UNLABELLED: Misalignment between transmission and emission scans in attenuation-corrected (AC) cardiac SPECT can introduce errors of measured activity. The severity of these errors, however, has not yet been fully elucidated. METHODS: We performed a phantom measurement as well as a study of patients with low likelihood of coronary artery disease. Transmission and emission scans were acquired using a triple-head SPECT system with a collimated 241Am line source and an offset fanbeam collimator. The left ventricular myocardium was divided into five segments, and the mean regional activity was calculated for each segment using a semiquantitative polar map approach. Misalignment between transmission and emission data was created by shifting the emission data along the x, y or z axis. RESULTS: In the heart phantom, a shift between the transmission and emission data produced a decrease or increase in relative regional activity in each segment resulting in heterogeneous activity distribution. A 7-mm (1-pixel) shift produced up to 15% change in relative regional activity, suggesting that even a small misalignment between transmission and emission data can produce serious errors in measured activity. In the clinical data, the effects of misalignment were less significant than those observed in the phantom data but were still measurable and visually identifiable. CONCLUSION: The results indicate that a small misalignment between the transmission and emission data can produce serious errors in measured activity, and, thus, geometrical precision is essential for accurate diagnosis of AC SPECT images.
UNLABELLED: Misalignment between transmission and emission scans in attenuation-corrected (AC) cardiac SPECT can introduce errors of measured activity. The severity of these errors, however, has not yet been fully elucidated. METHODS: We performed a phantom measurement as well as a study of patients with low likelihood of coronary artery disease. Transmission and emission scans were acquired using a triple-head SPECT system with a collimated 241Am line source and an offset fanbeam collimator. The left ventricular myocardium was divided into five segments, and the mean regional activity was calculated for each segment using a semiquantitative polar map approach. Misalignment between transmission and emission data was created by shifting the emission data along the x, y or z axis. RESULTS: In the heart phantom, a shift between the transmission and emission data produced a decrease or increase in relative regional activity in each segment resulting in heterogeneous activity distribution. A 7-mm (1-pixel) shift produced up to 15% change in relative regional activity, suggesting that even a small misalignment between transmission and emission data can produce serious errors in measured activity. In the clinical data, the effects of misalignment were less significant than those observed in the phantom data but were still measurable and visually identifiable. CONCLUSION: The results indicate that a small misalignment between the transmission and emission data can produce serious errors in measured activity, and, thus, geometrical precision is essential for accurate diagnosis of AC SPECT images.
Authors: Ji Chen; Serpil F Caputlu-Wilson; Hongcheng Shi; James R Galt; Tracy L Faber; Ernest V Garcia Journal: J Nucl Cardiol Date: 2006 Jan-Feb Impact factor: 5.952
Authors: Michael Souvatzoglou; Frank Bengel; Raymonde Busch; Coletta Kruschke; Helga Fernolendt; Denise Lee; Markus Schwaiger; Stephan G Nekolla Journal: Eur J Nucl Med Mol Imaging Date: 2007-07-28 Impact factor: 9.236
Authors: Michael A King; Joyoni Dey; Karen Johnson; Paul Dasari; Joyeeta M Mukherjee; Joseph E McNamara; Arda Konik; Cliff Lindsay; Shaokuan Zheng; Dennis Coughlin Journal: Med Phys Date: 2013-11 Impact factor: 4.071
Authors: Alexander G Pitman; Victor Kalff; Bruce Van Every; Borghild Risa; Leighton R Barnden; Michael J Kelly Journal: J Nucl Cardiol Date: 2005 Jul-Aug Impact factor: 5.952