The Accuracy of Quantitative Lutetium-177 Single Photon Emission Computed Tomography Imaging and the Role for Partial-Volume Corrections in Clinical Practice: A Systematic Review

Background Accurate quantification of lutetium-177 (177Lu) radioactivity in SPECT/CT imaging is essential for a further development of 177Lu-based peptide receptor radionuclide therapy (PRRT) for neuroendocrine tumours and metastatic prostate cancer. Purpose This review provides an overview on the accuracy of quantitative 177Lu SPECT/CT imaging, identifies methods for an improved accuracy when imaging small volumes subject to partial-volume effects (PVEs), and assesses the role for partial-volume corrections (PVCs) in clinical practice.

A systematic review was conducted according to PRISMA guidelines. MEDLINE, EMBASE, and Web of Science databases were searched with no language restrictions. Original studies explicitly reporting on the accuracy of 177Lu activity quantifications in physical SPECT/CT measurements were included.

The literature search identified 616 records, of which 46 studies were included for analysis. Percentage errors of quantifications were found to constitute a large range (−102% to 285%). The recovery of 177Lu activity from small volumes is inherently limited by PVEs. The application of PVCs has led to improvements in the accuracy and precision of quantifications on small volumes in phantom imaging.

The accuracy of 177Lu activity quantifications in SPECT/CT imaging is subject to large variability and will be degraded by PVEs when imaging small volumes. The data suggests that the implementation of standardised procedures and PVCs may lead to an improved accuracy and precision of quantitative 177Lu SPECT/CT imaging in clinical practice, thereby allowing the further development of 177Lu-based PRRT. Competing Interest Statement The authors have declared no competing interest. Funding Statement Julian van Oorschodt acknowledges financial support from the Hendrik Muller Foundation (Stichting dr. Hendrik Mullers Vaderlandsch Fonds) and the Foundation of Renswoude (Stichting de Fundatie van de Vrijvrouwe van Renswoude) and the receiving of a Holland Scholarship. Additionally The University of Sydney sponsored Julian providing access to its research resources throughout the course of the study. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data availability The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.