An anthropomorphic phantom study of brain dopamine transporter SPECT images obtained using different SPECT/CT devices...

The aim of this study was to evaluate differences in dopamine transporter SPECT images among different SPECT/CT devices and to determine the most appropriate region of interest (ROI) for semiquantitative evaluation.

An anthropomorphic striatal phantom was filled with (123)I solutions of different striatum-to-background radioactivity ratios. Data were acquired using 2 SPECT/CT devices equipped with low- to medium-energy general-purpose and low-energy high-resolution (LEHR) collimators. The SPECT images were reconstructed by filtered backprojection with both attenuation and scatter correction and then were analyzed using specific binding ratio (SBR). The most appropriate of 7 ROI types was determined, and we then compared the linearity and recovery of SBR among the different SPECT/CT devices and collimators.

The linearity of SBR was excellent for all types of ROIs. The ROI contouring the striatum based on the CT images showed the best recovery of SBR using mean activity in the striatal ROI (SBRmean) (47.8%). For this ROI, the recovery of SBRmean for SPECT/CT with a LEHR collimator with thick septa and a long hole length was 61.6%-significantly higher than that of other devices.

The ROI contouring the striatum based on CT images was considered appropriate for evaluating dopamine transporter SPECT/CT. Among the different SPECT/CT devices, an LEHR collimator designed for (123I)I imaging is recommended.