Uto Megumi, Iramina Hiraku, Iwai Takahiro, Yoshimura Michio, Mizowaki Takashi
Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Pract Radiat Oncol. 2025 Jan-Feb;15(1):e40-e46. doi: 10.1016/j.prro.2024.07.013. Epub 2024 Sep 28.
Radiation therapy is the standard treatment for localized gastric mucosa-associated lymphoid tissue (MALT) lymphoma. The ETHOS system (Varian Medical System) has enabled us to perform cone beam computed tomography (CBCT)-guided online adaptive radiation therapy (oART). This study presents a retrospective dosimetric analysis for interfractional and intrafractional change and treatment time in oART for gastric MALT lymphoma. We included 3 male patients with gastric MALT lymphoma who underwent exhalation breath-hold fasting oART using the SpiroDynr'X system. Treatment details and plans (3 reference [REF] plans, 51 scheduled [SCH] plans, and adapted [ADP] plans) were retrospectively analyzed. Doses to the clinical target volume in planning CT (CTV_REF), CTV1, and CTV2 (representing the stomach in planning and preirradiation CBCT, respectively) and planning target volume (PTV) in the planning CBCT were estimated. D, D, D, and D for these volumes, along with organ-at-risk doses, were examined across the 3 plans. The PTV dose coverage of CTV2 on preirradiation CBCT was calculated. CBCT-guided oART was completed within the scheduled period, using the ADP plans instead of the SCH plans on each treatment day in all cases. The average treatment time was approximately 45 minutes. CTV1 and CTV2 exhibited intrafractional and interfractional variations, fluctuating above and below CTV_REF. Some ADP plans resulted in incomplete PTV coverage of CTV2, but the unincluded volume was <1% of CTV2. D, D, and D of CTV1, CTV2, and PTV were significantly improved in the ADP plans than in the SCH plans. Moreover, the D to the liver and kidneys was reduced in the ADP plans. CBCT-guided oART in patients with gastric MALT lymphoma demonstrated that ADP plans improved CTV1, CTV2, and PTV doses and reduced the mean bilateral kidney and liver doses, suggesting that it may offer enhanced treatment precision for gastric MALT lymphoma.
放射治疗是局限性胃黏膜相关淋巴组织（MALT）淋巴瘤的标准治疗方法。ETHOS系统（瓦里安医疗系统公司）使我们能够进行锥形束计算机断层扫描（CBCT）引导的在线自适应放射治疗（oART）。本研究对胃MALT淋巴瘤oART中分次间和分次内的变化以及治疗时间进行了回顾性剂量分析。我们纳入了3例胃MALT淋巴瘤男性患者，他们使用SpiroDynr'X系统进行呼气屏气禁食oART。对治疗细节和计划（3个参考[REF]计划、51个预定[SCH]计划和适应性[ADP]计划）进行了回顾性分析。估计了计划CT（CTV_REF）、CTV1和CTV2（分别代表计划和放疗前CBCT中的胃）的临床靶区体积以及计划CBCT中的计划靶区体积（PTV）的剂量。在这3个计划中检查了这些体积的D、D、D和D以及危及器官的剂量。计算了放疗前CBCT上CTV2的PTV剂量覆盖情况。在所有病例中，CBCT引导的oART均在预定时间内完成，每个治疗日使用ADP计划而非SCH计划。平均治疗时间约为45分钟。CTV1和CTV2表现出分次内和分次间的变化，在CTV_REF上下波动。一些ADP计划导致CTV2的PTV覆盖不完全，但未覆盖的体积<CTV2的1%。与SCH计划相比，ADP计划中CTV1、CTV2和PTV的D、D和D有显著改善。此外，ADP计划中肝脏和肾脏的D降低。胃MALT淋巴瘤患者的CBCT引导oART表明，ADP计划改善了CTV1、CTV2和PTV的剂量，并降低了双侧肾脏和肝脏的平均剂量，这表明它可能提高胃MALT淋巴瘤的治疗精度。
