Zhong Xinran, Rahman Mahbubur, Simmons Ambrosia, Li Xingzhe, Kozak Malgorzata, Desai Neil, Timmerman Robert, Godley Andrew, Cai Bin, Parsons David, Kumar Kiran A, Lin Mu-Han
Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, Texas.
Adv Radiat Oncol. 2024 Dec 2;10(2):101692. doi: 10.1016/j.adro.2024.101692. eCollection 2025 Feb.
Daily online adaptive radiation therapy (oART) opens the opportunity to treat gastric mucosa-associated lymphoid tissue (MALT) lymphoma with a reduced margin. This study reports our early experience of cone beam computed tomography (CBCT)-based daily oART treating gastric MALT lymphoma with breath-hold and reduced margins.
Ten patients were treated on a CBCT-based oART system. Organs at risk (OARs) and the clinical target volume (CTV) were adjusted based on the daily CBCT. Planning target volume (PTV) was derived from the CTV with a 0.5 to 0.7 cm margin with breath-hold. Multiple beam arrangements were compared during the preplanning phase to ensure minimal monitor unit (MU) for patient comfort and breath-hold reproducibility. For 108 fractions from the 10 patients, the PTV, CTV coverage, and Paddick conformity index (CI) were compared between the adapted and scheduled plans. The MU, Paddick CI, and gradient index were compared using relative percentage differences between the adapted plans and preplans. The OAR doses from 106 fractions across 9 patients were reported for the preplans, adapted plans, and scheduled plans. The time statistics for each step of the clinical workflow were recorded and reported for 93 treatment fractions from 9 patients.
The PTV volume varied from -37.1% to 90.5% (11.7% ± 18.5%) throughout treatments across all patients. The adapted plan was chosen as the treatment plan for each fraction because of superior PTV and CTV coverage while maintaining a similar OAR dose. The PTV and CTV coverage for the adapted and scheduled plans was V = 95.0% ± 0.3% versus 64.1 ± 19.6% and V = 99.9 ± 0.1% versus 74.0% ± 22.2%, respectively. The adapted plans' MU, Paddick CI, and gradient index were, on average, 4.1%, 0.4%, and -4.2% of the preplan values, respectively. The console's adaptive workflow and physician time were 25 ± 7 and 19 ± 6 minutes, respectively.
A CBCT-based oART system with the proposed workflow is feasible for treating patients with gastric MALT lymphoma using a reduced PTV margin while maintaining excellent target coverage within a reasonable time, resulting in consistent adapted plan quality. This approach can be expanded to a larger cohort of gastrointestinal patients.
每日在线自适应放射治疗（oART）为以缩小边界治疗胃黏膜相关淋巴组织（MALT）淋巴瘤提供了机会。本研究报告了我们基于锥形束计算机断层扫描（CBCT）的每日oART在屏气和缩小边界情况下治疗胃MALT淋巴瘤的早期经验。
10例患者在基于CBCT的oART系统上接受治疗。根据每日CBCT调整危及器官（OARs）和临床靶区（CTV）。计划靶区（PTV）由CTV得出，屏气时边界为0.5至0.7厘米。在治疗前计划阶段比较多种射束排列，以确保患者舒适度和屏气重复性所需的监测单位（MU）最小。对于10例患者的108个分次，比较了适应性计划和预定计划之间的PTV、CTV覆盖情况以及帕迪克适形指数（CI）。使用适应性计划与预计划之间的相对百分比差异比较MU、帕迪克CI和梯度指数。报告了9例患者106个分次的预计划、适应性计划和预定计划的OAR剂量。记录并报告了9例患者93个治疗分次临床工作流程各步骤的时间统计数据。
所有患者在整个治疗过程中PTV体积变化范围为-37.1%至90.5%（11.7%±18.5%）。由于PTV和CTV覆盖情况更佳且OAR剂量相似，适应性计划被选为每个分次的治疗计划。适应性计划和预定计划的PTV和CTV覆盖情况分别为V = 95.0%±0.3%对64.1±19.6%以及V = 99.9±0.1%对74.0%±22.2%。适应性计划的MU、帕迪克CI和梯度指数平均分别为预计划值 的4.1%（0.4%和-4.2%。控制台的自适应工作流程时间和医生时间分别为25±7分钟和19±6分钟。
基于CBCT的oART系统以及所提出的工作流程对于治疗胃MALT淋巴瘤患者是可行的，可使用缩小的PTV边界，同时在合理时间内保持出色的靶区覆盖，从而使适应性计划质量保持一致。这种方法可扩展应用于更多的胃肠道疾病患者群体。
