Quality assurance (QA) guidelines are essential to provide uniform execution of clinical trials with uniform quality hyperthermia treatments. This document outlines the requirements for appropriate QA of all current superficial heating equipment including electromagnetic (radiative and capacitive), ultrasound, and infrared heating techniques. Detailed instructions are provided how to characterize and document the performance of these hyperthermia applicators in order to apply reproducible hyperthermia treatments of uniform high quality. Earlier documents used specific absorption rate (SAR) to define and characterize applicator performance. In these QA guidelines, temperature rise is the leading parameter for characterization of applicator performance. The intention of this approach is that characterization can be achieved with affordable equipment and easy-to-implement procedures. These characteristics are essential to establish for each individual applicator the specific maximum size and depth of tumors that can be heated adequately. The guidelines in this document are supplemented with a second set of guidelines focusing on the clinical application. Both sets of guidelines were developed by the European Society for Hyperthermic Oncology (ESHO) Technical Committee with participation of senior Society of Thermal Medicine (STM) members and members of the Atzelsberg Circle. Um eine einheitliche Durchführung klinischer Studien in der Hyperthermie zu gewährleisten, sind Leitlinien zur Qualitätssicherung (QA) unerlässlich. Dieses Dokument enthält die Anforderungen zur QA für alle aktuellen Therapiegeräte zur lokalen Hyperthermie, inklusive elektromagnetischer Systeme (radiativ und kapazitiv), Ultraschall- und Infrarottechnik. In detaillierten Anleitungen wird erklärt, wie die Leistungscharakteristik der Hyperthermieapplikatoren zu beschreiben und zu dokumentieren ist, um reproduzierbare, einheitliche und qualitativ hochwertige Hyperthermiebehandlungen zu gewährleisten. Im Gegensatz zu früheren Leitlinien wird anstelle der spezifischen Absorptionsrate (SAR) jetzt der Temperaturanstieg als maßgeblicher Parameter für die Beschreibung der Leistungscharakteristik von Hyperthermieapplikatoren verwendet. Grund für diesen Ansatz ist eine möglichst einfache und kostengünstige Leistungsbeschreibung. Diese ist notwendig, um für jeden einzelnen Applikator die maximale Tumorgröße und -tiefe zu bestimmen, die adäquat überwärmt werden kann. Dieses Dokument wird durch die Leitlinie zur klinischen Durchführung der lokalen Hyperthermie vervollständigt. Beide Teile der Leitlinie wurden vom Technischen Komitee der European Society for Hyperthermic Oncology (ESHO) in Zusammenarbeit mit leitenden Mitgliedern der Society of Thermal Medicine (STM) und Mitgliedern des Atzelsberger Kreises erarbeitet.

Microwave ablation (MWA) is a minimally invasive thermal therapy modality increasingly employed for the treatment of tumors and benign disease. For successful treatment, complete thermal coverage of the tumor and margin of surrounding healthy tissue must be achieved. Currently available interstitial antennas for MWA have cylindrically symmetric radiation patterns. Thus, when treating targets in proximity to critical structures, caution must be taken to prevent unintended thermal damage. A novel coaxial antenna design for MWA with an asymmetrical cylindrical heating pattern is presented in this paper. This radiation pattern is achieved by employing a hemicylindrical reflector positioned at a critical distance from a conventional coaxial monopole antenna. Finite-element method simulations were employed to optimize the geometric dimensions of the antenna with the objective of minimizing the antenna reflection coefficient at the 2.45-GHz operating frequency, and maximizing volume of the ablation zone. Prototype antennas were fabricated and experimentally evaluated. Simulations indicated an optimal S ₁₁ of -32 dB at 2.45 GHz in close agreement with experimental measurements of -29 dB. Ex vivo experiments were performed to validate simulations and observe effects to the antennas' heating pattern with the varying input power and geometry of the reflector. Ablation zones up to 20 mm radially were observed in the forward direction, with minimal heating (less than 4 mm) behind the reflector.

Measurement of specific loss power (SLP) of magnetic nanoparticles is crucial to assert the heating potential in magnetic hyperthermia. There has been a significant improvement in characterizing magnetic nanoparticles’ heat-triggered functions by many research groups. However, optimal experimental conditions along with notable determination methods of the SLP in magnetic hyperthermia have not been widely proposed until now. Despite the remarkable progress in this field, the evaluation process of SLP suffers from uncertainties and errors imposed not only by experimental parameters (depending on the particles, the conditions and the measurement) but by the estimation methodology, as well. In this work, we propose a step by step standardization protocol, starting from definition and recording of potential uncertainty and error sources, present during a typical magnetic hyperthermia experimental protocol. The error of each specific parameter is estimated and translated to ultimate heating efficiency evaluation. According to our analysis, magnetic hyperthermia experiment and its corresponding estimation, under non-adiabatic conditions, may lead to a propagated uncertainty up to 14% on the SLP value. Meanwhile, different heating evaluation methods were assessed under a wide range of experimental conditions, with the ‘modified law of cooling’ proving to be the most accurate one—limiting the SLP uncertainty to values under 5%—compared to the ‘initial slope’ and ‘Box–Lucas’ methods, which show a remarkable uncertainty of over 15%. All parameters involved in the heating efficiency evaluation and their associated uncertainties analysis presented in this work, are included in a standardisation protocol, a handy guideline for determining accurate, reliable and reproducible SLP values, thus adequately evaluating its impact in potential bioapplications.

Single element loop, dipole and conventional square patch antennas have been used as hyperthermia applicators in the treatment of cancerous human cells at superficial depths inside the body. A smaller novel patch antenna in very close proximity to a phantom tissue model produces an enhanced specific absorption rate pattern without significant frequency detuning or impedance mismatch. The new patch increases its coupling aperture by supporting a combination of resonances that are also typical for loop, dipole and square patch antennas. For computation efficiency and clarity in the synthesized hyperthermia treatment conditions, simplified planar tri-layered tissue models interfaced with a water-bolus are used to study the permittivity loading on the antennas and the resultant specific absorption rates.

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.