Review of Thermal and Physiological Properties of Human Breast Tissue

Abstract

Electromagnetic thermal therapies for cancer treatment, such as microwave hyperthermia, aim to heat up a targeted tumour site to temperatures within 40 and 44 °C. Computational simulations used to investigate such heating systems employ the Pennes’ bioheat equation to model the heat exchange within the tissue, which accounts for several tissue properties: density, specific heat capacity, thermal conductivity, metabolic heat generation rate, and blood perfusion rate. We present a review of these thermal and physiological properties relevant for hyperthermia treatments of breast including fibroglandular breast, fatty breast, and breast tumours. The data included in this review were obtained from both experimental measurement studies and estimated properties of human breast tissues. The latter were used in computational studies of breast thermal treatments. The measurement methods, where available, are discussed together with the estimations and approximations considered for values where measurements were unavailable. The review concludes that measurement data for the thermal and physiological properties of breast and tumour tissue are limited. Fibroglandular and fatty breast tissue properties are often approximated from those of generic muscle or fat tissue. Tumour tissue properties are mostly obtained from approximating equations or assumed to be the same as those of glandular tissue. We also present a set of reliable data, which can be used for more accurate modelling and simulation studies to better treat breast cancer using thermal therapies.

Rotationally Adjustable Hyperthermia Applicators: A Computational Comparative Study of Circular and Linear Array Applicators

“…The calculation was performed with MATLAB with a finite difference time domain (FDTD) method and a Dirichlet boundary condition, such that the initial temperature and the boundary of the breast were kept at a fixed temperature of 37 °C. The thermal properties of the phantom were taken from [ 10 ]. Time was changed into 300 time steps with increments of two seconds, which is the maximum time step ensuring the convergence, completing 10 min of temperature increase.…”

“…The steps of proper hyperthermia treatment planning (HTP) can be summarized as follows: After the patient is diagnosed with a malignant tumor, detailed imaging of the body part is obtained and the tissues are segmented [ 4 , 5 ]. Next, the accurate microwave dielectric and thermal properties of the tissues are assigned to each tissue type [ 6 , 7 , 8 , 9 , 10 ]. Then, the proper antenna excitations are applied for a controlled increase of the tumor temperature and hotspot prevention in the remaining healthy tissue, in other words the effective focusing of the specific absorption rate ( ) on the target.…”

Magnetic resonance imaging of blood perfusion rate based on Helmholtz decomposition of heat flux

“…Imaging the thermal properties (TPs) of human tissues, such as blood perfusion parameters and thermal conductivity, is helpful for tumor diagnosis and treatment. Images of TPs can assist in the diagnosis of breast tumors, because breast tumors and healthy breast tissues have different TPs (Duck 2013, Lozano et al 2020, Said Camilleri et al 2022. In particular, the blood perfusion rate is significantly different for cancerous and healthy breast tissues.…”

Investigation of Microwave Electromagnetic Fields in Open and Shielded Areas and Their Possible Effects on Biological Structure

“…Studies conducted at several medical, pharmaceutical, and technical universities concluded that the influence of mobile phones leads to eye strain, lack of sleep, migraines, restlessness, and irritability and may cause hearing impairment. Radiation from mobile phones and their effect has been found to have a greater effect on people under 20 years of age [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ].…”