Internal Dosimetry in Patients Undergoing Peptide Receptor Radionuclide Therapy (PRRT) with 177Lu-[DOTA0-Tyr3 octerotate: A Single-Center Experience

Elahe  Mahmoudi; Mahasti Amoui; Mohammad Reza  Deevband; Elahe  Pirayesh; Mohammad Reza  Asgari; Mahdi  Ghorbani

doi:10.18502/fbt.v12i1.17731

Elahe Mahmoudi Biomedical Engineering and Medical Physics Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Mahasti Amoui Nuclear Medicine Department, Shohada-e Tajrish Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Mohammad Reza Deevband Biomedical Engineering and Medical Physics Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Elahe Pirayesh Nuclear Medicine Department, Shohada-e Tajrish Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Mohammad Reza Asgari Biomedical Engineering and Medical Physics Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Mahdi Ghorbani Biomedical Engineering and Medical Physics Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran

DOI: https://doi.org/10.18502/fbt.v12i1.17731

Keywords: Individualized Dosimetry; 177Lu-DOTA0; Tyr3-Octreotate; Neuroendocrine Tumors; Organ at Risk

Abstract

Purpose: Peptide Receptor Radionuclide Therapy (PRRT) with ¹⁷⁷Lu-DOTATATE (¹⁷⁷ Lu DOTA-TATE therapy is a form of PRRT which targets Somatostatin Receptors (SSR). It is a form of targeted drug delivery, which is applicable to treat neuroendocrine tumors. PRRT applications are continuously expanding in most departments of nuclear medicine in Iran, but the best of all, no one has studied the mean doses of organs of the patients. This research aims to specify the absorbed dose to patients for the treatment of neuroendocrine tumors using imaging with ¹⁷⁷Lu-[DOTA0-Tyr3] octerotate.

Materials and Methods: Whole body planar scintigraphy images were collected for 10 patients, which are used as the basis for the personalized patient dosimetry calculations. The patients had a mean age of 53.5 ± 12 years (ranging from 36 to 70 years) and imaging data were collected at roughly 0 to 2 hours, 4 to 6 hours, 18 to 24 hours, and 36 to 48 hours after the injection of 6401± 628.4 MBq (range of 5500 MBq-7400 MBq) of ¹⁷⁷Lu-[DOTA0-Tyr³] octerotate. Models of time-activity were established for different organs. Finally, using absorbed dose formulation and IDIAC-Dosage software, the mean absorbed dose in the organs was determined.

Results: Mean calculated dose in the kidney and liver were obtained as 0.30-0.82 mGy/ MBq, and 1.05-2.11 mGy/MBq, respectively.

Conclusion: Based on the results, PRRT therapy is a safe method for the treatment of castration-resistant neuroendocrine cancer patients in terms of patient dose. Large inter-individual differences in organ dose were discovered, highlighting the importance of patient-specific dosimetry and treatment planning in the treatment with ¹⁷⁷Lu-DOTATATE.