Radiation dosimetry survey of computed tomography systems from ten manufacturers

Profiles of the absorbed dose delivered throughout cylindrical and anthropomorphic phantoms during single scans by computed tomography systems from ten manufacturers were measured using LiF thermoluminescent dosemeters (TLD) and X-ray therapy verification film. The dose profiles demonstrate that a significant portion of the dose is delivered outside the imaged volume of a single scan. The doses measured in cylindrical Plexiglas phantoms were similar to those measured in anthropomorphic cross sections of tissue substitute materials except near the centre of the thorax section. The film results, obtained using a single calibration curve, agreed with the TLD results to within 25% for most systems.