Abstract
BACKGROUND: The aim of this study was to evaluate the efficacy of neuroendocrine neoplasms (NENs) patients treated with peptide receptor radionuclide therapy (PRRT), and to investigate the relationships among the absorbed dose of the tumor target lesions, standardized uptake value (SUV), and the therapeutic efficacy of the patients. A total of 22 NENs patients who received [(177)Lu]Lu-DOTA-TATE treatment and underwent consecutive single-photon emission computed tomography/computed tomography (SPECT/CT) imaging after drug administration were included in this study. After the SPECT/CT imaging, the volume of interest (VOI) of the target organs and the target lesions were delineated using the Hermes Internal Radiation Dosimetry (HIRD) software, and their absorbed doses were calculated. The SUV of the target lesions was measured on the reconstructed SPECT/CT fusion images. We conducted studies on the correlations between the absorbed dose, SUV, and the therapeutic efficacy of the patients respectively. RESULTS: After the patients received [(177)Lu]Lu-DOTA-TATE treatment in cycles 1 to 4, the absorbed doses of the tumor target lesions were 21.0, 16.0, 11.4, and 8.8 Gy respectively. The results of the correlations between the absorbed dose, SUV, and the therapeutic efficacy of the patients showed that both the absorbed dose and SUV had an "S"-shaped curve relationship with the tumor partial response (PR) rate. In addition, for the 1st to 4th PRRT treatments, the absorbed dose and SUV were linearly correlated with R(2) of 0.7, 0.8, 0.8, and 0.9, respectively. CONCLUSIONS: Through the calculation and analysis of the radionuclide therapy dosimetry based on the SPECT/CT images throughout the PRRT treatment of the patients, the absorbed dose and SUV of the patients can provide important dose guidance for radionuclide therapy, which is helpful to improve the treatment efficacy of the patients. TRIAL REGISTRATION: A Study Comparing Treatment With Lutetium[177Lu] Oxodotreotide Injection to Octreotide LAR in Patients With GEP-NETs, NCT05459844. Registered 5 July 2022, https://clinicaltrials.gov/study/NCT05459844?cond=NCT05459844&rank=1 .