ESTIMATION OF RENAL DOSIMETRY IN [177Lu]Lu-DOTATATE TREATMENTS: COMPARISON OF THREE QUANTIFICATION METHODS USING SPECT-CT.

Abstract

In this study, we tested two simplified procedures for quantifying 177Lu-Dotatate activity to estimate renal absorbed dose. These procedures involved determining total kidney activity from a single volume slice obtained by SPECT and from mass obtained by segmenting a single computed tomography scan or from emission images. Both methods were compared to total activity quantification using voxel-by-voxel and SPECT-CT fusion imaging. Analysis of post-administration studies from six patients showed that both simplified quantification methods yielded, on average, approximately similar values ​​for mass, cumulative activity, and renal absorbed dose. The difference compared to the voxel-by-voxel method was at most 13% for absorbed dose. Although the number of patients analyzed is small, this work presented evidence that simplified methods for quantifying renal activity of 177Lu-Dotatate could be used in SPECT or hybrid SPECT-CT equipment with low-dose CT.