Verrecchia-Ramos Emilie, Morel Olivier, Beauchat Valérie, Denet Sylvie, Djibo Sidikou Abdourahamane, Ginet Merwan, Pfletschinger Estelle, Teodor Luminita, Trombowsky Maud, Verdier Jeany, Vère Christelle, Retif Paul, Mahmoud Sinan Ben
CHR Metz-Thionville, Department of Medical Physics, Mercy Hospital, 1, Allée du Château, 57530, Ars-Laquenexy, France.
CHR Metz-Thionville, Department of Nuclear Medicine, Mercy Hospital, 1, Allée du Château, 57530, Ars-Laquenexy, France.
EJNMMI Phys. 2023 Mar 24;10(1):23. doi: 10.1186/s40658-023-00545-8.
Patient radioprotection in myocardial perfusion imaging (MPI)-SPECT is important but difficult to optimize. The aim of this study was to adjust injected activity according to patient size-weight or BMI-by using a cardiofocal collimator camera.
The correlation equation between size and observed counts in image was determined in patients who underwent stress Tc-99m-sestamibi MPI-SPECT/CT with a cardiofocal collimator-equipped conventional Anger SPECT/CT system. Image quality analyses by seven nuclear physicians were conducted to determine the minimum patient size-independent observed count threshold that yielded sufficient image quality for perfusion-defect diagnosis. These data generated an equation that can be used to calculate personalized activity for patients according to their size.
Analysis of consecutive patients (n = 294) showed that weight correlated with observed counts better than body mass index. The correlation equation was used to generate the equation that expressed the relationship between observed counts, patient weight, and injected activity. Image quality analysis with 50 images yielded an observed count threshold of 22,000 counts. Using this threshold means that the injected activity in patients with < 100 kg would be reduced (e.g., by 67% in 45-kg patients). Patients who are heavier than 100 kg would also benefit from the use of the threshold because although the injected activity would be higher (up to 78% for 150-kg patients), good image quality would be obtained.
This study provided a method for determining the optimal injected activity according to patient weight without compromising the image quality of conventional Anger SPECT/CT systems equipped with a cardiofocal collimator. Personalized injected activities for each patient weight ranging from 45 to 150 kg were generated, to standardize the resulting image quality independently of patient attenuation. This approach improves patient/staff radioprotection because it reduces the injected activity for < 100-kg patients (the majority of patients).
心肌灌注成像（MPI）-单光子发射计算机断层扫描（SPECT）中的患者辐射防护很重要，但难以优化。本研究的目的是通过使用心脏聚焦准直器相机，根据患者的体型-体重或体重指数（BMI）来调整注射剂量。
在接受负荷 Tc-99m-甲氧基异丁基异腈 MPI-SPECT/CT 检查的患者中，使用配备心脏聚焦准直器的传统安捷伦 SPECT/CT 系统，确定体型与图像中观察到的计数之间的相关方程。由七位核医学医师进行图像质量分析，以确定能够产生足以诊断灌注缺损的图像质量的、与患者体型无关的最小观察计数阈值。这些数据生成了一个可用于根据患者体型计算个性化注射剂量的方程。
对连续 294 例患者的分析表明，体重与观察到的计数之间的相关性优于体重指数。利用该相关方程生成了表示观察到的计数、患者体重和注射剂量之间关系的方程。对 50 幅图像进行的图像质量分析得出观察计数阈值为 22000 计数。使用该阈值意味着体重＜100 kg 的患者的注射剂量将减少（例如，45 kg 的患者减少 67%）。体重超过 100 kg 的患者也将从使用该阈值中受益，因为尽管注射剂量会更高（150 kg 的患者最高可达 78%），但仍可获得良好的图像质量。
本研究提供了一种在不影响配备心脏聚焦准直器的传统安捷伦 SPECT/CT 系统图像质量的情况下，根据患者体重确定最佳注射剂量的方法。生成了体重范围从 45 至 150 kg 的每位患者的个性化注射剂量，以使所得图像质量标准化，而不受患者衰减的影响。这种方法改善了患者/工作人员的辐射防护，因为它降低了体重＜100 kg 患者（大多数患者）的注射剂量。
