Experimental Approach for Optimizing Dose Regimen of 68Ga-Dotatate Pet/Ct for Neuroendocrine Tumor (Net) Imaging in Current High Sensitivity Scanners: Phantom and Patient Study; [Experimenteller Ansatz Zur Optimierung Des Dosierungsschemas Von 68Ga-Dotatate Pet/Ct Fur Die Bildgebung Neuroendokriner Tumore (Net) in Aktuellen Hochempfindlichen Scannern: Phantom- Und Patientenstudie] Publisher Pubmed



Monsef A ; Saboktakin F ; Sadeghi F ; Elhaie M ; Beheshti M ; Sheikhzadeh P
Source: Nuklearmedizin - NuclearMedicine Published:2025

Abstract

Aim This study aimed to determine the optimized scan time and injected activity regimen for clinical 68Ga DOTATATE PET/ CT in neuroendocrine tumor imaging through an experimental approach without using machine learning techniques. Methods A NEMA PET body phantom was used with Ga-68 to simulate a 9:1 sphere-to-background ratio. PET data were acquired on a high-sensitivity scanner at various scan times (15–300 s/ bed). For each scan time, coefficient of variation (COV) and contrast-to-noise ratio (CNR) were calculated. The minimum scan time (Tmin) needed to meet the Rose Criterion (CNR > 5) for the smallest sphere was identified. This Tmin was then applied to patient scans with neuroendocrine tumors (originally acquired at 120 s/bed) to evaluate image quality and determine an optimized activity regimen for clinical 68Ga-DOTATATE PET imaging. Results Phantom experiments showed that a COVmax of 20 % is the highest acceptable noise level for detecting the smallest lesions, corresponding to a minimum scan time of about 1 minute per bed position. Patient image analysis confirmed that all tumors visible at routine scan times were still detectable at this minimum duration. This supports the use of a lower activity regimen (~1 MBq/kg), which can reduce patient radiation exposure compared to the standard 1.85 MBq/kg protocol. Conclusion This work demonstrated that scan time and activity for 68Ga-DOTATATE NET imaging can be significantly minimized without compromising image interpretation and quantification. © 2025. Thieme. All rights reserved.