Evaluation of Spatial Resolution Variability in Whole Body Bone Scans
Presentations
PO-GePV-I-19 (Sunday, 7/25/2021) [Eastern Time (GMT-4)]
Purpose: To assess the variability in spatial resolution observed in whole body bone scans completed on different scintillation camera imaging devices within the same facility as reported by clinical staff.
Methods: Upon installation of new scintillation camera, clinical staff reported variability in spatial resolution among cameras of same model and detector specifications when performing whole body bone scans. Static intrinsic and extrinsic spatial resolution FWHM measurements obtained with a four-quadrant bar phantom during annual/acceptance testing of the units were compared. The clinical whole body bone scan was replicated with two capillary line sources containing ⁹⁹ᵐTc spaced 20 cm apart and perpendicular to the direction of table travel. Detector contouring was active and automatically adjusted the position of each detector relative to the line sources. Distances from the lines sources to the camera heads were measured for all acquisitions. Static acquisitions of the line sources was obtained at same distance as measured above.
Results: Comparison of static intrinsic and extrinsic FWHM measurements among the cameras showed minor variation. Significant variation in FWHM measurements of line sources between imaging devices was observed. The cause of variation was determined to be variability in the default table height position settings which resulted in variation in collimator-to-source distances on each imaging device. Default table height was set by the service engineer at the time of installation of each unit and was not standardized across the camera systems. The default table height setting was standardized and measurements were repeated.
Conclusion: Variability in default table height settings for whole body bone scans resulted in reduced and inconsistent spatial resolution in clinical studies among imaging devices. Recommend routine verification of table height settings during whole body bone scans and inter-comparison of QC data to ensure optimum image quality during clinical scans.
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Taxonomy
IM- Nuclear Medicine General: Quality Control and Image Quality Assessment
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