Introduction: Radiation planning approaches for liver radiation often do not consider the regional variation that can exist in liver function. This study dosimetrically compares functional liver image-guided hepatic therapy (FLIGHT) to standard stereotactic body radiation therapy (SBRT) plans. In the FLIGHT plans, functional data from hepatobiliary iminodiacetic acid (HIDA) single photon emission computed tomography (SPECT) scans serve as a road map to guide beam arrangement. While meeting the same target volume coverage, plans are optimized to reduce dose to high-functioning liver. Materials and Methods: The study included 10 patients with hepatocellular carcinoma (HCC) with baseline HIDA SPECT imaging. Standard SBRT plans which did not systematically incorporate these scans had previously been completed on all 10 plans. Retrospectively, FLIGHT plans were created based on the use of contours of relative liver function from the HIDA SPECT as avoidance structures. Resulting dose to each relative functional liver structure was examined and compared qualitatively and using Wilcoxin rank-sum tests. Target coverage, doses to organs at risk (OARs), conformity index (CI), and gradient index (GI) were also evaluated. Results: While maintaining the same target coverage, FLIGHT plans reduced the mean dose to the high functioning liver by a median of 3.0 Gy (range 0.7 to 4.6 Gy), which represented a 31.4% mean reduction compared to standard planning. FLIGHT plans reduced the volume of high functioning liver receiving 15 Gy by a mean of 59.3 cc (range 7 to 170 cc), for a mean reduction of 41.9%. The mean dose to areas of liver function defined by 25% to 100% and 50% to 100% maximum was reduced with FLIGHT from 10.5 Gy to 8.5 Gy and from 10.5 Gy to 7.5 Gy, respectively (p < 0.005 for both comparisons). The FLIGHT plans’ mean CI and GI did not differ significantly from the standard plans’ (p = 0.721 and 0.169, respectively). Conclusion: FLIGHT SBRT allows for field design and plan optimization individualized to a patient's baseline regional liver function to maximize hepatic functional reserve. This personalized approach is achieved without compromising target coverage or OAR sparing.

简介：肝辐射的辐射规划方法通常不考虑肝功能中可能存在的区域差异。这项研究从剂量学上比较了功能性肝脏影像引导肝治疗（FLIGHT）与标准立体定向身体放射治疗（SBRT）计划。在FLIGHT计划中，来自肝胆碱亚氨基二乙酸（HIDA）单光子发射计算机断层扫描（SPECT）扫描的功能数据可作为指导光束布置的路线图。在满足相同目标体积覆盖率的同时，优化计划以减少对高功能肝的剂量。材料和方法：该研究纳入了10例具有基线HIDA SPECT成像的肝细胞癌（HCC）患者。尚未在所有10个计划上完成未系统地合并这些扫描的标准SBRT计划。回顾性地，基于使用HIDA SPECT中相对肝功能的轮廓作为避让结构来创建FLIGHT计划。使用Wilcoxin秩和检验检查并定性比较了每个相对功能肝结构的最终剂量。还评估了靶标覆盖率，高危器官剂量（OAR），合格指数（CI）和梯度指数（GI）。结果：在保持相同的目标覆盖率的同时，FLIGHT计划将高功能肝的平均剂量降低了3.0 Gy（0.7至4.6 Gy），中值与标准计划相比降低了31.4％。FLIGHT计划将接受15 Gy的高功能肝的体积平均减少了59.3 cc（范围从7到170 cc），平均减少了41.9％。FLIGHT分别将最大肝功能区定义的平均剂量从10.5 Gy降低到8.5 Gy，将最大肝功能区的平均剂量从50％降低到7.5 Gy（两个比较均p <0.005）。飞行计划的平均CI和GI与标准计划没有显着差异（分别为p = 0.721和0.169）。结论：FLIGHT SBRT允许根据患者的基线区域肝脏功能进行个性化的现场设计和计划优化，以最大化肝脏功能储备。实现这种个性化方法不会影响目标覆盖范围或OAR备用量。