Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
University of Texas MD Anderson Cancer Center UT Health Houston Graduate School of Biomedical Sciences, Houston, Texas, USA.
J Appl Clin Med Phys. 2022 Dec;23(12):e13734. doi: 10.1002/acm2.13734. Epub 2022 Jul 30.
To investigate the accuracy and biases of predicted lung shunt fraction (LSF) and lung dose (LD) calculations via Tc-macro-aggregated albumin ( Tc-MAA) planar imaging for treatment planning of Y-microsphere radioembolization.
LSFs in 52 planning and LDs in 44 treatment procedures were retrospectively calculated, in consecutive radioembolization patients over a 2 year interval, using Tc-MAA planar and SPECT/CT imaging. For each procedure, multiple planar LSFs and LDs were calculated using different: (1) contours, (2) views, (3) liver Tc-MAA shine-through compensations, and (4) lung mass estimations. The accuracy of each planar-based LSF and LD methodology was determined by calculating the median (range) absolute difference from SPECT/CT-based LSF and LD values, which have been demonstrated in phantom and patient studies to more accurately and reliably quantify the true LSF and LD values.
Standard-of-care LSF using geometric mean of lung and liver contours had median (range) absolute over-estimation of 4.4 percentage points (pp) (0.9 to 11.9 pp) from SPECT/CT LSF. Using anterior views only decreased LSF errors (2.4 pp median, -1.1 to +5.7 pp range). Planar LD over-estimations decreased when using single-view versus geometric-mean LSF (1.3 vs. 2.6 Gy median and 7.2 vs. 18.5 Gy maximum using 1000 g lung mass) but increased when using patient-specific versus standard-man lung mass (2.4 vs. 1.3 Gy median and 11.8 vs. 7.2 Gy maximum using single-view LSF).
Calculating planar LSF from lung and liver contours of a single view and planar LD using that same LSF and 1000 g lung mass was found to improve accuracy and minimize bias in planar lung dosimetry.
通过 Tc-巨聚合白蛋白（Tc-MAA）平面成像来研究钇-90 微球放射性栓塞治疗计划中预测肺分流分数（LSF）和肺剂量（LD）计算的准确性和偏差。
在过去 2 年的时间里，回顾性地对 52 个计划中的 LSF 和 44 个治疗过程中的 LD 进行了计算，这些患者连续接受了放射性栓塞治疗。对于每个过程，使用 Tc-MAA 平面和 SPECT/CT 成像，使用不同的：（1）轮廓，（2）视野，（3）肝脏 Tc-MAA 透照补偿，（4）肺质量估计值，计算了多个平面 LSF 和 LD。通过计算来自 SPECT/CT 基础 LSF 和 LD 值的中位数（范围）绝对差值来确定每种基于平面的 LSF 和 LD 方法的准确性，这些差值已在体模和患者研究中得到证实，可以更准确和可靠地量化真实的 LSF 和 LD 值。
使用肺和肝轮廓的几何平均值的标准护理 LSF 与 SPECT/CT LSF 相比，中位数（范围）绝对高估了 4.4 个百分点（pp）（0.9 到 11.9 pp）。仅使用前视图可以减少 LSF 误差（中位数 2.4 pp，-1.1 到+5.7 pp 范围）。当使用单视图与几何平均值 LSF 相比时，平面 LD 高估减少（中位数 1.3 与 2.6 Gy，使用 1000g 肺质量时最大为 7.2 与 18.5 Gy），但当使用患者特定与标准肺质量相比时，平面 LD 高估增加（中位数 2.4 与 1.3 Gy，使用单视图 LSF 时最大为 11.8 与 7.2 Gy）。
发现从单个视图的肺和肝轮廓计算平面 LSF，并使用相同的 LSF 和 1000g 肺质量计算平面 LD，可以提高平面肺剂量学的准确性并最小化偏差。
