EANM dosimetry committee series on standard operational procedures: a unified methodology for 99mTc-MAA pre- and 90Y peri-therapy dosimetry in liver radioembolization with 90Y microspheres

Carlo Chiesa; Katarina Sjogreen-Gleisner; Stephan Walrand; Lidia Strigari; Glenn Flux; Jonathan Gear; Caroline Stokke; Pablo Minguez Gabina; Peter Bernhardt; Mark Konijnenberg

doi:10.1186/s40658-021-00394-3

EANM dosimetry committee series on standard operational procedures: a unified methodology for ^99mTc-MAA pre- and ⁹⁰Y peri-therapy dosimetry in liver radioembolization with ⁹⁰Y microspheres

EJNMMI Phys. 2021 Nov 12;8(1):77. doi: 10.1186/s40658-021-00394-3.

Authors

Affiliations

¹ Nuclear Medicine Unit, Foundation IRCCS Istituto Nazionale Tumori, Milan, Italy.
² Department of Medical Radiation Physics, Lund University, Lund, Sweden.
³ Nuclear Medicine, Molecular Imaging, Radiotherapy and Oncology Unit (MIRO), IECR, Université Catholique de Louvain, Brussels, Belgium.
⁴ Medical Physics Division, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy.
⁵ Joint Department of Physics, Royal Marsden Hospital & Institute of Cancer Research, Sutton, UK.
⁶ Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway.
⁷ Department of Medical Physics and Radiation Protection, Gurutzeta/Cruces University Hospital, Barakaldo, Spain.
⁸ Department of Radiation Physics, Institute of Clinical Science, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
⁹ Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden.
¹⁰ Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands. M.konijnenberg@erasmusmc.nl.

Abstract

The aim of this standard operational procedure is to standardize the methodology employed for the evaluation of pre- and post-treatment absorbed dose calculations in ⁹⁰Y microsphere liver radioembolization. Basic assumptions include the permanent trapping of microspheres, the local energy deposition method for voxel dosimetry, and the patient-relative calibration method for activity quantification.The identity of ^99mTc albumin macro-aggregates (MAA) and ⁹⁰Y microsphere biodistribution is also assumed. The large observed discrepancies in some patients between ^99mTc-MAA predictions and actual ⁹⁰Y microsphere distributions for lesions is discussed. Absorbed dose predictions to whole non-tumoural liver are considered more reliable and the basic predictors of toxicity. Treatment planning based on mean absorbed dose delivered to the whole non-tumoural liver is advised, except in super-selective treatments.Given the potential mismatch between MAA simulation and actual therapy, absorbed doses should be calculated both pre- and post-therapy. Distinct evaluation between target tumours and non-tumoural tissue, including lungs in cases of lung shunt, are vital for proper optimization of therapy. Dosimetry should be performed first according to a mean absorbed dose approach, with an optional, but important, voxel level evaluation. Fully corrected ^99mTc-MAA Single Photon Emission Computed Tomography (SPECT)/computed tomography (CT) and ⁹⁰Y TOF PET/CT are regarded as optimal acquisition methodologies, but, for institutes where SPECT/CT is not available, non-attenuation corrected ^99mTc-MAA SPECT may be used. This offers better planning quality than non dosimetric methods such as Body Surface Area (BSA) or mono-compartmental dosimetry. Quantitative ⁹⁰Y bremsstrahlung SPECT can be used if dedicated correction methods are available.The proposed methodology is feasible with standard camera software and a spreadsheet. Available commercial or free software can help facilitate the process and improve calculation time.

Keywords: 90Y PET; 90Y microspheres; 99mTc-MAA; Liver dosimetry; Lung shunt; Prospective/retrospective dosimetry; Radioembolization dosimetry; Tumour dosimetry.