A Study on the Dose Distribution from Upper GI-Tract X-ray Examination as a Mass Screening and Its Optimization

Abstract

In Japan, upper GI-tract X-ray examinations are widely conducted as mass screenings. From the view-point of radiation protection, justification for the examination and optimization of radiation protection have been performed but not adequately, because various factors are related with the dose estimates. In previous studies, it was reported that the time of fluoroscopy varied greatly with medical facilities and radiation technicians. In order to obtain a basic information on the dose distribution, we investigated the time of fluoros-copy, the number of exposures and other data on the upper GI-tract X-ray examination. The number of subjects was 397, aged from 19 to 80. The average time of fluoroscopy for each radiological technician was 32 to 319 seconds. The average time of fluoroscopy per exposure was 4.6 to 19 secons, and mainly depended both on the facility and on the type, fluorography or radiography. The number of exposures varied between 7 and 24, not only according to the facility but also with the radiological technician. From these results, it was evident that optimization in upper GI-tract examination depended on the technical control of a radiological technician. This study suggested that it is necessary to take the dose distribution into account for the purpose of doing risk-benefit analysis of the upper GI-tract X-ray examination conducted as a mass screening.