Interstitial laser-induced thermotherapy: Influence of carbonization on lesion size

✍ Scribed by Sturesson, Christian

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 152 KB
• Volume: 22
• Category: Article
• ISSN: 0196-8092
• DOI: 10.1002/(sici)1096-9101(1998)22:1<51::aid-lsm12>3.0.co;2-b

✦ Synopsis

Background and Objective:

The size of laser-induced coagulated lesions produced in porcine muscle in vitro using a cylindrical diffusing fiber tip and a conductive heat source, made by covering the diffuser with a hollow steel needle, were compared to investigate the influence of charring. Materials and methods: Light from a Nd: YAG laser was utilized for thermotherapy. A theoretical model for calculating tissue temperature was used to predict the experimental results and to simulate in vivo treatments. Results: The metal-covered tip produced carbonization and tissue vaporization that was not found with the diffuser. After 20 min of irradiation at a laser power of 7 W, the coagulated volumes with and without carbonization were found to be 13.1 cm 3 (range 12.4-14.1 cm 3 , n = 4) and 12.2 cm 3 (range 11.5-13.4 cm 3 , n = 4), respectively. Mathematical simulations showed that in unperfused tissue, a diffusing laser heat source produces smaller lesions than does a conductive heat source at the same power, the difference in coagulated volume becoming smaller with increased treatment time and increased power. Conclusion: Using cylindrical diffusers, interstitial laserinduced thermotherapy without carbonization at the fiber tip can be as efficient as treatment with carbonization. Lasers