Bone scintigraphy with combined single-photon emission computed tomography (SPECT) and computed tomography (CT) has become widely used for the detection of bone metastases. However, calculation of the semi-quantitative standardized uptake value (SUV) requires measurement of the pre- and post-injection radioactivity of the radiopharmaceutical. This study aimed to compare measured and fixed input radioactivity values for quantitative SPECT/CT bone imaging to examine whether the fixed measurement method of radiopharmaceutical radioactivity could be used as an alternative method. Four different methods were used to quantify the Tc-99m hydroxymethylene diphosphonate input radioactivity: (A) measured pre- and post-injection radioactivity values; (B) measured pre-injection and fixed post-injection radioactivity values; (C) fixed pre-injection and measured post-injection radioactivity values; (D) fixed pre- and post-injection radioactivity values. All SPECT/CT acquisitions were analyzed using bone SPECT analysis software, and the semi-quantitative parameters (SUVpeak and SUVmean) were recorded and compared for each analytical method. Two semi-quantitative parameters showed significant differences between analytical methods A and B, A and D, and C and D. However, an additional subgroup analysis performed on patients whose median post-injection measured radioactivity value was <1.5 MBq showed no significant differences in parameters between all analytical methods. Measurement of the radiopharmaceutical radioactivity can be an alternative method because it reduces the volume of radioactivity post-injection. The simplified fixed measurement method of radiopharmaceutical radioactivity can be used as an alternative method in cases when measuring the radioactivity in quantitative bone SPECT/CT imaging is missed.

结合单光子发射计算机断层扫描 (SPECT) 和计算机断层扫描 (CT) 的骨闪烁扫描已广泛用于检测骨转移。然而，半定量标准化摄取值（SUV）的计算需要测量放射性药物注射前和注射后的放射性。本研究旨在比较定量 SPECT/CT 骨成像的测量值和固定输入放射性值，以检验放射性药物放射性的固定测量方法是否可以用作替代方法。使用四种不同的方法来量化 Tc-99m 羟亚甲基二磷酸盐输入放射性：(A) 测量注射前和注射后放射性值；(B) 测量的注射前和固定的注射后放射性值；(C) 固定的注射前和注射后测量的放射性值；(D) 固定注射前和注射后放射性值。所有 SPECT/CT 采集均使用骨 SPECT 分析软件进行分析，并记录并比较每种分析方法的半定量参数（SUVpeak 和 SUVmean）。两个半定量参数显示分析方法 A 和 B、A 和 D、C 和 D 之间存在显着差异。然而，对注射后测量放射性中值<1.5 MBq 的患者进行的额外亚组分析显示，在所有分析方法之间的参数。放射性药物放射性的测量可以是一种替代方法，因为它减少了注射后放射性的体积。简化的放射性药物放射性固定测量方法可以作为定量骨 SPECT/CT 成像中放射性测量丢失的情况下的替代方法。