Introduction of Dosimetry on PRRT Practice. A Useful Tool to Detect Responders and Evaluate Treatment Safety

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Introduction: PRRT is a recognized salvage option for G1-G2 GEPNET. Currently, the Italian protocol (Lutathera AIFA Guidelines) consists in four fixed-dose of 177 Lu-DOTATATE. The dosimetry has recently been recognized as an important tool to guide PRRT but is not yet part of routine practice.

Aim(s): To highlight the effectiveness of dosimetry in detecting PRRT response and the safety.

Materials and methods: A 64-year woman with G1 pancreatic NET liver metastasis has undergone splenopancreasectomy (pT4 pN1) in 2016 and liver TACE in 2017. Since the hepatic lesions progressed, the patient was treated in 2018 with 177Lu-DOTATOC. A 99Tc-Tektrotyd scintigraphy was performed before PRRT to confirm significant metastatic uptake. Consequently, the patient was treated with 177Lu-DOTATOC, 7.4 GBq per 4 administrations, q8 weeks. During the first and the fourth administration four sequential SPECT-CT were performed on SIEMENS Symbia INTEVO to evaluate kidneys and metastasis. Absorbed doses calculated with OLINDA 1.1. The ECOG-PS and laboratory examinations were performed every PRRT administration; CT was performed before PRRT, after the second administration and during follow up.

Conference: 17th Annual ENETSConcerence (2020)

Presenting Author: SCALORBI F

Authors: Scalorbi F, Mazzaglia S, Maccauro M, Chiesa C, Prinzi N,

Keywords: prrt, healthy tissue and target lesion dosimetry, gastroenteropancreatic neuroendocrine tumor,