Wen Jun, Zhu Yinjie, Li Lianghua, Liu Jianjun, Chen Yumei, Chen Ruohua
Department of Nuclear Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 160 Pujian Road, Shanghai, 200127, China.
Department of Urology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
Eur J Nucl Med Mol Imaging. 2022 May;49(6):2086-2095. doi: 10.1007/s00259-021-05659-8. Epub 2021 Dec 28.
Ga-PSMA PET/CT has been widely used in patients with prostate cancer. Due to the limited axial field of view of conventional PET scanners, whole-body dynamic Ga-PSMA PET/CT has not been performed. We investigated the time-activity curves (TACs) of prostate cancer pathological lesions and physiologic bladder activity to determine the optimal Ga-PSMA PET/CT imaging time by total-body (TB) PET/CT.
Dynamic TB-PET performed on 11 patients with prostate cancer was analyzed. TACs were obtained by drawing regions of interest in normal organs and pathological lesions (primary prostate lesions and lymph nodes and bone metastases). We evaluated the Ga-PSMA uptake pattern of normal organs, urinary bladder, and pathological lesions.
The urinary bladder TAC increased slowly between 180 and 330 s post-injection and then rapidly between 5.5 and 60.0 min post-injection. The pathological lesion uptake increased rapidly during the first 5 min post-injection and then slowly through the remaining 55 min. Six minutes post-injection was the optimal time with the highest pathological lesion SUV values still higher than the urinary bladder activity value. However, these prostate lesion, lymph node metastasis, and bone metastasis SUV values were one-third, one-half, and one-half the corresponding values 60 min post-injection, suggesting that early imaging might miss low PSMA uptake lesions. A minimum of 35 min post-injection was required for the pathological lesions to have SUV values similar to the corresponding values at 60 min post-injection (all P > 0.05), even though the pathological lesion SUV values showed a continuous upward trend through the 60 min.
Combining early dynamic Ga-PSMA PET (75-360 s) and conventional static imaging 60 min post-injection could avoid the urinary bladder activity interference to better detect pathological lesions and lesions with relatively low PSMA uptake. The pathological lesion SUV values at 35-59 min and 60 min post-injection were similar, so Ga-PSMA PET imaging could also be made at 35-59 min post-injection.
镓-PSMA PET/CT已广泛应用于前列腺癌患者。由于传统PET扫描仪的轴向视野有限，尚未进行全身动态镓-PSMA PET/CT检查。我们通过全身（TB）PET/CT研究了前列腺癌病理病变和生理性膀胱活动的时间-活性曲线（TAC），以确定最佳的镓-PSMA PET/CT成像时间。
分析了11例前列腺癌患者进行的动态TB-PET检查结果。通过在正常器官和病理病变（原发性前列腺病变、淋巴结和骨转移灶）中绘制感兴趣区域来获取TAC。我们评估了正常器官、膀胱和病理病变的镓-PSMA摄取模式。
注射后180至330秒膀胱TAC缓慢上升，然后在注射后5.5至60.0分钟迅速上升。病理病变摄取在注射后前5分钟迅速增加，然后在剩余55分钟内缓慢增加。注射后6分钟是最佳时间，此时病理病变的SUV值最高且仍高于膀胱活性值。然而，这些前列腺病变、淋巴结转移和骨转移的SUV值分别是注射后60分钟时相应值的三分之一、二分之一和二分之一，这表明早期成像可能会遗漏低PSMA摄取病变。尽管病理病变的SUV值在60分钟内呈持续上升趋势，但注射后至少35分钟病理病变的SUV值才与注射后60分钟时的相应值相似（所有P>0.05）。
结合早期动态镓-PSMA PET（75 - 360秒）和注射后60分钟的传统静态成像可以避免膀胱活动干扰，从而更好地检测病理病变和PSMA摄取相对较低的病变。注射后35 - 59分钟和60分钟时病理病变SUV值相似，因此镓-PSMA PET成像也可在注射后35 - 59分钟进行。
