I. Variations in the Radiation Dose received by the Patient in Diagnostic Radiology

Abstract

One of the most striking facts revealed by the National Survey of Diagnostic Radiology sponsored by the Adrian Committee (Ministry of Health, 1960) has been the wide variation in dose received by the patient for a given type of examination. This may partly be explained by the fact that patients come in different shapes and sizes, and that a given part of the body may be examined by a wide variety of techniques all of which may be classed as the same type of examination. In the National Survey, the dose to the incident skin surface was derived for each of the 5,414 examinations reported, and frequency distributions can therefore be made. Figure 1 gives the distribution of skin dose for one class of examination, namely, the 206 adult males subjected to a barium meal examination. Skin doses during the examination varied between 2 r and over 100 r, with a mean of 22 r, but it does not follow that the whole of the dose was necessarily given to one area of skin. The highest dose was made up of fluoroscopy for three minutes at a dose-rate of 23 r/minute, and six radiographs at 5·5 r per film, giving a total of 103 r; a fairly high kilovoltage and high milliamperage were used, combined with very low filtration, but the field sizes were so small that the measured gonad dose was only 2·1 mr for the whole examination.