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.

中文翻译：

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一项多机构研究：使用拟人模型对五个不同的MR引导的深部高温系统的加热方式进行比较。

摘要

介绍

在热疗界，人们一致认为放疗和/或化学疗法加热疗的临床结局（即将肿瘤温度升高至40-44°C）与所应用的热剂量有关。因此，治疗质量对于前瞻性多机构临床试验的成功至关重要。当前，在每个机构中，使用基本的圆柱体模型独立地执行涂药质量保证（QA）测量。使用磁共振测温（MRT）和解剖学代表性拟人化体模对加热质量进行多机构比较，为获得新颖的QA见解提供了独特的机会，以促进多机构试验评估。

目的

执行系统的质量检查程序，以比较五个机构中MR兼容的高温系统的性能。

方法和材料

产生了包括盆骨和脊骨在内的拟人化体模。临床相关功率为600瓦，持续约12分钟，以进行8次连续MR扫描。分析了3D加热分布，转向能力和脱靶加热的存在。

结果

评估后的设备显示出针对中心和偏心目标的可比加热曲线。在3D加热曲线中观察到的差异是由于精确的体模定位和涂药器特性发生变化的结果，因此，体模的定位遵循当前的ESHO-QA指南。

结论

拟人化体模用于在不同品牌的MR扫描仪中对MR引导的高温系统进行QA测量。显示了五个评估机构的可比加热曲线。在评估加热模式时，亚厘米级的位置差异会严重影响结果。应评估先进的体模和质量保证指南中精确定位的集成，以确保提供最佳质量的患者护理。