Fourteen patients referred for evaluation for PSMA-RLT received [68 Ga]Ga-PSMA-11 PET/CT at 1 h p.i. with a standard activity of 150 MBq and an additional low-dose 2-[18F]FDG PET/CT with 40 MBq 1 h thereafter using a long-axial field-of-view PET/CT system in a single sitting and as per institutional protocol. Scans were scrutinized by two experienced nuclear medicine physicians for mismatch findings.
The combined protocol identified additional lesions with low or absent PSMA-expression but high FDG-avidity in 1/14 (7%) patients. The protocol was easily implemented and well tolerated by all patients.
Additional low-dose 2-[18F]FDG-PET/CT is feasible as part of a same-day imaging protocol and can help reveal lesions of low PSMA avidity as part of therapy assessment for [177Lu]-PSMA radioligand therapy and demonstrates higher sensitivity compared to [68 Ga]Ga-PSMA-11 PET/CT alone in some patients.
方法:接受PSMA-RLT评估的14例患者在1hp.i.时接受了[68Ga]Ga-PSMA-11PET/CT,标准活性为150MBq,然后在1h后使用长轴视野PET/CT系统并根据机构方案进行了40MBq的低剂量2-[18F]FDGPET/CT。扫描由两名经验丰富的核医学医生仔细检查,以发现不匹配的结果。
结果:联合方案在1/14(7%)患者中发现了PSMA表达低或缺失但FDG代谢高的其他病变。该方案很容易实施,所有患者都能很好地耐受。
结论:作为当天成像方案的一部分,额外的低剂量2-[18F]FDG-PET/CT是可行的,并且可以帮助揭示低PSMA亲和力的病变,作为[177Lu]-PSMA放射性配体治疗的治疗评估的一部分,并且在某些患者中与单独的[68]Ga-PSMA-11PET/CT相比显示出更高的敏感性。