Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
Department of Oncology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
J Nucl Med. 2019 Oct;60(10):1406-1413. doi: 10.2967/jnumed.118.225235. Epub 2019 Mar 22.
This study aimed to compare different image-based methods for bone marrow dosimetry and study the dose-response relationship during treatment with Lu-DOTATATE in patients with and without skeletal metastases. This study included 46 patients with advanced neuroendocrine tumors treated with at least 2 fractions of Lu-DOTATATE at Sahlgrenska University Hospital. High- and low-uptake compartments were automatically outlined in planar images collected at 2, 24, 48, and 168 h after injection. The bone marrow absorbed doses were calculated from the cross doses of the high- and low-uptake compartments and the self-dose, using the time-activity concentration curve for the low-uptake compartment. This time-activity concentration curve was adjusted using a fixed constant of 1.8 for the planar dosimetry method and using the activity concentrations in vertebral bodies in SPECT images at 24 h after injection of Lu-DOTATATE in 4 hybrid methods: L4-SPECT used the activity concentration in the L4 vertebra, whereas V-SPECT, L-SPECT, and T-SPECT used the median activity concentration in all visible vertebrae, lumbar vertebrae, and thoracic vertebrae, respectively. Using the planar method, L4-SPECT, V-SPECT, L-SPECT, and T-SPECT, the estimated median bone marrow absorbed doses were 0.19, 0.36, 0.40, 0.39, and 0.46 Gy/7.4 GBq, respectively, with respective ranges of 0.12-0.33, 0.15-1.44, 0.19-1.71, 0.21-1.60, and 0.18-2.12 Gy/7.4 GBq. For all methods, the bone marrow absorbed dose significantly correlated with decreased platelet counts. This correlation increased after treatment fraction 2: the Spearman correlation () were -0.49 for the planar method, -0.61 for L4-SPECT, -0.63 for V-SPECT, -0.63 for L-SPECT, and -0.57 for T-SPECT. A separate analysis revealed an increased correlation for patients without skeletal metastases using the planar method ( = -0.67). In contrast, hybrid methods had poor correlations for patients without metastases and stronger correlations for patients with skeletal metastases ( = -0.61 to -0.74). The mean bone marrow absorbed doses were 3%-69% higher for patients with skeletal metastases than for patients without. The estimated bone marrow absorbed doses by image-based techniques and the correlation with platelets are influenced by the choice of measured vertebrae and the presence of skeletal metastases.
这项研究旨在比较不同的基于图像的方法进行骨髓剂量测定，并研究 Lu-DOTATATE 治疗期间有和没有骨骼转移的患者的剂量反应关系。这项研究包括 46 名在萨尔格伦斯卡大学医院接受至少 2 次 Lu-DOTATATE 治疗的晚期神经内分泌肿瘤患者。在注射后 2、24、48 和 168 小时收集的平面图像中自动勾勒出高和低摄取区室。骨髓吸收剂量是通过高和低摄取区室的交叉剂量和自身剂量计算出来的，使用低摄取区室的时间-活性浓度曲线。对于平面剂量测定方法，该时间-活性浓度曲线使用 1.8 的固定常数进行调整，对于 4 种混合方法，使用 Lu-DOTATATE 注射后 24 小时 SPECT 图像中 L4 椎体的放射性活度：L4-SPECT 使用 L4 椎体的放射性活度，而 V-SPECT、L-SPECT 和 T-SPECT 则分别使用所有可见椎体、腰椎和胸椎的中位数放射性活度。使用平面方法、L4-SPECT、V-SPECT、L-SPECT 和 T-SPECT，估计的中位数骨髓吸收剂量分别为 0.19、0.36、0.40、0.39 和 0.46 Gy/7.4GBq，范围分别为 0.12-0.33、0.15-1.44、0.19-1.71、0.21-1.60 和 0.18-2.12 Gy/7.4GBq。对于所有方法，骨髓吸收剂量与血小板计数减少显著相关。在治疗后第 2 个分数后，这种相关性增加：Spearman 相关系数（）分别为平面法-0.49、L4-SPECT-0.61、V-SPECT-0.63、L-SPECT-0.63 和 T-SPECT-0.57。单独的分析显示，对于没有骨骼转移的患者，使用平面方法的相关性增加（= -0.67）。相比之下，混合方法对于没有转移的患者相关性较差，而对于有骨骼转移的患者相关性较强（= -0.61 至 -0.74）。有骨骼转移的患者的骨髓吸收剂量平均比没有骨骼转移的患者高 3%-69%。基于图像的技术估计的骨髓吸收剂量与血小板之间的相关性受测量椎体的选择和骨骼转移的存在的影响。
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