Abstract
Imaging start time of single-photon emission computed tomography (SPECT) scan is recommended between 3 hours and 6 hours after injection of 123I-ioflupane in Ioflupane clinical practice guidelines. But image includes the effect of physiological actions of the human body and the attenuation at 13.27 hours physical half-life of 123I. Therefore, we evaluated the effect of the image by the elapsed time of imaging start time. Optimal cut-off frequency of Butterworth filter were examined phantom by normalized mean square error. Count was reduced by 23.1% in 5 hours, but cut-off frequency of Butterworth filter was 0.11 cycle/pixel in 0-5 hours from phantom data. Ten subjects (age 55-85 years) were injected with 123I-ioflupane of 110-199 MBq into the vein only once. And we examined the specific binding ratio (SBR) in inspection of injection after 5. 5 hours and 3hours. Decrease of counts value increased the coefficient of variance (CV) between 3hours and 5.5 hours after injection, but the improvement of statistical noise by pre-processing filter reduced the CV. No significant difference in the result of SBR was found between 3hours and 5. 5 hours after injection. Our results suggest that imaging start time of SPECT scan is recommended between 3hours and 5.5 hours after injection of 123I-ioflupane.
