Bio-Heat Transfer in Cancer Treatment: A Mathematical Framework for Hyperthermia-Assisted Radiotherapy Using Monte Carlo Simulation

Abstract

This study explores bio-heat transfer during radiotherapy combined with hyperthermia, with the goal of improving cancer treatment by maximizing tumor destruction while minimizing harm to surrounding healthy tissue. Understanding thermal dynamics during therapy allows clinicians to enhance treatment effectiveness, anticipate biological responses based on dose parameters, and reduce side effects. In this work, we focus on the synergistic use of hyperthermia and X-ray radiotherapy. During short recovery periods between hyperthermia pulses—when tissue responds to elevated temperatures (43 °C, 45 °C, 47 °C)—radiation is delivered. The central hypothesis is that heating tumor tissue increases its radiosensitivity, potentially shortening treatment time and improving outcomes. Evidence from current literature supports this synergy, showing that higher temperatures amplify cellular damage. To quantify this effect, we applied the Arrhenius damage model, which converts temperature and exposure duration into a single thermal damage parameter (Ω) representing irreversible tissue injury. Finally, we developed a mathematical framework to simulate this process, using Monte Carlo photon transport to generate spatial heat sources and solving Pennes’ bio-heat equation to model heat transfer across layered biological tissue.