Prvulovich E M, Lonn A H, Bomanji J B, Jarritt P H, Ell P J
Institute of Nuclear Medicine, University College London Medical School, UK.
Nucl Med Commun. 1997 Mar;18(3):207-18. doi: 10.1097/00006231-199703000-00004.
For attenuation correction (AC) of 201Tl myocardial perfusion images, an accurate attenuation map is required. This study assessed whether prolonged transmission scanning is required in obese compared to normal-sized patients. Twenty-nine obese patients (mean body mass index 33 kg m-2) underwent sequential emission/transmission imaging for AC using an L-shaped, dual-headed gamma camera fitted with two 153Gd scanning line sources. Transmission data were acquired for 5 s per view (scan time for normal-sized patients) and for 10 s per view and used to reconstruct individual attenuation maps. Emission data were reconstructed using each attenuation map in turn to produce attenuation-corrected images (AC5 and AC10). Tracer distribution in the AC5 and AC10 images was compared by two observers blinded to study type. For each data set, count density was measured in 17 segments of a polar plot and segmental uptake expressed relative to study maximum. Although myocardial count density was low on the 5 s per view transmission images (0.5-13.0 and 3.0-14.0 counts per pixel in the anteroposterior and lateral projections respectively), no significant differences in tracer distribution were seen between the AC5 and AC10 images and these were reported identically. In addition, the mean segmental relative uptake values were similar (P > 0.05) for corresponding segments of the AC5 and AC10 images. We conclude that prolonged transmission scanning is not required in obese compared to normal-sized patients. The transmission scanning protocol used in normal-sized patients is applicable across a wide patient weight range.
对于201Tl心肌灌注图像的衰减校正（AC），需要准确的衰减图。本研究评估了与正常体型患者相比，肥胖患者是否需要延长发射扫描时间。29名肥胖患者（平均体重指数33 kg/m²）使用配备两个153Gd扫描线源的L型双头伽马相机进行了连续发射/发射扫描以进行AC。每个视角的发射数据采集5秒（正常体型患者的扫描时间）和10秒，并用于重建个体衰减图。依次使用每个衰减图重建发射数据，以生成衰减校正图像（AC5和AC10）。由对研究类型不知情的两名观察者比较AC5和AC10图像中的示踪剂分布。对于每个数据集，在极坐标图的17个节段中测量计数密度，并将节段摄取量相对于研究最大值表示。尽管在每个视角5秒的发射图像上心肌计数密度较低（前后位和侧位投影中分别为0.5-13.0和3.0-14.0计数/像素），但在AC5和AC10图像之间未观察到示踪剂分布的显著差异，并且报告结果相同。此外，AC5和AC10图像相应节段的平均节段相对摄取值相似（P>0.05）。我们得出结论，与正常体型患者相比，肥胖患者不需要延长发射扫描时间。正常体型患者使用的发射扫描方案适用于广泛的患者体重范围。
