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EANM dosimetry committee recommendations for dosimetry of 177Lu-labelled somatostatin-receptor- and PSMA-targeting ligands

European nuclear medicine physicists set out a detailed, agreed method for measuring exactly how much radiation dose a patient's kidneys and tumours actually receive during lutetium-177 treatments, so that dosing can eventually be tailored to the individual rather than fixed for everyone.

This EANM Dosimetry Committee document provides detailed, practical recommendations for performing patient-specific dosimetry during therapy with 177Lu-labelled somatostatin-receptor ligands (for neuroendocrine tumours) and 177Lu-PSMA ligands (for prostate cancer). It specifies imaging protocols (typically three well-separated SPECT/CT time points per cycle for kidney and tumour dosimetry), segmentation and recovery-correction methods, and reports the underlying pharmacokinetic and dosimetric literature: mean kidney absorbed doses of roughly 0.54-1.00 Gy/GBq for 177Lu-somatostatin-receptor ligands and 0.4-0.8 Gy/GBq for 177Lu-PSMA, and tumour absorbed doses typically 1-8 Gy/GBq, with inter-patient variability up to ninefold for 177Lu-PSMA.

The guideline notes that because 177Lu-PSMA-617 (Pluvicto) is approved for use at a fixed activity per cycle (7.4 GBq every 6 weeks), patient-specific dosimetry is not mandatory for on-label use, but the committee encourages its practice to build the evidence base for eventually personalising dose - an approach already used for decades in dosimetry-led PRRT centres.

This document, alongside the companion joint EANM/SNMMI 177Lu-PSMA-RLT procedure guideline, is the reference clinical physicists and nuclear medicine physicians use to standardise dosimetry methodology across centres, a prerequisite for any future trial of dosimetry-personalised versus fixed-activity radioligand therapy.

GuidelineChanged practice182 citations

Authors

Sjögreen Gleisner K, Chouin N, Gabina PM, Cicone F, Gnesin S, et al.

Published

European Journal of Nuclear Medicine and Molecular Imaging, 2022

Full text

doi:10.1007/s00259-022-05727-7 PubMed 35284969

Findings

Recommends kidney dosimetry using SPECT/CT at three well-separated time points between day 1 and day 7 after each therapy cycle.
Reports mean absorbed kidney doses of roughly 0.54-1.00 Gy/GBq for 177Lu-somatostatin-receptor ligands and 0.4-0.8 Gy/GBq for 177Lu-PSMA.
Reports mean tumour absorbed doses of approximately 1-8 Gy/GBq, with up to ninefold inter-patient variability for 177Lu-PSMA (range 0.09-0.84 Gy/GBq in one cited series).
Notes that patient-specific dosimetry is not mandatory for on-label 177Lu-PSMA-617 use, since it is approved at a fixed per-cycle activity.

What it means

This document standardises how hospitals measure the actual radiation dose reaching a patient's kidneys and tumours during lutetium-177 treatment, laying the groundwork for shifting from a one-dose-fits-all schedule to treatment doses tailored to each patient's biology.

Caveats

Journal metadata note: the article was published in the European Journal of Nuclear Medicine and Molecular Imaging (2022;49(6):1778-1809); recorded here under Journal of Nuclear Medicine as the nearest catalogued match, so the DOI and PMID should be treated as authoritative for sourcing.
Recommendations are methodological guidance, not a mandate; dosimetry uptake still varies widely between centres and countries.
Absorbed-dose ranges cited are drawn from the pooled literature the committee reviewed, not from a single new dataset.