Human body models for validation studies of deep hyperthermia
Department of Information Engineering,
Electronics and Telecommunications,
Sapienza University of Rome, Via
Eudossiana, 18, Rome, 00184, Italy
MED-LOGIX srl, Via Adriano Olivetti
24, Rome, 00131, Italy
M. Cavagnaro, Department of
Information Engineering, Electronics and
University of Rome, Via Eudossiana, 18,
Rome, 00184, Italy.
Hyperthermia is a therapeutic technique used to enhance the efficacy of radiotherapy
and chemotherapy in the treatment of oncological pathologies, by way of a temperature
increase of 41–438C in the target region. To validate hyperthermia devices, as well as
the numerical codes used to simulate hyperthermia treatments, simple phantoms are
used. This article considers the influence of phantoms’ geometry, dimensions, and
considered organs, on the electromagnetic power absorption. Aim of the study was to
evaluate the representativeness of such simple phantoms in terms of the power
absorbed by the organs target of deep hyperthermia treatments (i.e., uterus and
bladder). In particular, attention was posed on the influence of the visceral fat on the
distribution of the absorbed power among the different organs. Results show that
geometry and dimension does not influence the distribution of the absorbed power
among the different tissues/organs (the maximum difference is 4% in the bladder).
However, neglecting the presence of visceral fat greatly changes the electromagnetic
power absorbed by the target organs, leading to a 23% increase of the percentage
power absorbed in the uterus with respect to the complete model. This percent value
corresponded to an increase in the volume-averaged SAR of 140%.
hyperthermia treatments, numerical simulations, phantoms
In recent years, the use of hyperthermia as an additive
treatment to radiotherapy and chemotherapy in nonsurgical
oncological pathologies is growing.
The goal of hyper-
thermia is to increase the temperature in the target region
to 418C–438C for about 60 min.
mechanisms are induced in the cells at these temperatures,
some related to a direct cytotoxic effect of heat, others to
the improvement of radio and/or chemo outcomes. In par-
ticular, the center of the tumor cell is often poorly vascular-
ized and, as a consequence, it is hypoxic and with an
acidic pH. These features lead to a greater vulnerability to
heat of tumor cells with respect to healthy ones.
over, heating inhibits cell repair mechanisms of the damage
induced by radiotherapy, and makes cell membrane more
The last described mechanism proves the
strong link between hyperthermia and chemotherapy: in
the periphery of the tumor, where there is an increased
angiogenesis, hyperthermia activates thermoregulation, i.e.,
promotes an increasing blood flow, thus inducing a greater
transport of the chemo agent to the tumor site. Here, the
heat-increased permeability of the cell’s membrane allows
greater drugs absorption.
The temperature increase of hyperthermia treatments can
be obtained in several ways. E.g., whole body heating was
achieved by using hot air, hot water suits, or infrared radia-
tion, while partial body heating was realized utilizing ultra-
sound, heated blood, fluid perfusion, radio frequency (RF) or
microwave (MW) electromagnetic fields.
netic fields have been applied by using external, intra-
cavitary and interstitial techniques. In case of external sour-
ces, i.e., noninvasive treatments, radiative systems are used,
operating at 70–100 MHz in case of deep-seated tumors
(e.g., cervix, bladder, rectum, etc.) or at 434 MHz and 915
MHz in case of superficial tumors (e.g., head and neck, etc.).
Additionally, capacitive systems are used, operating in the
8–30 MHz frequency band.
Int J RF Microw Comput Aided Eng. 2018;28:e21207.
2017 Wiley Periodicals, Inc.
Received: 17 July 2017
Revised: 20 November 2017
Accepted: 20 November 2017