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 − 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 MR-scans. 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.

Keywords:

• Quality assurance (QA)
• magnetic resonance (MR)-guided hyperthermia
• magnetic resonance thermometry (MRT)
• anthropomorphic phantom
• heating patterns

Acknowledgements

This work was performed within the framework of ‘European Cooperation in Science and Technology’: COST Action EMF-MED.

Disclosure statement

Dr. Curto reports grants from Pyrexar Medical Corp. and COST during the conduct of the study. Mr. Mulder reports grants from the Dutch Cancer Society during the conduct of the study. Mr. Lamprecht reports grants from Dr. Sennewald Medizintechnik GmbH during the conduct of the study, and grants from Elekta and Siemens outside the submitted work. Dr. Peller reports other from Dr. Sennewald Medizintechnik GmbH outside the submitted work. Dr. Lindner reports grants from Dr. Sennewald Medizintechnik GmbH during the conduct of the study. Dr. Fietkau reports personal fees from Dr. Sennewald Medizintechnik GmbH during the conduct of the study; grants and personal fees from Merck Serono, Astra Zenica, and MSD; and personal fees from Novocure, Brainlab, Fresenius Kabi, and Bristol Myers Squibb outside the submitted work. Dr. Zips reports financial support from Dr. Sennewald for educational events during the conduct of the study, and grants from Elekta and Siemens outside the submitted work. Dr. Paulides reports grants from the Dutch Cancer Society during the conduct of the study. Dr. van Rhoon reports grants from the Dutch Cancer Society (KWF-DDHK 2013-6072) and Pyrexar Medical Corp. during the conduct of the study, and other from Sensius BV outside the submitted work. All authors declare no competing interests and full responsibility for the content of the article.

Additional information

Funding

This work was financially supported by unrestricted grants from the Dutch Cancer Society KWF-DDHK 2013-6072, Pyrexar Medical Corp., and Dr. Sennewald Medizintechnik GmbH.