Nuclear Cardiology, Centre Cardiologique du Nord (CCN), Saint-Denis, Paris, France.
J Nucl Cardiol. 2020 Jun;27(3):737-747. doi: 10.1007/s12350-018-1452-z. Epub 2018 Nov 26.
We studied the impact of technetium-99m (Tc) in the thallium-201 (Tl) energy window (70 keV) to determine if CZT cardiac cameras allow us to perform simultaneous dual-isotope acquisition for myocardial perfusion imaging.
We included 117 consecutive patients. We injected 0.7 MBq/kg of Tl at stress, performed the first scan (image T1), then injected at rest 2 MBq/kg of Tc-tetrofosmin and immediately acquired a second scan with reconstruction in the energy window of thallium (image T2). A corrected thallium image was created by the subtraction of Tc downscattered photons (image TS). We compared spectra, image quality, and semiquantitative scores on T1, T2, and TS images.
Though T2 images were of worse quality, TS images were of equal quality compared to T1 images in most cases. Scores show an underestimation of abnormalities in 20% of patients on T2 images and in 10% on TS images.
Despite the improved energy resolution of CZT cameras, downscatter of technetium in the Tl window leads to an underestimation of the pathological territory in 10% to 20% of cases. It does not allow us to use simultaneous dual-isotope acquisition in clinical practice without additional tools for scatter correction.
我们研究了锝-99m（Tc）在铊-201（Tl）能量窗（70keV）中的影响，以确定 CZT 心脏相机是否允许我们同时进行两种同位素的心肌灌注成像采集。
我们纳入了 117 例连续患者。在应激时注射 0.7MBq/kg 的 Tl，进行第一次扫描（图像 T1），然后在休息时注射 2MBq/kg 的 Tc-四氮甲烷，并立即在 Tl 能量窗中进行第二次扫描和重建（图像 T2）。通过减去 Tc 散射光子（图像 TS），创建校正的铊图像。我们比较了 T1、T2 和 TS 图像的光谱、图像质量和半定量评分。
尽管 T2 图像质量较差，但在大多数情况下，TS 图像的质量与 T1 图像相当。评分显示，在 20%的患者中 T2 图像低估了异常，在 10%的患者中 TS 图像低估了异常。
尽管 CZT 相机的能量分辨率有所提高，但 Tl 窗口中的 Tc 散射会导致在 10%至 20%的病例中对病理性区域的低估。它不允许我们在没有散射校正附加工具的情况下在临床实践中同时进行双同位素采集。
