Evaluation of the effect of interstitial laser hyperthermia on experimental subcutaneous tumours

The technique of interstitial laser hyperthermia using a Nd-YAG laser and a frosted artificial sapphire probe has been evaluated in rat liver. This showed that 3W is capable of producing hepatic necrosis at a temperature of 42.5–44C at 5 mm from the probe. This information has been applied to the treatment of two experimental subcutaneous tumours of contrasting morphology: a Yoshida Sarcoma; and HSN Fibrosarcoma. Using 3W, 1200s and 4W, 900 s, tumour necrosis was produced and 50% of the HSN Fibrosarcomas were completely eradicated if their peripheral temperature was at least 43C for 900 s.