Coagulation and temperature distribution in Nd: YAG interstitial laser thermotherapy: an in vitro animal study.

Interstitial laser thermotherapy (ILTT) was performed increasingly for local destruction of different tumours. The proposal of the present study was the optimisation of the therapy-relevant ILTT parameters and laser application forms which are a prerequisite for the development of an optimal tumour treatment strategy. Laser-induced temperature changes and coagulation patterns with different laser light applicators (bare fibre, ring mode fibre, side fibre, diffuser fibre) were investigated on liver, spleen and tongue tissues of 26 adult pigs after interstitial thermotherapy with Nd: YAG laser. Analysis of experimental results on ILTT and tissue necrosis showed a dependence on laser exposure time, type of laser fibre and applied laser energy. The most homogeneous and extensive coagulation zone was seen after laser treatment with rather low energy over a longer time period.