A comparison of radiation dose in examination of the abdomen using different radiological imaging techniques.

Typical radiation doses for abdominal examinations were determined for field sizes and entrance doses commonly selected on image intensifier based digital radiographic systems. In addition, measurements were also performed using conventional film-screen methods, a 100 mm camera combination and a phosphor storage computed radiography system. Both antero-posterior and postero-anterior projections were assessed. An anthropomorphic phantom loaded with lithium fluoride thermoluminescent dosimeters was used to measure entrance surface doses. Organ equivalent doses, deduced using normalized organ dose data, were used to calculate effective dose and effective dose equivalent. A comparison of the imaging techniques on the basis of effective dose indicated that significant dose reductions (by approximately a factor of 3) may be expected if the abdomen is imaged using a postero-anterior rather than an antero-posterior projection for a given imaging system. If digital imaging systems are used instead of a conventional film-screen technique, patient effective dose for a given projection can be lower by at least a factor of 5.