A Prospective Study of Quantitative SPECT/CT for Evaluation of Lung Shunt Fraction Before SIRT of Liver Tumors
A Prospective Study of Quantitative SPECT/CT for Evaluation of Lung Shunt Fraction Before SIRT of Liver Tumors
复制标题
DOI：
10.2967/jnumed.117.205203
复制
发表时间：
2018-09-01
影响因子：
9.3
通讯作者：
la Fougere, Christian
中科院分区：
文献类型：
--
作者：
Dittmann, Helmut;Kopp, Daniel;la Fougere, Christian
在肝脏选择性内放疗（SIRT）之前使用Tc-99 m-MAA成像估计肺分流分数（LSF），以降低肺照射的风险。通常，在将Tc-99 m-MAA注射到肝动脉中之后获得平面扫描。然而，这种方法的有效性受到肝脏和肺组织之间的衰减差异以及器官分割不准确的限制。本研究的目的是在前瞻性临床队列中评价定量SPECT/CT用于LSF评估。方法：连续50例拟接受SIRT的患者在注射Tc-99 m-MAA后1 h内使用SPECT/CT γ照相机进行成像。在前视图和后视图中采集肺和肝区域的平面扫描，然后进行胸部和腹部的SPECT/CT扫描。使用专用软件校正发射数据的散射、衰减和分辨率恢复。为了定量肺、肝、膀胱和胸腹体其余部分中的放射性浓度，在SPECT/CT图像上定义了感兴趣体积。Tc-99 m-MAA浓度计算为注射剂量百分比（%ID）。结果：肝脏和肺中的平均Tc-99 m-MAA摄取仅占79% ID，而身体其余部分中存在13.1% ID。在所有患者中，通过平面扫描计算的LSF占中位数6.8%（范围，3.4%-32.3%），而SPECT/CT定量显示LSF估计值显著较低，中位数为1.9%（范围，0.8%-15.7%）（P < 0.0001，Wilcoxon检验）。在平面成像的基础上，50例患者中有10例必须考虑剂量减少甚至SIRT禁忌症，因为他们的LSF计算为10%或更高。相比之下，SPECT/CT定量显示50例患者中仅2例存在大量分流。结论：定量SPECT/CT显示LSF明显低于平面成像。因此，肺实质的最终剂量可能低于常规假设。但是，必须对SPECT/CT衍生剂量范围的安全性进行评价。
The lung shunt fraction (LSF) is estimated using Tc-99m-macroaggregated albumin (Tc-99m-MAA) imaging before selective internal radiotherapy (SIRT) of the liver to reduce the risk of pulmonary irradiation. Generally, planar scans are acquired after injection of Tc-99m-MAA into the hepatic artery. However, the validity of this approach is limited by differences in attenuation between liver and lung tissue as well as inaccurate segmentation of the organs. The aim of this study was to evaluate quantitative SPECT/CT for LSF assessment in a prospective clinical cohort. Methods: Fifty consecutive patients intended to undergo SIRT were imaged within 1 h after injection of Tc-99m-MAA using a SPECT/CT gamma-camera. Planar scans of the lung and liver region were acquired in anterior and posterior views, followed by SPECT/CT scans of the thorax and abdomen. Emission data were corrected for scatter, attenuation, and resolution recovery using dedicated software. To quantify the radioactivity concentration in the lung, liver, urinary bladder and remainder of the thoracoabdominal body, volumes of interest were defined on the SPECT/CT images. Tc-99m-MAA concentrations were calculated as percentage injected dose (%ID). Results: Mean Tc-99m-MAA uptake in liver and lung accounted for only 79 %ID, whereas 13.1 % ID was present in the remainder of the body. In all patients, LSF as calculated from planar scans accounted for a median of 6.8% (range, 3.4%-32.3%), whereas the SPECT/CT quantitation revealed significantly lower LSF estimates, at a median of 1.9% (range, 0.8%15.7%) (P < 0.0001, Wilcoxon test). On the basis of planar imaging, dose reduction or even contraindications to SIRT had to be considered in 10 of 50 patients, as their LSF was calculated at 10% or more. In contrast, SPECT/CT quantitation showed substantial shunting in only 2 of the 50 patients. Conclusion: Quantitative SPECT/CT reveals that the LSF is considerably lower than shown on planar imaging. Thus, the resulting dose to the lung parenchyma may be less than conventionally assumed. However, the safety of the SPECT/CT-derived dose range will have to be evaluated.