Exposure characteristics of diagnostic X-ray machines

Results of exposure and quality measurements carried out on 199 diagnostic X-ray installations are presented. In addition, the exposures that would be incident on the entrance surface of patients undergoing upright postero-anterior chest radiography are reported for 108 of these installations, and the exposure rates at the fluoroscope panel under conditions employed for normal gastric fluoroscopy are reported for 37 of them. A spread in radiographic exposure rates and exposure rates at the fluoroscope panel of as much as by a factor of 5 is indicated when the units are operated under similar conditions. The variation in patient exposure is even greater for chest radiography. The HVTs for practically all of the units are reported as being between 2·0 and 4·0 mm Al.