title: Laser-induced hyperthermia: comparison of two different methods.
abstract: The effectiveness of two different techniques of laser-induced hyperthermia was analyzed in healthy piglet livers. Hyperthermia was produced using a continuous-wave Nd:YAG laser with both a contact sapphire probe and a bare quartz fibre. In both methods the tip was inserted into the liver, and the temperature 1 cm from the tip was raised and held between 42 degrees C and 44 degrees C for 600 seconds. Specimens were taken 0, 7 and 14 days after the treatment. The tissue effects of 36 treatment sites were analysed using standard van Gieson's method. In addition, a histochemical method for demonstrating lactate dehydrogenase activity was employed to show damage not observable by routine methods. No statistically significant difference in the extent of the treatment sites at d 0 and after 7 days was seen when comparing the two laser methods. After 2 weeks, the diameter of the lesion with the bare fibre was significantly larger (3,7 mm with both analysing methods) than by using the contact probe (2,6 with LDH demonstration; P < 0.01 and 2.1 mm with van Gieson's staining; P < 0.001). It can be concluded that the simple fibre tip seems more effective in causing tissue necrosis than the sapphire tip.
mesh_terms: D000818:Animals; D006979:Hyperthermia, Induced / Q000295:instrumentation / Q000379:methods*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007834:Lasers; D008099:Liver / Q000201:enzymology / Q000473:pathology*; D009336:Necrosis; D012016:Reference Values; D013194:Staining and Labeling; D013552:Swine
chemical_list: D007770:L-Lactate Dehydrogenase