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

• Published in: EJNMMI physics 2021-11, Vol.8 (1), p.1-44, Article 77
• Main Authors: Chiesa, Carlo, Sjogreen-Gleisner, Katarina, Walrand, Stephan, Strigari, Lidia, Flux, Glenn, Gear, Jonathan, Stokke, Caroline, Gabina, Pablo Minguez, Bernhardt, Peter, Konijnenberg, Mark
• Format: Article
• Language: English
• Subjects: 90Y microspheres; 99mTc-MAA; Albumins; Annan fysik; Applied and Technical Physics; Attenuation; Bremsstrahlung; Cancer and Oncology; Cancer och onkologi; Clinical Medicine; Computational Mathematics and Numerical Analysis; Computed tomography; Dosimeters; Dosimetry; Emission analysis; Engineering; Fysik; Guideline; Imaging; Klinisk medicin; Liver; Liver dosimetry; Lung shunt; Lungs; Mathematical analysis; Medical and Health Sciences; Medicin och hälsovetenskap; Medicine; Medicine & Public Health; Methodology; Microspheres; Natural Sciences; Naturvetenskap; Nuclear Medicine; Optimization; Other Physics Topics; Photon emission; Physical Sciences; Positron emission; Prospective/retrospective dosimetry; Radioembolization dosimetry; Radiologi och bildbehandling; Radiology; Radiology, Nuclear Medicine and Medical Imaging; Software; Spreadsheets; Tc-MAA; Therapy; Tomography; Toxicity; Tumour dosimetry; Y microspheres; Y PET; Yttrium isotopes
• ISSN: 2197-7364; 2197-7364
• DOI: 10.1186/s40658-021-00394-3

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 90 Y 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 99m Tc albumin macro-aggregates (MAA) and 90 Y microsphere biodistribution is also assumed. The large observed discrepancies in some patients between 99m Tc-MAA predictions and actual 90 Y 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 99m Tc-MAA Single Photon Emission Computed Tomography (SPECT)/computed tomography (CT) and 90 Y TOF PET/CT are regarded as optimal acquisition methodologies, but, for institutes where SPECT/CT is not available, non-attenuation corrected 99m Tc-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 90 Y 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.