Basic Evaluation of Standardized Uptake Value Using SPECT Single Unit to Compare with Specific Binding Ratio in Dopamine Transporter Scintigraphy

Abstract

Specific binding ratio (SBR) is mainly used as a quantitative index of dopamine transporter scintigraphy, nevertheless, the striatal volume which is influenced by individual differences and aging is calculated as a fixed value. Therefore, standardized uptake value (SUV) calculated with single photon emission computed tomography (SPECT) single unit was compared with SBR. A cylinder phantom filled with Iodine-123 was measured and the calibration factor (CF) was calculated from the count rate per volume. The conditions that SBR calculated using the striatal phantom and the radioactivity concentration calibrated and calculated by CF approximate the actual measured value were determined. There was a strong positive correlation between SBR and SUV with 16 clinical cases in Pearson's correlation coefficient (r>0.7). Moreover, a statistical analysis between the normal and diseased groups for SBR and SUV showed a significant difference (p<0.05). The area under the receiver operating characteristic curve (AUC) of SUV was 0.875, which was useful for clinical diagnosis; however, SBR had a higher diagnostic accuracy. SBR is considered to be suitable for quantitative analysis with SPECT single unit.