A study on the dependence of the change in total scan time on the timing of the scan-time determination

This study examined the change in the scan time according to the scan-time determination in an examination by using a pre-set time to identify a reasonable alternative to altering the scan time. A hepatobiliary scan was conducted using the radiopharmaceutical 99 m Tc-mebrofenin in the Nuclear Medicine Department of Asan Medical Center from January to March 2012. Scanning began five minutes after an intravenous injection of 222 MBq (megabecquere) (6 mCi). As two detectors were placed facing each other, the patient was asked to stand between the two detectors with the front of the abdomen pressed as close as possible against the detector. After scanning, the measurement was carried out to determine the expected end time of scanning when the scan time was 10, 25, 50, and 75% of the total scan time. After scanning had been completed, the measurement time was compared with the final scan time and the expected scan time in the middle of scanning. A phantom was also used to examine the dependence of the change in time on the dose. The difference was examined when the scan time was 10, 25, 50, and 75% of the total expected scan time after beginning the scan. According to the study results, the difference was five seconds or more at the maximum when the scan time was 10% of the total expected scan time. The difference was significant when the scan time was 25% or 50% of the total expected scan time.