A Multiple-Source Delivery System for Interstitial Laser Photocoagulation

Abstract

Interstitial laser photocoagulation (ILP) is a minimally invasive technique for destroying solid, localised tumours thermally by delivering infrared laser energy directly into the targeted volume via percutaneously implanted optical fibres. Using current treatment parameters, each fibre delivers sufficient energy to destroy a volume of one to two cm³; larger lesions may be created by using multiple fibres excited simultaneously. An efficient delivery system has been constructed consisting of several fibres bundled through a single cannula and splayed out through a specially designed tip. This delivery system is simple to use and provides accurate fire placement. By linearly superposing single source solutions to the bioheat transfer equation, a mathematical model for coalescent thermal lesions has been developed. It has been determined that large, clinically useful thermal lesions can be created by implanting four sources at the corners of a square. It has been demonstrated, through 𝘦𝘹 𝘷𝘪𝘷𝘰 experimentation in bovine liver, that the model correctly predicts the dimensions of the thermal lesions.