Impact of antagonist peptides and chelators on the diagnostic performance of PET/CT using gallium-68-labeled somatostatin receptor antagonists

Objective: Different SSTR2 antagonists have been developed. This study aims to evaluate the impact of different peptides and chelators on the diagnostic performance of SSTR2 antagonists in well-differentiated NETs.Methods: In this prospective study, participants were equally randomized into 2 arms: arm A, participants would undergo a whole-body^(68)Ga-NODAGA-LM3 PET/CT scan on the first day and^(68)Ga-DOTA-LM3 PET/CT scan on the second day;arm B, participants would undergo a whole-body^(68)Ga-NODAGA-LM3 PET/CT scan on the first day and^(68)Ga-NODAGA-JR11 PET/CT scan on the second day. Biodistribution in normal organs, lesion detection ability, and tumor uptakes were compared within each arm.Results: A total of 40 participants (age, 49.5 ± 13.4, 21 men), 20 in each arm, were recruited in the study. In arm A,^(68)Ga-DOTA-LM3 showed lower background. However, the lesion detection ability (overall lesion detected, 445 vs 548;P = .005) and the lesion uptake (overall lesions SUVmax, 19.8 ± 17.2 vs 35.3 ± 28.8;P < .001) was significantly lower than those of^(68)Ga-NODAGA-LM3. In arm B, both^(68)Ga-NODAGA-LM3 and^(68)Ga-NODAGA-JR11 showed similar biodistribution and lesion uptake (SUVmax, 28.5 ± 23.8 vs 25.0 ± 20.0;P < .001) despite minor differences. The lesion detection ability was the same between these 2 tracers (overall lesion detected, 503 vs 503).Conclusions: The diagnostic performance of SSTR2 antagonists was sensitive to chelators. Both^(68)Ga-NODAGA-LM3 and^(68)Ga-NODAGA-JR11 outperformed^(68)Ga-DOTA-LM3 with higher lesion uptake and detection ability, of which^(68)Ga-NODAGA-LM3 had marginally but significantly higher lesion uptake.

Impact of antagonist peptides and chelators on the diagnostic performance of PET/CT using gallium-68 labeled somatostatin receptor antagonists

Objective:Different SSTR2 antagonists have been developed.This study aims to evaluate the impact of different peptides and chelators on the diagnostic performance of SSTR2 antagonists in well-differentiated NETs.Methods:In this prospective study,participants were equally randomized into two arms:Arm A,participants would undergo a whole-body 68Ga-NODAGA-LM3 PET/CT scan on the 1st day and 68Ga-DOTA-LM3 PET/CT scan on the 2nd day;Arm B,participants would undergo a whole-body 68Ga-NODAGA-LM3 PET/CT scan on the 1st day and 68Ga-NODAGA-JR11 PET/CT scan on the 2nd day.Biodistribution in normal organs,lesion detection ability,and tumor uptakes were compared within each Arm.Results:A total of 40 participants(age,49.5±13.4,21 men),20 in each arm,were recruited in the study.In Arm A,68Ga-DOTA-LM3 showed lower background.However,the lesion detection ability(overall lesion detected,445 versus 548,P=0.005)and the lesion uptake(overall lesions SUVmax,19.8±17.2 versus 35.3±28.8,P<0.001)was significantly lower than those of 68Ga-NODAGA-LM3.In Arm B,both 68Ga-NODAGA-LM3 and 68Ga-NODAGA-JR11 showed similar biodistribution and lesion uptake(SUVmax,28.5±23.8 versus 25.0±20.0,P<0.001)despite minor differences.The lesion detection ability was the same between these two tracers(overall lesion detected,503 versus 503).Conclusions:The diagnostic performance of SSTR2 antagonists was sensitive to chelators.Both 68Ga-NODAGA-LM3 and 68Ga-NODAGA-JR11 outperformed 68Ga-DOTA-LM3 with higher lesion uptake and detection ability,of which 68Ga-NODAGA-LM3 had marginally but significantly higher lesion uptake.