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dc.contributor.authorTran-Gia, J.
dc.contributor.authorRobinson, A. P.
dc.contributor.authorCalvert, Nicholas
dc.contributor.authorDenis-Bacelar, A. M.
dc.contributor.authorFenwick, A. J.
dc.contributor.authorFerreira, K. M.
dc.contributor.authorFinocchiaro, D.
dc.contributor.authorFioroni, F.
dc.contributor.authorGrassi, E.
dc.contributor.authorHeetun, W.
dc.contributor.authorJewitt, S. J.
dc.contributor.authorKalathas, T.
dc.contributor.authorKotzasarlidou, M.
dc.contributor.authorLjungberg, M.
dc.contributor.authorMcGowan, D. R.
dc.contributor.authorScuffham, J.
dc.contributor.authorGleisner, K. S.
dc.contributor.authorTipping, J.
dc.contributor.authorWevrett, J.
dc.contributor.authorLassmann, M.
dc.date.accessioned2021-01-06T11:15:20Z
dc.date.available2021-01-06T11:15:20Z
dc.date.issued2020en
dc.identifier.citationTran-Gia J, Robinson AP, Calvert N, Denis-Bacelar AM, Fenwick AJ, Ferreira KM, et al. An international quantitative SPECT/CT imaging exercise for Lu-177. European Journal of Nuclear Medicine and Molecular Imaging. 2020;47(SUPPL 1):S15-S6en
dc.identifier.urihttp://hdl.handle.net/10541/623607
dc.description.abstractAim/Introduction: Patient-specific dosimetry is required to ensure the safety of molecular radiotherapy treatments 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 standardising quantitative Lu-177 SPECT/CT imaging based on a calibration protocol developed and tested in a multicentre intercomparison. Materials and Methods: The intercomparison included eight SPECT/CT systems (3×Siemens, 4×GE, 1×Mediso). Each site performed three measurements using the same acquisition (medium energy collimator, 2×60 projections of 60s, 208keV main energy windows) and reconstruction (OSEM with 25 iterations, 2 subsets, no postfiltering, attenuation correction [CT-based], triple-energy-window scatter correction [6%- 20%-6% scatter-main-scatter], and resolution recovery [if available]): 1. Determination of image calibration factor (ICF): Counts (enlarged VOI around 216-mm Jaszczak cylinder filled with ~400MBq) divided by activity and scan duration (unit: cps/MBq). 2. Determination of recovery coefficients (RCs) for partial-volume correction (PVC) in IEC NEMA body phantom with 6 hot spheres (activity concentration ~2.0MBq/mL): Activity in CT-based VOI (counts/ICF/scan_duration) divided by each sphere’s activity. Recovery curve: Comparison of weighted 3-parameter (b1/(1+(b2/volume)^b3)) and 2-parameter fit (b1:=1) of RCs against sphere volumes. 3. Validation of quantitative imaging setup in 3D-printed kidney and spleen phantoms filled with different activity concentrations (kidney cortex & spleen: ~1.5 MBq/mL, kidney medulla: ~0.5 MBq/mL) assembled in Jaszczak cylinder (custom-made baseplate for repeatable positioning): Activity in CT-based VOI (counts/ICF/scan_duration) divided by volume-dependent recovery value. An uncertainty analysis was performed for all measurements. Results: Similar combinations of imaging system and reconstruction led to similar ICF values (Siemens 3/8”: [21.5±1.6] cps/MBq, GE 3/8”: [45.4±2.5] cps/MBq). In the anthropomorphic phantom validation, the mean ratios between SPECT-based and radionuclide calibrator-based activity were very close to the ideal value of 1 for the 3-parameter fit: 1.02±0.10 (kidney), 1.07±0.11 (spleen). Larger deviations were seen for the 2-parameter-fit: 0.89±0.06 (kidney), 0.94±0.06 (spleen). Conclusion: This comparison exercise shows that reliable quantitative SPECT/CT is feasible when following the very specific recommendations of the dedicated calibration protocol developed within MRTDosimetry. In addition, for an anthropomorphic phantom, the count loss due to spill-out was successfully compensated by using a standardized PVC based on sphere-based RCs.en
dc.language.isoenen
dc.titleAn international quantitative SPECT/CT imaging exercise for Lu-177en
dc.typeMeetings and Proceedingsen
dc.contributor.departmentDepartment of Nuclear Medicine, University of Würzburg, Würzburg, GERMANYen
dc.identifier.journalEuropean Journal of Nuclear Medicine and Molecular Imagingen
dc.description.noteen]


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