Induced hyperthermia in brain tissue: comparison between contact Nd:YAG laser system and automatically controlled high frequency current.

Concerning hyperthermia treatment, knowledge of time-temperature and of temperature distributions within tumour volumes is essential in order to obtain the maximal therapeutic effect. New techniques are developed to overcome these difficulties. Two different heat sources, the contact Nd:YAG laser system and the automatically controlled high frequency current are investigated. In a defined volume of 1 cm3, the laser system reaches 45 degrees C after 1.8 s exposure with 15 W output power. The high frequency current reaches 45 degrees C with 48 s exposition with 18.75 W output current. Both heat sources present an exponential decrease of the temperature profile depending on the distance and prove efficient for inducing anti-tumoural hyperthermia. The tissue heat clearance is compensated for by intermittent laser and high frequency current application.