The exp o s ure on the mass examination of chest photofluorography of pupils and teachers in Osaka City was surveyed. The mass examination of the chest has been carried out at the time of the entry into the primary school(6 years old) and the junior high school(12 years old) for pupils and annually for teachers in Osaka Ciry.
One primary school and one junior high school were picked up. The exposur e s of ten pupils and ten teachers sgthpled randomly in each school were measured with a thermoluminescence dosimeter. The average exposure at the back skin was 70.6±30.7 mR for the 6 years old pupils,85.6±21.0 mR for 12 years old pupils and 131.5±43.7 mR for the teachers.
The International Commission on Radiation Protection (ICRP) has assigned a limit that the dose equivalent in the chest X-ray mass examination is preferable less than 1 mGy. However, this survey shows that the aim of the ICRP is not satisfied even in pupils of 6 years old. To reduce the population dose, it is necessary to reconsider how to carry out X-ray mass examinations which have been used.
