【Objective】In order to estimate the radiation exposure doses to the examiner from the videofluoroscopic examination of swallowing, we conducted a dosimetric study by means of a man-shaped phantom and dosimeters.

【Methods】Simulating the lateral view examination setting, x-rays were emitted to the phantom and the radiation doses were measured at 32 locations with an ionization chamber type dosimeter. The radiation doses in the anterior-posterior view examination setting were also measured at one location. Measurements were also carried out in the settings where radiation protection devices were employed. In addition, the radiation dose to the examiner's hand placed in the x-ray field was estimated using thermoluminescent dosimeters attached to the surface of the phantom.

【Results】The effective dose rates to the examiner in the lateral view examination were 414 μSv/h when the dosimeter was placed 50 cm away from the phantom and 28.4 μSv/h when it was placed 200 cm away from the phantom. The dose rate in the anterior-posterior view examination was about 1.5 times as high as that in the lateral view examination. When a radiation protective apron and a radiation protective screen were used, the doses were reduced to one fifth and one thirty-sixth, respectively. The dose rate to the examiner's hand was approximately 54 μSv/sec.

【Discussion】Assuming that the average duration of radiation exposure for one examination is 5 minutes, the annual radiation exposure dose to the examiner would not exceed the legal dose limit for occupational radiation exposure, and in most cases, that for the general public. It is also suggested that the dose would be lower than the differences in natural environmental radiation exposure doses between various areas in the world and than the occupational radiation exposure dose to aircraft crew. However, it should be emphasized that it is essential to make every effort to minimize radiation exposure by, for example, utilizing radiation protective devices.