of the pulsed radiation, emitted by lasers having as active mediums crystals of the aluminum-yttrium garnet and alexandrite, on the cultures of the alive tissue and the fibrosis capsules around foreign bodies in the animals. Besides, we have studied the clinical protocol: in majority, patients were women after mammary augmentation. The laser tatoo non-invasive removals were marked at the beginning of the pulse of the Q-switch neodymium yttrium-aluminum garnet laser radiation used in human. It was obtained that this laser radiation broke the cell proliferation without any mutations and morphology changes. It was also noticed much evidence that the high functional fibroblast activities were registered in fibrosis capsules of not exposed animals to the laser radiation. It was also noticed that the use of laser radiation affected the speed and quality of the productive inflammation. The softening of the fibrous capsule around the mammary implant and the reduction of the pronounced rubbers were the clinical effects of the laser radiation.

For prophylaxis and treatment, the pulsed solid state neodymium yttrium-aluminum garnet laser was used. It has been shown that this kind of radiation inhibits the proliferative process and prevents the scar hyperfibrotization. In this paper author's reports about the development of the method for improving the scar quality using Nd:YAG laser are presented.

Two classes of substances which may be used in the treatment of malignant tumors in ophthalmology are studied from the point of view of their spectroscopic properties: synthetic porphyrines such as TNP, TPP, TSPP and Zn-TSPP and cytostatics such as 5-fluorouracil. The absorption, excitation and fluorescence spectra of the porphyrins are measured in water and DMSO solutions to allow their efficient use in photodynamic therapy studies at irradiation with UV-laser light. A spectroscopic study of 5-fluorouracyl, a cytostatic drug used in the treatment of ophthalmologic tumors is reported. Absorption, fluorescence excitation/emission spectra were measured for solutions of 5-fluorouracyl at 5 X 10^-5 M concentration. The effects of UV-VIS irradiation of on the 5-fluorouracyl solutions were investigated. The irradiation was performed with a classical Xe lamp having a power density of 11 mW/cm², at time intervals between 15 min and 60 min. While the absorption is not affected by light irradiation, the fluorescence of the solutions is increasing with the irradiation duration.

Among macular diseases, choroidal neovascularization (CNV) is one of the most common causes of visual loss, especially in the form associated with age-related macular degeneration and pathologic myopia. Research on these diseases has recently evaluated new treatment modalities that use laser light differently; among these, photodynamic therapy (PDT) has been introduced in the clinical practice, allowing us to expand the possibility of reducing visual loss in patients affected by CNV. With PDT, a photosensitizer (verteporfin, Visudyne^TM) is injected intravenously, and it selectively binds to new vessels; low-power laser light exposure then activates the drug, leading to oxidative damage of the endothelium and new vessels thrombosis. Yet, other therapies, such as transpupillary termotherapy, or the use of photocoagulation to cause feeder-vessel occlusion, could proof effective, but they need further investigation.

Our studies on the facial nerve of the rabbit are concerned with the development of a laser system by means of which tissue can be removed in the immediate vicinity of nerves without causing functional damage to the nerves. The risk of mechanical damage to nerve tissue, which inevitably occurs through pulling and through pressure in conventional surgery, is minimized by touch-free use of the laser. The basic necessary examinations involved bathing the freshly removed facial nerve from rabbit specimens in a nutrient medium inside a specially developed 'organ chamber' which enabled the nerve to be kept alive for many hours. Using successive laser treatment with pulse intensities of up to 100 mJ the laser spot was gradually approached from a lateral angle or radially through a small agarose plate and the electrical activity registered at the respective pulse intensity. The nerve and the conducting electrode were located in the organ chamber on a carriage which could be perceptibly shifted. In this way it proved possible to accurately record the position of the laser treatment for the histological examination. Our studies showed that an individual pulse of only 15 mJ striking the peripheral area of the facial nerve was sufficient to generate a clearly perceptible total action potential. A necessary precondition is, however, that a conducting electrode is placed directly over the nerve fiber bundle which is being irradiated. During conduction of the total action potential there is no observable transfer to the neighboring fiber bundle.

A spectroscopical characterization of methotrexate, cytostatic drug used frequently in cancer therapy, was performed. The absorption, emission and excitation spectra were measured for methotrexate solutions in natural saline and sodium hydroxide at concentration in the range 10^-5 M -10^-6 M and pH 8.4. The absorption bands are noticed in the spectral range 250 nm - 450 nm. The fluorescence excitation was made at 340 nm and 370 nm; the fluorescence emission was detected in the spectral range 400 nm - 500 nm with a maximum at 450 nm. The behavior of absorption and fluorescence spectra of methotrexate solution exposed to uv-visible light was investigated. The irradiation was made using an Xe lamp (emission between 325 nm and 420 nm and power density of 11 mW/cm²). The exposure time was between 15 min. and 3 h. Major modifications on absorption bands for irradiation times longer than 1 hour were observed. Furthermore, the methotrexate solutions become strongly fluorescent after irradiation. The observed changes are not linear with the exposure time indicating complex photochemical processes which implies, at least, one intermediate product.

A lot of people, overall athletic one suffer from tendinitis or complete rupture of the Achilles tendon. This structure becomes inflamed and damaged mainly from a variety of mechanical forces and sometimes due to metabolic problems, such as diabetes or arthritis. Over the past three decades extensive studies have been performed on the structural and mechanical properties of Achilles tendon trying to explain the constitutive equations to describe and foresee tendon behavior. Among the various mechanical parameters, the vibrational behavior is also of interest. Several investigations are performed in order to study how the Achilles tendon vibrations influence the response of the muscle proprioception and human posture. The present article describes how in vitro tensile experiments can be performed, taking into account the need to simulate physiological condition of Achilles tendon and thus approaching some opened problems in the design of the experimental set-up. A new system for evaluating tendon vibrations by non contact techniques is proposed. Preliminary simple elongation tests are made extracting the main mechanical parameters: stress and strain at different fixed stretches, in order to characterize the tissue. Finally, a vibration study is made at each pretensioned tendon level evaluating the oscillating curves caused by a small hammer.

The introduction of Ho:Yag laser has brought many advantages in urology. By this work we want show you our experience with this technology. Between April 1998 and May 2000 we treated 137 patients. Of these 28 had urinary lithiasis (18 bladder and 10 ureteral stones 3 in the upper, 2 in the middle and 5 in the distal tract), 40 were affected by enlargement of prostatic gland: 32 had B.P.H., 8 P.C.; 36 had T.C.C. and 33 strictures of urethra (27) or bladder neck (6). For ureteral lithiasis we used 200 micrometer fiber, energy of 0.5 - 1.4 J with 10 Hz of frequency. In case of bladder stones a 550 or 1000 micrometer using a power of 80 W. The prostatic gland were resected by a 550 micrometer fiber, 2.2 - 2.8 J, 25 - 30 Hz and 70 -80 W. The superficial bladder tumors were removed by 1.4 J with 10 - 15 Hz and 10 - 14 W. In the large tumors we completed the procedure by Nd:YAG at the base of the tumor. Urethra and bladder neck strictures were treated by 1.2 - 1.8 J and 10 - 30 Hz. We successful treated 26 patients with urinary lithiasis obtained the complete vaporization of the stones, 2 had endoscopic ancillary procedures. Out of 32 patients with B.P.H. 41% had the complete resection of the gland the others the resection of the 3d lobe. We removed 114 superficial bladder tumors and only 4 patients had a local recurrence. Of the patients with the strictures 4 had more than one treatment and about 87% had good result. From our experience the use of Holmium:Yag laser has been very efficacy to treat different urological diseases, also in patients with important comorbid disorders and its use reduce the stay in hospital and so the costs.

A brief introduction of the main effects on the tissue produced by the laser beams is made with emphasis on the lasers applications in bronchology. Author's experience on the application of lasers in bronchology is synthesized outlining the results obtained by using a Nd:YAG flexible fiberoptic bronchoscope in bleeding and relieving air way obstruction by tumors or strictures.

The purpose of our work is to evaluate any statistically significant difference between different types of lasers using the treatment schedule. In the years 1980 - 1996 we used lasers 904 - 10,600 nm together on patients affected by many rheumathologic diseases. Since 1997 we started to use 810 nm laser. In 1998 we used always lasers 904 - 10,600 in a group of 26 patient affected by chronic fibromyositis. The results were positive, but the same pathology appeared again on the same patients after two years (year 2000), and we treated half group of 13 patients with laser 810 nm. The other half group of 13 patients with the same pathology and the same relapses was treated again with lasers 904 - 10,600 nm during the year 2000. The same density energy and fluence has been applied. From a mathematical and physical point of view there should not have been any difference, whereas from the biological and clinical point of view the result has not been the same.

Laser acupuncture (LA) has been utilized as a combined approach of Chinese traditional acupuncture and low-level laser therapy since its emergence in 1973. Its mechanisms are not well understood and the standardization of clinical protocols has not been established. In this study, we used a diode laser to irradiate on four acupuncture points for normal subjects to investigate the effect of LA. For each point, the irradiation lasted for three minutes. The median nerve conduction velocity was measured within a 30 minutes interval at day 1, day 5, and day 10 respectively. Patients with chronic carpal tunnel syndrome (CTS) were given LA therapy for three stages at most with a one-week interval between two stages. Treatment outcome measurements included patients' subjective feedback (McGill pain questionnaire, VAS) and objective measurements (physical examination, kinesiological properties and NCSs). It was a randomized single-blind controlled trial. For normal subjects, motor nerve fiber was sensitive to LA and the motor conduction velocity was decreased very significantly (p < 0.001). Besides, it was found that LA resulted that sensory nerve conduction velocity was decreased significantly when it was measured 30 minutes after the subject had received LA application. For CTS patients, the outcomes except pinch test indicated that LA could improve patient's conduction. These results suggested that LA could cause the change of nerve conduction.

To compare the effectiveness of the two therapeutic approaches, ultrasound and low level laser (LLLT) used in 181 patients suffering from calcar calcanei-plantar fasciitis. The effectiveness of the treatment was determined according to the evaluation of the patient using certain criteria described in the table. The complete disappearance of pain was seen in 50% of 60 patients treated with US and partial improvement in 16.6% and 69 patients were treated with LLLT from which 67% described complete pain relief, and 20% partial improvement. The results show that the LLLT is a good therapeutic approach in the treatment of pain in patients suffering from calcar calcanei-plantar fasciitis. The treatment with laser was significantly more successful then the ultrasound therapy, which is currently the most common therapy used for plantar fasciitis.

Objective: The evidence in medical literature is that a beneficial analgesic effect can only be obtained by employing laser radiation of relatively low power density and wavelengths which are able to penetrate tissue. For this reason the semiconductor, or laser diode (GaAs, 904 nm), is the most appropriate choice in pain-reduction therapy. Summary Background Data: Low power laser (or LLL) acts on the Prostaglandins synthesis, increases the endorphins synthesis in the Rolando gelatinous substance and in the dorsal horn of the spinal cord. The L-Arginine, which is the classic substrate of nitric oxide, carries on vasodilatory and anti- inflammatory action. Methods: Treatment was carried out on 447 cases and 435 patients (250 women and 185 men) between 20th May 1987 and 31st December 1999. The patients, whose age ranged from 25 to 70, were suffering from rheumatic, degenerative and traumatic pathologies as well as cutaneous ulcers. The majority of patients had been seen by orthopaedists and rheumatologists and had undergone x-ray, ultrasound scan, etc. All patients had previously received drug-based treatment and/or physiotherapy, with poor results. Two thirds were experiencing acute symptomatic pain, while the others presented a chronic pathology with recurrent crises. We used a pulsed IR diode laser, GaAs emitting at 904 nm. Frequency of treatment: 1 application per day for 5 consecutive days, followed by a 2-day interval. The percentage reduction in symptoms or improvement in functional status were determined on the basis of objective analysis as it happens in the Legal and Insurance Medicine field. Results: Very good results were achieved especially with cases of symptomatic osteoarthritis of the cervical vertebrae, with sport-related injuries, epicondylitis, osteoarthritis of the knee, periarthritis and with cutaneous ulcers. The beneficial action of the LLLT in the latter pathology is linked to the increase in collagen and to fibroblast proliferation. The total relief of the pain was achieved in 80% of acute and 65% of chronic cases. Conclusions: Treatment with 904 nm IR diode laser has substantially reduced the symptoms as well as improved the quality of life of the patient, thus postponing the need for surgery.

We used laser therapies for viral hepatitis since 1993 and for HIV-patients since 1995. For these purposes we developed the special infrared laser and proposed some schemes of laser action on organism. Our laser works in pulse-periodical regime on the wavelength 890 nm with an average power of laser radiation (10 divided by 60) mW. All laser action was produced transcutaneous only. We did not observe any side effects or negative results from laser therapy with our laser. The treatment of viral hepatitis was produced by means of irradiation a blood in cubital veins, liver and thymus (breast bone area). Laser therapy was produced both on the usual base and disintoxical therapies. More than 300 viral hepatitis patients had received the laser treatment and for the most of them it gave a positive results. The treatment of HIV-patients was produced by means of irradiation six areas of their organism, which are responsible for immune system work. All our HIV-patients (25 men) who received laser treatment live up to now.

A short review about the elementary processes which characterize the laser beam interaction with the tissues, of interest in low level laser therapy is made. Author's comments about the spreading of the laser radiation within the tissue, function of the modal structure and other parameters are presented. Author's proposals about the evaluation of the low level laser therapy results are reported, based on their experience in the clinical treatment of some diseases using low energy laser beams emitted in red and near infrared. Particular comments are introduced about the use of electromyography (EMG), electroneurography (ENG) and cutaneous ultrasound (US) in connection with the objective measurement of the results obtained in the treatment with low energy/power laser beams.

Photodynamic therapy is a treatment that is used for destruction of certain tumors. The treatment is performed with photosensitizers that generate reactive oxygen species in the presence of light and oxygen. The absorption and fluorescence spectra of the ClAlPcS₂ and ZnPcS₂ photosensitizers were measured. From this analysis a semiconductor laser emitting a beam of 50 mW cw power at the wavelength of 675 nm for our experiments was chosen, because this wavelength corresponded with the absorption maximum (675 nm) in long-wave region of the visible part of electromagnetic spectra. B16 (cells line of mouse melanoma) was chosen as a standard testing system for definition of the in vitro phototoxicity after photodynamic reaction. The optimal phototoxic effect on B16 cells was observed at 2 (mu) g/ml ClAlPcS₂ in combination with laser irradiation of 10 J/cm².

Keloid scars trouble the patients particularly for aesthetical reasons. They also frequency result in various functional disturbances, they are painful and the patient suffers for dysesthesia on touch. Low level laser is able to provide three principal effects: biostimulating, analgesic and antiinflammatory. Particularly thanks to the first two effects we are able, when adhering to the proper therapeutic procedure, to moderate or even remove the above mentioned problems. We complement the low level laser treatment by applications of ointments, cremes or silicone strips. Our communication is aimed at a case report concerning the treatment of keloid scars resulting from an injury by a jellyfish with the aim to familiarize the reader with wide therapeutic possibilities of non-invasive laser, even in indications which are not frequently encountered in central Europe.