TY - JOUR
T1 - A multicentre and multi-national evaluation of the accuracy of quantitative Lu-177 SPECT/CT imaging performed within the MRTDosimetry project
AU - Tran-Gia, Johannes
AU - Denis-Bacelar, Ana M.
AU - Ferreira, Kelley M.
AU - Robinson, Andrew P.
AU - Calvert, Nicholas
AU - Fenwick, Andrew J.
AU - Finocchiaro, Domenico
AU - Fioroni, Federica
AU - Grassi, Elisa
AU - Heetun, Warda
AU - Jewitt, Stephanie J.
AU - Kotzassarlidou, Maria
AU - Ljungberg, Michael
AU - McGowan, Daniel R.
AU - Scott, Nathaniel
AU - Scuffham, James
AU - Sjögreen Gleisner, Katarina
AU - Tipping, Jill
AU - Wevrett, Jill
AU - Kayal, Gunjan
AU - Lassmann, Michael
N1 - Score=10
PY - 2021/7/23
Y1 - 2021/7/23
N2 - Purpose: Patient-specific dosimetry is required to ensure the safety of molecular radiotherapy and to predict response. Dosimetry involves several steps, the first of which is the determination of the activity of the radiopharmaceutical taken up by an organ/lesion over time. As uncertainties propagate along each of the subsequent steps (integration of the time–activity curve, absorbed dose calculation), establishing
a reliable activity quantification is essential. The MRTDosimetry project was a European initiative to bring together expertise in metrology and nuclear medicine research, with one main goal of standardizing quantitative 177Lu SPECT/CT imaging based on a calibration protocol developed and tested in a multicentre intercomparison. This study presents the setup and results of this comparison exercise.
Methods: The inter-comparison included nine SPECT/CT systems. Each site performed a set of three measurements with the same setup (system, acquisition and reconstruction): (1) Determination of an image calibration for conversion from counts to activity concentration (large cylinder phantom), (2) determination of recovery coefficients for partial volume correction (IEC NEMA PET body phantom with sphere inserts), (3) validation of the established quantitative imaging setup using a 3D printed two-organ phantom (ICRP110-based kidney and spleen). In contrast to previous efforts, traceability of the activity measurement was required for each participant, and all participants were asked to calculate uncertainties for their SPECT-based activities.
Results: Similar combinations of imaging system and reconstruction lead to similar image calibration factors. The activity ratio results of the anthropomorphic phantom
validation demonstrate significant harmonization of quantitative imaging performance between the sites with all sites falling within one standard deviation of the mean values for all inserts. Activity recovery was underestimated for total kidney, spleen, and kidney cortex, while it was overestimated for the medulla.
Conclusion: This international comparison exercise demonstrates that harmonization of quantitative SPECT/CT is feasible when following very specific instructions of a dedicated calibration protocol, as developed within the MRTDosimetry project. While quantitative imaging performance demonstrates significant harmonization, an over and underestimation of the activity recovery highlights the limitations of any partial
volume correction in the presence of spill-in and spill-out between two adjacent volumes of interests.
AB - Purpose: Patient-specific dosimetry is required to ensure the safety of molecular radiotherapy and to predict response. Dosimetry involves several steps, the first of which is the determination of the activity of the radiopharmaceutical taken up by an organ/lesion over time. As uncertainties propagate along each of the subsequent steps (integration of the time–activity curve, absorbed dose calculation), establishing
a reliable activity quantification is essential. The MRTDosimetry project was a European initiative to bring together expertise in metrology and nuclear medicine research, with one main goal of standardizing quantitative 177Lu SPECT/CT imaging based on a calibration protocol developed and tested in a multicentre intercomparison. This study presents the setup and results of this comparison exercise.
Methods: The inter-comparison included nine SPECT/CT systems. Each site performed a set of three measurements with the same setup (system, acquisition and reconstruction): (1) Determination of an image calibration for conversion from counts to activity concentration (large cylinder phantom), (2) determination of recovery coefficients for partial volume correction (IEC NEMA PET body phantom with sphere inserts), (3) validation of the established quantitative imaging setup using a 3D printed two-organ phantom (ICRP110-based kidney and spleen). In contrast to previous efforts, traceability of the activity measurement was required for each participant, and all participants were asked to calculate uncertainties for their SPECT-based activities.
Results: Similar combinations of imaging system and reconstruction lead to similar image calibration factors. The activity ratio results of the anthropomorphic phantom
validation demonstrate significant harmonization of quantitative imaging performance between the sites with all sites falling within one standard deviation of the mean values for all inserts. Activity recovery was underestimated for total kidney, spleen, and kidney cortex, while it was overestimated for the medulla.
Conclusion: This international comparison exercise demonstrates that harmonization of quantitative SPECT/CT is feasible when following very specific instructions of a dedicated calibration protocol, as developed within the MRTDosimetry project. While quantitative imaging performance demonstrates significant harmonization, an over and underestimation of the activity recovery highlights the limitations of any partial
volume correction in the presence of spill-in and spill-out between two adjacent volumes of interests.
KW - Quantitative SPECT/CT
KW - 177Lu SPECT/CT imaging
KW - Standardization of SPECT/CT imaging
KW - Harmonization of SPECT/CT imaging
KW - International multicenter comparison exercise
KW - Traceability of SPECT/CT imaging
KW - Molecular radiotherapy (MRT)
KW - 3D printing
KW - Phantom
UR - https://ecm.sckcen.be/OTCS/llisapi.dll/open/48015003
U2 - 10.1186/s40658-021-00397-0
DO - 10.1186/s40658-021-00397-0
M3 - Article
SN - 2197-7364
VL - 8
SP - 1
EP - 17
JO - EJNMMI Physics
JF - EJNMMI Physics
ER -