2016 年 2 巻 p. 50-56
An effective dose was sometimes detected by the personal dosimeter (glass badge) worn by the radiological technologist in an ultrasound examination. The maximum effective dose detected was 0.2 mSv per month and 1.1 mSv per year. An investigation suggested that the source of the radiation exposure was the administration of radiopharmaceuticals before ultrasound examination. We evaluated 921 cases in which radiopharmaceuticals had been administered before an ultrasound examination between April 2010 and March 2012. The effective dose was higher when more ultrasound examinations were carried out subsequent to the administration of radiopharmaceuticals. The shielding ratio for a 4-mm lead sheet was approximately 95% for Tc-99m and approximately 79% for I-131, suggesting that a lead sheet (masking shield) may be effective.
