Abstract
BackgroundHeart sizes vary greatly across the spectrum of patients referred for myocardial perfusion imaging. We therefore performed a phantom study to explore under controlled circumstances how count rates change when different volumes containing the same amount of activity are scanned. Two dedicated cadmium-zinc-telluride cameras, the D-SPECT (Spectrum Dynamics, Caesarea, Israel) and Discovery 530c (D530c, GE Healthcare, Haifa, Israel), and the conventional SPECT Anger (A-SPECT, GE Healthcare, Haifa, Israel) camera are included in the study.MethodsDifferent heart sizes were represented by syringes of various column heights mimicking a range of cardiac diameters. Syringes with fixed activity were scanned at five different volumes by successively adding non-radioactive water to the syringes. This procedure was repeated five times on each of the three cameras. Raw count rates were recorded for each scan to determine whether count rates changed with syringe column height.ResultsUsing mixed-effect regression modeling, a linear relationship was found between count rate and water column height. For the D-SPECT, D530c, and A-SPECT, the changes in count rate for each centimeter increase in water column height were −1.75, +0.28, and −0.022 kilocounts per min per MBq, respectively (95% confidence intervals −1.89 to −1.61, 0.19 to 0.36, and −0.035 to −0.009); all effects are significantly different from each other and significantly different from zero. Average coefficients of variation were 0.080, 0.028, and 0.009.ConclusionsThe D-SPECT demonstrated a significant progressive increase in count rate related to decreasing size of the imaged object. D530c count rate increased slightly with increasing column height. The Anger SPECT showed minimally increased count rates with decreasing column height, an order of magnitude smaller than the D-SPECT based on their relative coefficients of variation.Electronic supplementary materialThe online version of this article (doi:10.1186/s40658-014-0097-5) contains supplementary material, which is available to authorized users.
Highlights
Heart sizes vary greatly across the spectrum of patients referred for myocardial perfusion imaging
Instrumentation This study involved the use of a the D-SPECT camera at the Scarborough Cardiac Diagnostic Center (SCDC) and a Discovery 530c (D530c) camera at Etobicoke General Hospital (EGH)
The D-SPECT requires a brief pre-scan following which the technologist draws a region of interest (ROI) to define the left ventricular (LV) for cardio-centric detector column (DC) movements [9]
Summary
Heart sizes vary greatly across the spectrum of patients referred for myocardial perfusion imaging. Two dedicated cadmium-zinc-telluride cameras, the D-SPECT (Spectrum Dynamics, Caesarea, Israel) and Discovery 530c (D530c, GE Healthcare, Haifa, Israel), and the conventional SPECT Anger (A-SPECT, GE Healthcare, Haifa, Israel) camera are included in the study. Two direct-conversion cadmiumzinc-telluride (CZT) detector cameras have become available: the D-SPECT (Spectrum Dynamics, Caesarea Israel) and Discovery 530c (D530c, GE Healthcare, Haifa, Israel). These have several advantages over scintillation gamma-cameras, including much faster scans [6]. The population undergoing myocardial perfusion scans includes normal women, which extends this range downward. The scanned population includes a significant number of obese, diabetic, hypertensive, and ischemic patients at risk for left ventricular (LV) dilation, which extends the range upwards
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