Evaluation of the Ar+ laser thermal effect in rabbit brain tissue by means of optical absorption coefficients. Photoacoustic measurements

Prediction of the interaction effects Ar+ laser-brain tumours by study of the photoacoustic spectroscopy of cerebral oncotypes

A preliminary definition of light absorption spectra of brain neoplasm represents a correct approach to the laser therapy of cerebral tumours. The goal should be the identification of those oncotypes more sensive to the laser energy, allowing consequently a dosage of the energy proportional to the light absorption coefficient, reducing any side effects. With this purpose the coefficients of light-absorption of 63 different brain tumours have been analyzed and defined by means of photocoustic spectrometry. The study has been focused at wavelength of the Ar+ laser (4,600-6,000 A). The results show a close relationship between histology, degree of vascularization and/or pigmentation and light absorption: the more immature and/or pigmented oncotypes show the highest coefficients of optical absorption. In the laser therapy of these neoplasms it will be sufficient to use low powers and short exposure time.