Department of Radiology, Toyohashi Municipal Hospital, Aichi.
Department of Quantum Medical Technology, Graduate School of Medical Sciences, Kanazawa University, Ishikawa.
Nucl Med Commun. 2021 Dec 1;42(12):1404-1416. doi: 10.1097/MNM.0000000000001480.
Quantitative single-photon emission computed tomography (SPECT) with computed tomography (SPECT/CT) is known to improve diagnostic performance. Although SPECT-alone systems are used widely, accurate quantitative SPECT using these systems is challenging. This study aimed to improve the accuracy of quantitative bone SPECT of the lumbar spine with the SPECT-alone system.
The cross-calibration factor (CCF) was measured using three kinds of phantoms and the optimal values were determined. The recovery coefficient with and without attenuation and scatter correction (ACSC) were compared. Bone SPECT/CT was performed on 93 consecutive patients with prostate cancer, and the standardized uptake values (SUVs) were compared using the respective CCFs. The first 60 patients were classified according to body weight, and the correlation coefficient between SUVs with and without ACSC were calculated; the slopes were defined as body weight-based coefficients (BWCs). In the remaining 33 patients, the SUV was adjusted according to BWC, and the accuracy of the adjustment was verified.
The quantitative SPECT values obtained from the CCF using SIM2 bone phantom showed nearly accurate radioactivity concentrations, even without ACSC. The recovery coefficients with and without ACSC were similar. Unadjusted SUVs with and without ACSC were strongly correlated; however, SUVs without ACSC were significantly higher than those with ACSC (P < 0.0001). The mean difference between the SUVs with and without ACSC disappeared when the SUVs without ACSC were adjusted by BWC (P = 0.9814).
Our cross-calibration method for quantitative bone SPECT enables interpretation with a harmonized SUV even in SPECT-alone systems.
定量单光子发射计算机断层扫描（SPECT）与计算机断层扫描（SPECT/CT）结合可提高诊断性能。虽然单独使用 SPECT 系统的情况很常见，但使用这些系统进行准确的定量 SPECT 具有一定挑战性。本研究旨在提高单独使用 SPECT 系统进行腰椎骨定量 SPECT 的准确性。
使用三种模型测量了交叉校准因子（CCF）并确定了最佳值。比较了有和没有衰减和散射校正（ACSC）的恢复系数。对 93 例连续前列腺癌患者进行了 SPECT/CT 检查，并使用各自的 CCF 比较了标准化摄取值（SUV）。根据体重将前 60 例患者进行分类，并计算了有无 ACSC 的 SUV 之间的相关系数；斜率定义为基于体重的系数（BWC）。在其余 33 例患者中，根据 BWC 调整 SUV，并验证调整的准确性。
使用 SIM2 骨模型的 CCF 获得的定量 SPECT 值即使没有 ACSC 也显示出几乎准确的放射性浓度。有无 ACSC 的恢复系数相似。有无 ACSC 的 SUV 之间具有很强的相关性，但没有 ACSC 的 SUV 明显高于有 ACSC 的 SUV（P <0.0001）。当没有 ACSC 的 SUV 通过 BWC 进行调整时，SUV 与无 ACSC 之间的平均差异消失（P=0.9814）。
我们的定量骨 SPECT 交叉校准方法可在单独使用 SPECT 系统的情况下进行解释，即使没有 SUV 也能进行解释。
