Theoretical assessment of principal factors influencing laser interstitial thermotherapy outcomes on pancreas

The influence of some therapy-relevant parameters on Laser Induced Interstitial Thermotherapy (LITT) outcomes on pancreas is assessed. The aim is to execute a sensitivity analysis for an optimal treatment strategy on in vivo pancreas. A numerical model based on Bioheat Equation has been implemented to assess the influence of laser settings (power P and energy E), applicator radius (rf) and optical properties (effective attenuation coefficient, μeff) on temperature (T) distribution. Effects on pancreas undergoing LITT have been evaluated with a twofold approach: 1) T rise and maximum T (Tmax) in tissue; 2) injured volumes (vaporized and coagulated ones). We consider parameters range in typical LITT values (P from 1.5 W to 6 W, E from 500 J to 1500 J, rf from 150 μm to 600 μm) and optical values reported in literature. Our analysis shows that, among others, P and μeff are the principal influencing factors of thermal effects on pancreas undergoing LITT: P should be carefully chosen by operator to obtain the desired injured volumes, while the accurate measurement of tissue optical properties is crucial to carry out a safe and controlled thermal therapy on pancreas.