Radiation doses and detriment from chest x-ray examinations

Radiation dose distributions for chest x-ray examinations have been measured in a Rando phantom for three views (AP, PA and lateral) as a function of kVp. On the basis of these data, the relationship between the surface dose, energy imparted and the effective dose equivalent have been determined. The mean energy imparted in a typical chest examination (PA + lateral views at 100 kVp) is 1.7 mJ and the corresponding value of the effective dose equivalent, HE, is 42 muSv. The measured radiation doses associated with chest x-rays were compared with the predictions of Monte Carlo calculations. The average difference between Monte Carlo and measured data for the HE was only about 16%. Demographic features (age/sex) of patients undergoing chest x-rays were investigated, and a population irradiation factor (PIF) introduced to estimate the radiation detriment to this population. The probability of expressed radiation-induced detriment to the patient population from chest x-ray examinations was computed to be about one half of that expected for a normal adult (working) population receiving the same dose. The radiation risk associated with chest x-ray examinations for this population was estimated to be less than 0.3 fatal cancers plus serious genetic disorders in the first two generations per million patient examinations.