[Mammography: consideration about radiation from the point of a radiologist's view]

Mammography is becoming popular rapidly in Japan because it is now admitted as a modality for breast screening. Radiation will not cause any adverse effect if mammography screening is done for women over 50 years old, every other year and by only MLO (medio-lateral oblique) view as this is recommended by the government. Radiation for one view is regulated to be less than 3mGy. Radiation by mammography may become problem if it is done for younger women, by more views (i.e. cranio-caudal, other additional views) and more often especially for follow up. Radiation may be more if the system is not adequate. In Japan mammograms are read by surgeons in many institutions and there are not enough medical physicists in each hospital. Cooperation between medical physicists, radiographers and radiologists will be necessary to achieve good quality mammography with adequate radiation.