Validation of a single time-point estimates of 177Lu-PRRT absorbed doses and impact on patient management for 192 therapies

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Introduction: Dosimetry calculation after 177Lu-DOTA-TATE Peptide Receptor Radionuclide Therapy (PRRT) enables to estimate radiation doses absorbed by normal organs and target lesions. Previously, we described a newly developed model to predict absorbed doses (ADs) from a single post-treatment study with good accuracy as compared to the standard multiple time-points protocol.

Aim(s): To validate this single time-point dosimetry model in a large number of patients and to assess whether this model maintains management decisions.

Materials and methods: SPECT/CT data obtained after PRRT of 178 consecutive patients with metastatic neuroendocrine tumors (192 treatments, 541 cycles) were retrospectively analysed for validation of the model. The predicted single time-point ADs were calculated for 187 kidneys, 47 bone marrows, 190 livers, 170 spleens and 356 tumors and were compared to those obtained using the standard multiple time-point protocol. Subsequently, the impact of the single time-point dosimetry protocol on patient management decisions was evaluated. The null hypothesis was that patient management decisions using the single time-point protocol will differ in more than 5% of therapies.

Conference:

Presenting Author:

Authors: Chicheportiche A, Krausz Y, Godefroy J, Gross D, Grozinsky-Glasberg S,

Keywords: PRRT, Dosimetry, SPECT/CT, Single time-point,