Purpose: We studied the differences between planning and treatment position, their impact on the accuracy of hyperthermia treatment planning (HTP) predictions, and the relevance of including true treatment anatomy and position in HTP based on magnetic resonance (MR) images. Materials and methods: All volunteers were scanned with an MR-compatible hyperthermia device, including a filled waterbolus, to replicate the treatment setup. In the planning setup, the volunteers were scanned without the device to reproduce the imaging in the current HTP. First, we used rigid registration to investigate the patient position displacements between the planning and treatment setup. Second, we performed HTP for the planning anatomy at both positions and the treatment mimicking anatomy to study the effects of positioning and anatomy on the quality of the simulated hyperthermia treatment. Treatment quality was evaluated using SAR-based parameters. Results: We found an average displacement of 2 cm between planning and treatment positions. These displacements caused average absolute differences of ∼12% for TC25 and 10.4%–15.9% in THQ. Furthermore, we found that including the accurate treatment position and anatomy in treatment planning led to an improvement of 2% in TC25 and 4.6%–10.6% in THQ. Conclusions: This study showed that precise patient position and anatomy are relevant since these affect the accuracy of HTP predictions. The major part of improved accuracy is related to implementing the correct position of the patient in the applicator. Hence, our study shows a clear incentive to accurately match the patient position in HTP with the actual treatment.
|Journal||International Journal of Hyperthermia|
|Publication status||Published - 2023|
Bibliographical noteFunding Information:
This research has been made possible by the Dutch Cancer Society and the Netherlands Organization for Scientific Research (NWO) as a part of their joint Partnership Programme: ‘Technology for Oncology’ grant number: 15195 and the Dutch Cancer Society grant KWF-DDHK 2013-6072. Additionally, our research was supported by COST Action MyWave CA17115 ‘European network for advancing Electromagnetic hyperthermic medical technologies’. The authors thank Theresa Feddersen, Ioannis Androulakis and Gennaro Bellizzi for their assistance during the volunteer experiments. Furthermore, the authors thank Pelle ter Haar for his help in the process of tissue delineation, Piotr A. Wielopolski for his support in the development of the MR protocol, and Erik van Werkhoven for his advice in the statistical analysis.
© 2022 The Author(s). Published with license by Taylor & Francis Group, LLC.