Thermal Therapy, Part IV: Electromagnetic and Thermal Dosimetry

Abstract

ABSTRACT:In this article some of the important techniques in electromagnetic (EM) and thermal dosimetry are reviewed. Three major areas are discussed: modeling power deposition and estimation of EM energy absorbed by tissues exposed to EM radiation, electrical-thermal modeling for thermal therapy with various models of heat transfer in living tissues, and thermal dosimetry using invasive and noninvasive thermometry. Knowledge about the temperature distributions achieved can only be obtained by treatment planning of patient therapy. This process is called thermal therapy planning system (TTPS), which is a large and complex system for design, control, documentation, and evaluation of the treatment that also provides data for treatment optimization. Various imaging techniques for guidance and monitoring necessary for clinical treatments are also discussed. The review concludes by suggesting future avenues for investigations.

Multi–Frequency Analysis For Interstitial Microwave Hyperthermia Using Multi–Slot Coaxial Antenna

“…The second term relates to the phenomenon of heat conduction in the tissue, which is determined by the tissue thermal conductivity λ (W m −1 K −1 ). The third term describes the heat exchange between the tissue and blood and specifies the heat losses caused by tissue blood flow (perfusion) [18]. What is important, the subscript " b " refers to the blood, such in ω b which means the blood perfusion rate (s −1 ).…”

A numerical study on microwave coagulation therapy

“…Then the microwave energy provided by the antenna heats up the tumor to about 50°C to destroy cancer cells. Medical applications of microwaves and their numerical models have been actively studied and developed for many years, see [1][2][3][4][5][6] and the references therein. The antenna consists of a thin coaxial cable in a catheter.…”

“…All physical dimensions of the antenna are also given in Figure 1. In this study, we adopt the commercial software COMSOL [5] as a numerical model. We first solve the Maxwell equations and compute the electromagnetic specific absorption rate.…”

“…In the treatment, a thin microwave antenna is inserted into the cancerous tissue and the microwave energy heats up the tumor, killing the cancer cells by producing a coagulated region. Numerical models of microwave cancer therapy have been studied for many years with mature algorithms and software packages [1][2][3][4][5][6]. Despite this, the relationships between numerous parameters such as input power, frequency, temperature, and regions of impact are modeled with partial differential equations, which are not ideal or convenient for engineering design and clinical applications.…”

Extended Generalized Riccati Equation Mapping for Thermal Traveling-Wave Distribution in Biological Tissues through a Bio-Heat Transfer Model with Linear/Quadratic Temperature-Dependent Blood Perfusion

“…Spatially distributed heating occurs in skin exposed to penetrating, dissipative radiation such as microwave, ultrasound, and laser light [25][26][27]. These heating methods often involve an exponentially decaying power transmission accompanied by reflection at the interface of regions with different electrical properties.…”