Department of Radiation Oncology, Istituto del Radio O. Alberti, University of Brescia and Spedali Civili Hospital, Piazzale Spedali Civili 1, 25121, Brescia, Italy.
Department of Radiation Oncology, Ospedale Sacro Cuore Don Calabria, Negrar, Italy.
Radiol Med. 2024 Mar;129(3):497-506. doi: 10.1007/s11547-024-01788-w. Epub 2024 Feb 12.
Stereotactic radiotherapy (SRT) and Proton therapy (PT) are both options in the management of liver lesions. Limited clinical-dosimetric comparison are available. Moreover, dose-constraint routinely used in liver PT and SRT considers only the liver spared, while optimization strategies to limit the liver damaged are poorly reported.
Primary endpoint was to assess and compare liver sparing of four contemporary RT techniques. Secondary endpoints were freedom from local recurrence (FFLR), overall survival (OS), acute and late toxicity. We hypothesize that Focal Liver Reaction (FLR) is determined by a similar biologic dose. FLR was delineated on follow-up MRI. Mean C.I. was computed for all the schedules used. A so-called Fall-off Volume (FOV) was defined as the area of healthy liver (liver-PTV) receiving more than the isotoxic dose. Fall-off Volume Ratio (FOVR) was defined as ratio between FOV and PTV.
213 lesions were identified. Mean best fitting isodose (isotoxic doses) for FLR were 18Gy, 21.5 Gy and 28.5 Gy for 3, 5 and 15 fractions. Among photons, an advantage in terms of healthy liver sparing was found for Vmat FFF with 5mm jaws (p = 0.013) and Cyberknife (p = 0.03). FOV and FOVR resulted lower for PT (p < 0.001). Three years FFLR resulted 83%. Classic Radiation induced liver disease (RILD, any grade) affected 2 patients.
Cyberknife and V-MAT FFF with 5mm jaws spare more liver than V-MAT FF with 10 mm jaws. PT spare more liver compared to photons. FOV and FOVR allows a quantitative analysis of healthy tissue sparing performance showing also the quality of plan in terms of dose fall-off.
立体定向放射治疗（SRT）和质子治疗（PT）都是肝脏病变治疗的选择。目前可用的临床剂量比较有限。此外，肝脏 PT 和 SRT 中常规使用的剂量限制仅考虑到肝脏的受照体积，而限制肝脏损伤的优化策略则报道较少。
主要终点是评估和比较四种现代放射治疗技术的肝脏保护作用。次要终点是无局部复发（FFLR）、总生存率（OS）、急性和迟发性毒性。我们假设焦点肝脏反应（FLR）由相似的生物剂量决定。FLR 在随访 MRI 上勾画。计算所有使用方案的平均 C.I.。将所谓的“衰减体积（FOV）”定义为接受超等剂量的健康肝脏（肝-PTV）的区域。衰减体积比（FOVR）定义为 FOV 与 PTV 的比值。
共确定了 213 个病灶。FLR 的最佳拟合等剂量（等剂量）分别为 3、5 和 15 分次的 18Gy、21.5Gy 和 28.5Gy。在光子中，Vmat FFF 用 5mm 准直器（p=0.013）和 Cyberknife（p=0.03）在保护健康肝脏方面具有优势。PT 的 FOV 和 FOVR 较低（p<0.001）。3 年 FFLR 为 83%。经典放射性肝损伤（任何等级的 RILD）影响了 2 例患者。
Cyberknife 和 V-MAT FFF 用 5mm 准直器比 V-MAT FF 用 10mm 准直器保护更多的肝脏。与光子相比，PT 保护更多的肝脏。FOV 和 FOVR 允许对健康组织保护性能进行定量分析，还可以根据剂量衰减来评估计划的质量。
