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dc.contributor.authorTran-Gia, J.
dc.contributor.authorRobinson, A. P.
dc.contributor.authorBobin, C.
dc.contributor.authorCalvert, Nicholas
dc.contributor.authorCollins, S.
dc.contributor.authorDenis-Bacelar, A. M.
dc.contributor.authorFenwick, A.
dc.contributor.authorFerreira, K.
dc.contributor.authorFinocchiaro, D.
dc.contributor.authorFioroni, F.
dc.contributor.authorGianopoulou, K.
dc.contributor.authorGrassi, E.
dc.contributor.authorHeetun, W.
dc.contributor.authorJewitt, S. J.
dc.contributor.authorKotzasarlidou, M.
dc.contributor.authorLjungberg, M.
dc.contributor.authorLourenco, V.
dc.contributor.authorMcGowan, D. R.
dc.contributor.authorScuffham, J.
dc.contributor.authorGleisner, K. S.
dc.contributor.authorSolc, J.
dc.contributor.authorThiam, C.
dc.contributor.authorTipping, Jill
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, Bobin C, Calvert N, Collins S, Denis-Bacelar AM, et al. An international quantitative SPECT/CT imaging exercise for assessment of Ba-133 as surrogate for I-131. European Journal of Nuclear Medicine and Molecular Imaging. 2020;47(SUPPL 1):S448-S9en
dc.identifier.urihttp://hdl.handle.net/10541/623606
dc.description.abstractAim/Introduction: In nuclear medicine imaging, commissioning and quality control are typically performed based on hollow containers manually filled with radionuclide solutions. Most associated sources of uncertainty (e.g., filling volume, activity concentration) can be overcome by sealed, long-lived surrogate sources containing a radionuclide of comparable energies and emission probabilities, traceable to a primary standard. This study presents the results of a quantitative SPECT/ CT imaging comparison exercise performed within the MRTDosimetry project to assess the applicability of Ba-133 sources as a surrogate for I-131 and to determine a crosscalibration factor. Materials and Methods: Cylinders of four different dimensions (active volumes of diameters 7.5, 15, 30, and 60 mm and 38 mm height, resulting in volumes of 1.68, 6.72, 26.9 and 107.4 cm3) and two different caps (one for complete closure, one with filling hole) were fabricated with a stereolithography 3D printing system (Formlabs Form 2, Tough resin). Optimal source placement in 216-mm Jaszczak cylinder was ensured by a laser-cut attachment baseplate designed based on simulations of spilled-out counts (Gaussian convolution with 20-mm FWHM). Solid Ba-133 surrogate sources were produced at two metrology institutions: CEA (activity concentration [206.2±5.8] kBq. mL−1) and CMI ([99.8±1.6] kBq.mL−1), with leakage and contamination tests according to ISO9978. The comparison exercise included eight SPECT/CT systems (3×Siemens, 5×GE). Each site had to perform three measurements with different sources attached in a water-filled Jaszczak cylinder: 1) Ba-133 CEA sources, 2) Ba-133 CMI sources, 3) identical containers filled with liquid I-131. Parameters: High-energy collimator, 2×60 projections of 30s, Ba-133: 356.0keV [5%- 15%-10% scatter-main-scatter], I-131: 364.5keV [6%-20%- 6%], low-dose CT, OSEM with standard corrections. A CTbased VOI analysis was carried out to compare differences in pseudo-ICF (image calibration factor including partialvolume related errors: counts in VOI per activity and scan duration). A regression analysis was performed to determine a cross-calibration factor. Results: Iodine-131 pseudo-ICFs were higher than Ba-133 pseudo-ICFs for all reconstructions and systems. Equivalent setups (camera and reconstruction) yielded comparable pseudo-ICFs (average relative error 5.6% between three equivalent GE setups). The regression analysis resulted in a cross-calibration factor of 0.70±0.02. This value is in agreement with the ratio 0.764±0.005 of the emission probabilities (62.05±0.19)% (Ba-133) and (81.2±0.5)% (I-131) [1]. Conclusion: Although this international comparison exercise was challenging due to varying transport regulations between countries, we could show that traceable solid Ba-133 sources can be used as surrogate for liquid I-131, thus potentially reducing inherent problems with on-site activity measurement and phantom preparation.en
dc.language.isoenen
dc.titleAn international quantitative SPECT/CT imaging exercise for assessment of Ba-133 as surrogate for I-131en
dc.typeMeetings and Proceedingsen
dc.contributor.departmentDepartment of Nuclear Medicine, University of Würzburg, Würzburg, GERMANY,en
dc.identifier.journalEuropean Journal of Nuclear Medicine and Molecular Imagingen
dc.description.noteen]


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