Kielbasa Jerrold E, Kimble Logan, Rineer Justin, Swanick Cameron W, Kelly Patrick, Shah Amish P
Department of Radiation Oncology, Orlando Health Cancer Institute, United States.
Phys Imaging Radiat Oncol. 2025 Jun 11;35:100791. doi: 10.1016/j.phro.2025.100791. eCollection 2025 Jul.
This work aims to develop a magnetic resonance (MR)-only treatment planning protocol for integration into magnetic resonance simulation (MR-SIM), on-table treatment planning, and immediate treatment workflow for rapid palliation of painful spine metastases.
Thirty-five treatment plans from healthy volunteers were generated on MR-SIM scans using a protocol including: (1) a library of 4 planning target volume (PTV) structures based on vertebral level, (2) default beam templates covering the PTVs while avoiding organs at risk (OAR), (3) bulk density assignments for dose calculations, and (4) a single set of dose optimization parameters. We transferred each plan to the patient's prior computed tomography simulation (CT-SIM) images and compared dosimetric parameters. A time study was performed on the MR-SIM, on-table planning, and immediate treatment workflow for all 35 cases using healthy volunteers.
All bulk density MR-SIM plans resulted in acceptable dose distributions, with 100 % deemed appropriate for treatment by two physicians. The maximum point dose was within 3.2 %, and the minimum dose to 90 % of the target volume was within 2.8 % of the prescription dose. The time study demonstrated that the proposed workflow could be completed in a mean time of 23.6 min for the 3 Gy (10 fractions) plan and 25.4 min for the 8 Gy (single fraction) plan, from patient placement to treatment completion.
These results demonstrate that safe, fast palliation of spine metastases can be achieved in under 30 min using MR-SIM, bulk density on-table planning, and immediate treatment delivery.
本研究旨在开发一种仅基于磁共振（MR）的治疗计划方案，以整合到磁共振模拟（MR-SIM）、术中治疗计划以及用于快速缓解脊柱转移瘤疼痛的即时治疗工作流程中。
使用包含以下内容的方案，在MR-SIM扫描上为35名健康志愿者生成治疗计划：（1）基于椎体水平的4种计划靶区（PTV）结构库；（2）覆盖PTV同时避开危及器官（OAR）的默认射束模板；（3）用于剂量计算的体密度赋值；（4）单一的剂量优化参数集。我们将每个计划转移到患者先前的计算机断层扫描模拟（CT-SIM）图像上，并比较剂量学参数。使用健康志愿者对所有35例病例的MR-SIM、术中计划和即时治疗工作流程进行了时间研究。
所有体密度MR-SIM计划均产生了可接受的剂量分布，两名医生均认为100%适合治疗。最大点剂量在3.2%以内，靶区体积90%的最小剂量在处方剂量的2.8%以内。时间研究表明，从患者安置到治疗完成，对于3 Gy（10次分割）计划，所提议的工作流程平均可在23.6分钟内完成，对于8 Gy（单次分割）计划，平均可在25.4分钟内完成。
这些结果表明，使用MR-SIM、体密度术中计划和即时治疗交付，可在30分钟内实现脊柱转移瘤的安全、快速姑息治疗。
