Because proton beam therapy (PBT) can lower the dose of radiation to the heart, lungs, and breast, it is an established radiation modality for patients with Hodgkin lymphoma (HL). Pencil beam scanning (PBS) PBT facilitates the treatment of more extensive targets. This may be especially of value for lymphoma patients who require RT to both mediastinal and axillary targets, defined here as extended target RT (ETRT), given the target distribution and need to minimize the lung, heart, and breast dose. Using the Proton Collaborative Group registry, we identified patients with HL treated with PBT to both their mediastinum and axilla, for which DICOM-RT was available. All patients were treated with PBS. To evaluate the dosimetric impact of PBS, we compared delivered PBS plans with VMAT butterfly photon plans optimized to have the same target volume coverage, when feasible. Between 2016 and 2021, twelve patients (median 26 years) received PBS ETRT (median 30.6 Gy (RBE)). Despite the large superior/inferior (SI, median 22.2 cm) and left/right (LR, median 22.8 cm) extent of the ETRT targets, all patients were treated with one isocenter except for two patients (both with SI and LR > 30 cm). Most commonly, anterior beams, with or without posterior beams, were used. Compared to photons, PBS had greater target coverage, better conformity, and lower dose heterogeneity while achieving lower doses to the lungs and heart, but not to the breast. No acute grade 3+ toxicities were reported, including pneumonitis. Proton ETRT in this small cohort was safely delivered with PBS and was associated with an improved sparing of the heart and lungs compared to VMAT.
由于质子束治疗（PBT）能够降低对心脏、肺部和乳房的辐射剂量，它已成为霍奇金淋巴瘤（HL）患者的一种成熟放射治疗方式。笔形束扫描（PBS）质子束治疗有助于治疗更广泛的靶区。这对于需要同时对纵隔和腋窝靶区进行放射治疗（此处定义为扩展靶区放射治疗，ETRT）的淋巴瘤患者尤其有价值，考虑到靶区分布以及需要最小化对肺、心脏和乳房的辐射剂量。通过利用质子协作组注册数据库，我们识别出接受质子束治疗同时覆盖纵隔和腋窝的霍奇金淋巴瘤患者，这些患者均有可用的DICOM-RT数据。所有患者均采用笔形束扫描技术进行治疗。为评估笔形束扫描的剂量学影响，我们在可行的情况下，将已实施的笔形束扫描计划与优化至具有相同靶区覆盖范围的VMAT蝴蝶光子计划进行了比较。在2016年至2021年间，12名患者（中位年龄26岁）接受了笔形束扫描扩展靶区放射治疗（中位剂量30.6 Gy（RBE））。尽管扩展靶区靶区在上下方向（中位22.2厘米）和左右方向（中位22.8厘米）上范围较大，除两名患者（上下和左右方向均大于30厘米）外，所有患者均使用一个等中心点进行治疗。最常使用的是前向束流，有时结合后向束流。与光子治疗相比，笔形束扫描在实现更低肺部和心脏剂量（但对乳房剂量无此优势）的同时，具有更好的靶区覆盖率、更优的适形性和更低的剂量异质性。未报告急性3级及以上毒性反应，包括肺炎。在这一小规模队列中，笔形束扫描质子扩展靶区放射治疗安全实施，并且与VMAT相比，显示出对心脏和肺部更好的保护效果。
肿瘤(癌症)患者之家