A multi-institution study: comparison of the heating patterns of five different MR-guided deep hyperthermia systems using an anthropomorphic phantom

Abstract

Introduction: Within the hyperthermia community, consensus exists that clinical outcome of the treatment radiotherapy and/or chemotherapy plus hyperthermia (i.e. elevating tumor temperature to 40 À 44 C) is related to the applied thermal dose; hence, treatment quality is crucial for the success of prospective multi-institution clinical trials. Currently, applicator quality assurance (QA) measurements are implemented independently at each institution using basic cylindrical phantoms. A multi-institution comparison of heating quality using magnetic resonance thermometry (MRT) and anatomical representative anthropomorphic phantoms provides a unique opportunity to obtain novel QA insights to facilitate multi-institution trial evaluation. Objective: Perform a systematic QA procedure to compare the performance of MR-compatible hyperthermia systems in five institutions. Methods and materials: Anthropomorphic phantoms, including pelvic and spinal bones, were produced. Clinically relevant power of 600 watts was applied for $12 min to allow for 8 sequential MRscans. The 3D-heating distribution, steering capabilities, and presence of off-target heating were analyzed. Results: The evaluated devices show comparable heating profiles for centric and eccentric targets. The differences observed in the 3D-heating profiles are the result of variations in the exact phantom positioning and applicator characteristics, whereby positioning of the phantom followed current ESHO-QA guidelines. Conclusion: Anthropomorphic phantoms were used to perform QA-measurements of MR-guided hyperthermia systems operating in MR-scanners of different brands. Comparable heating profiles are shown for the five evaluated institutions. Subcentimeter differences in position substantially affected the results when evaluating the heating patterns. Integration of advanced phantoms and precise positioning in QA-guidelines should be evaluated to guarantee the best quality patient care.

The Effects of Localized Heat on the Hallmarks of Cancer

“…Of course, this implies that precise temperature doses must be applied to the tumor region, which remains a challenge for thermal techniques currently in clinical use due to the inaccessibility of deep tumors, heterogeneous temperature distributions associated with hyperthermia treatment, and the need for more advanced thermal modelling systems to establish greater control over dosimetry. [253][254][255]…”

Contactless Thermometry by MRI and MRS: Advanced Methods for Thermotherapy and Biomaterials

“…To render tests of noninvasive thermometry in hyperthermia conclusive and ensure its widespread use in the clinic, it is vital to subject this relatively new method to multi-institutional evaluation. One such quality assurance study has been presented for deep-pelvic MW hyperthermia systems operating in multi-vendor MR-systems, using a new anthropomorphic phantom (Curto et al, 2019); see also Table S1. These authors have systematically compared hyperthermia-induced temperature variations to values obtained by invasive temperature probe measurements using high-resistance thermistors, the current gold standard.…”

Visualization of thermal washout due to spatiotemporally heterogenous perfusion in the application of a model-based control algorithm for MR-HIFU mediated hyperthermia

“…In the future, the use of magnetic resonance imaging (MRI)-based thermometry during EMW-hyperthermia may further improve clinical outcomes by providing the operator with 3D temperature information at higher spatial resolutions [39,40]. The systematic validation of a device for EMW-mediated RHT under MRI guidance is currently ongoing [34,35,41].…”