A personal acquisition time regimen of 68Ga-DOTATATE total-body PET/CT in patients with neuroendocrine tumor (NET): A feasibility study.

Abstract Purpose: To propose a personal acquisition time regimen of 68Ga-DOTATATE total-body positron emission tomography-computed tomography (PET/CT) for acceptable and constant image quality of patients with neuroendocrine tumors (NETs).Methods: A development cohort consisting of 19 consecutive patients with full activity (88.7-204.9 MBq/kg) was used to establish the acquisition time regimen. The liver SNR (signal-to-noise ratio, SNRL) was normalized (SNRnorm) by the product of injected activity and acquisition time. Fitting of SNRnorm against body mass (BM) in linear correlation was performed. Subjective assessment of image quality was performed using a 5-point Likert scale to determine the acceptable threshold of SNRL, and an optimized acquisition regimen based on BM was proposed and validated using a cohort of 57 NET patients with half activity (66.9±11.3 MBq, 1.0±0.1 MBq/kg) in a fixed acquisition time regimen.Results: The linear correlation (R2=0.63) between SNRnorm and BM was SNRnorm=-0.01*BM+1.50. The threshold SNRL of acceptable image quality was 11.2. The patient-specific variable acquisition time regimen was then determined as t (min) = 125.4/(injective activity)*(-0.01*BM+1.50)2. Based on the regimen, the average acquisition time for acceptable image quality in the validation cohort was 2.99±0.91 min, ranging from 2.18 to 6.35 min, which was reduced by 36.50%~78.20% compared with the fixed acquisition time of 10 min. Subjective evaluation showed that acceptable image quality could be obtained at 3.00 min in the low-activity group, with an average score of 3.44±0.53 (kappa = 0.97, 95% CI: 0.96~0.98). Bland–Altman analysis revealed good agreement between the proposed regimen and the fixed acquisition time cohort.Conclusion: A personal acquisition time regimen was proposed and validated for NET patients for 68Ga-DOTATATE total-body PET/CT imaging. Based on the regimen, the image quality is feasible for a constant level, independent of body mass, with reasonable acquisition time.