Hu Yue-Houng, Harper Riley H, Deiter Noelle C, Evans Jaden D, Mahajan Anita, Kruse Jon J, Mundy Daniel W
Department of Radiation Oncology, Division of Medical Physics, Mayo Clinic, Rochester, MN, USA.
College of Science and Engineering, University of Minnesota, Minneapolis, MN, USA.
Int J Part Ther. 2022 Jun 28;9(2):49-58. doi: 10.14338/IJPT-21-00043.1. eCollection 2022 Fall.
Finite proton range affords improved dose conformality of radiation therapy when patient regions-of-interest geometries are well characterized. Substantial changes in patient anatomy necessitate re-planning (RP) to maintain effective, safe treatment. Regularly planned verification scanning (VS) is performed to ensure consistent treatment quality. Substantial resources, however, are required to conduct an effective proton plan verification program, which includes but is not limited to, additional computed tomography (CT) scanner time and dedicated personnel: radiation therapists, medical physicists, physicians, and medical dosimetrists.
Verification scans (VSs) and re-plans (RPs) of 711 patients treated with proton therapy between June 2015 and June 2018 were studied. All treatment RP was performed with the intent to maintain original plan integrity and coverage. The treatments were classified by anatomic site: brain, craniospinal, bone, spine, head and neck (H&N), lung or chest, breast, prostate, rectum, anus, pelvis, esophagus, liver, abdomen, and extremity. Within each group, the dates of initial simulation scan, number of VSs, number of fractions completed at the time of VS, and the frequency of RP were collected. Data were analyzed in terms of rate of RP and individual likelihood of RP.
A total of 2196 VSs and 201 RPs were performed across all treatment sites. H&N and lung or chest disease sites represented the largest proportion of plan modifications in terms of rate of re-plan (RoR: 54% and 58%, respectively) and individual likelihood of RP on a per patient basis (likelihood of RP [RP%]: 46% and 39%, respectively). These sites required RP beyond 4 weeks of treatment, suggesting continued benefit for frequent, periodic VS. Disease sites in the lower pelvis demonstrated a low yield for RP per VS (0.01-0.02), suggesting that decreasing VS frequency, particularly late in treatment, may be reasonable.
A large degree of variation in RoR and individual RP% was observed between anatomic treatment sites. The present retrospective analysis provides data to help develop anatomic site-based VS protocols.
当患者感兴趣区域的几何形状得到充分表征时，有限的质子射程可提高放射治疗的剂量适形性。患者解剖结构的显著变化需要重新规划（RP）以维持有效、安全的治疗。定期进行计划验证扫描（VS）以确保治疗质量的一致性。然而，开展有效的质子计划验证项目需要大量资源，这包括但不限于额外的计算机断层扫描（CT）扫描仪时间和专业人员：放射治疗师、医学物理学家、医生和医学剂量师。
对2015年6月至2018年6月期间接受质子治疗的711例患者的验证扫描（VS）和重新规划（RP）进行了研究。所有治疗性RP均旨在维持原计划的完整性和覆盖范围。治疗按解剖部位分类：脑、颅脊髓、骨、脊柱、头颈部（H&N）、肺或胸部、乳腺、前列腺、直肠、肛门、骨盆、食管、肝脏、腹部和四肢。在每组中，收集初始模拟扫描日期、VS次数、VS时完成的分次次数以及RP频率。对RP率和个体RP可能性的数据进行了分析。
所有治疗部位共进行了2196次VS和201次RP。就重新规划率（RoR：分别为54%和58%）和每位患者的个体RP可能性（RP可能性[RP%]：分别为46%和39%）而言，H&N以及肺或胸部疾病部位的计划修改占比最大。这些部位在治疗4周后仍需要RP，表明频繁、定期的VS持续有益。下骨盆的疾病部位每次VS的RP产出较低（0.01 - 0.02），这表明降低VS频率，尤其是在治疗后期，可能是合理的。
在解剖治疗部位之间观察到RoR和个体RP%存在很大差异。本回顾性分析提供的数据有助于制定基于解剖部位的VS方案。
