Slip ring SPECT dynamic data acquisition with one second time activity curve reconstruction

467 Objectives The GE Infinia SPECT scanner employs a slip ring gantry enabling acquisition of a continuous data set over the entire 360 degree rotation. Serial image reconstruction can be performed from every acquisition step up to a smallest time resolution of 1 second. The resolution and accuracy of time activity curves (TAC) generated with this new method (NM) were compared to the conventional method (CM). Methods Dynamic data acquisition was performed with a dual gamma camera SPECT scanner (GE Infinia3). Continuous SPECT data was acquired at 120steps/rotation/minute. In a phantom study, 30MBq of Tc-99m was infused twice into water (3L) in a cylindrical phantom by slow bolus injection (10 seconds) during a 6 min dynamic scan. TAC of the phantom was compared to an ideal curve. In a human study, 740MBq of Tc-99m HSAD was injected over 1 minute and a dynamic SPECT scan of heart and upper abdomen of the subject was performed for 10 minutes. TACs were calculated using ROIs placed on the left ventricle and liver and were compared to the TACs measured using the conventional method which generated a single data point per rotation. Results The phantom study NM TAC showed good linearity and response especially in the region of rapid activity change. Dispersion, attributed to the rotation time (1 min), was observed in the NM TAC, however, the temporal resolution (1 data point per second) of the NM TAC was found to be superior to that of the coarse CM TAC plot (1 data point per minute). TACs of left ventricle and liver using the new and conventional methods are shown in Figure1 (blue:LV, yellow:liver). Unlike the conventional method, the new method was able to detect the TAC peak. Conclusions The new slip ring dynamic data acquisition method enables activity to be measured with a time resolution down to 1 second and is thus expected to improve the quantitative accuracy of SPECT ligand kinetic analysis