Finite element analysis for simplified thermal dose planning in interstitial laser thermotherapy
Summary, in English
The objective was to investigate if diffusing laser fibres can be modelled as conductive heat sources without miscalculating coagulated volumes, and if finite element analysis, disregarding light transport, may be used for three dimensional (3D) treatment planning in interstitial laser thermotherapy (ILT). Temperature distributions and coagulated volumes with a diffusing laser fibre, as compared to a conductive heat source, were numerically calculated at equal output power and with optical tissue properties corresponding to coagulated human liver. Blood flow was absent in the model. The maximum temperature with the diffusing fibre was limited to 100 °C and 5, 10, 20 and 30 minutes heating time was studied. A 3D finite element model was used to calculate temperatures during heating with four cylindrical heat sources (no light emission) and results were compared to measured temperatures during laser irradiation in gel with known optical properties. Coagulated volumes with a single diffusing or conductive applicator ranged from 3.5 to 12.6 cm3 and differed less than 1% at all studied irradiation times. Calculated and measured temperatures with four applicators agreed excellently. The present study should be relevant to ILT of the human liver, when inflow is occluded.
Proceedings of SPIE - The International Society for Optical Engineering
Proceedings of the 1998 Thermal Therapy, Laser Welding, and Tissue Interaction
1998-09-09 - 1998-09-11
- ISSN: 0277-786X