ICRP publications on medical exposures: Digital radiology

Abstract

ICRP has published several documents dealing with medical exposures; one of them addresses digital radiology. All these documents are expected to help medical practitioners and medical physicists to improve radiation safety. It is also expected that regulators, administrators and industry take into consideration the content of these publications. ICRP-93 (Managing patient dose in digital radiology, 2004) emphasizes that diagnostic information provided by digital detectors can be equal or superior to conventional film-screen systems, with comparable patient doses. With digital systems, an overexposure can occur without an adverse impact on image quality. A tendency to increase doses can occur. The ICRP publication includes several formal recommendations dealing with: training aspects; review of diagnostic reference levels (DRL); patient dose audits; availability of the original image data to the user; optimization when new digital systems or new postprocessing software are introduced; procedures for quality control; justification criteria, and role of the industry. It is expected that the ICRP report will help to profit from the benefits of this important technological advance in medical imaging with the best management of radiation doses to the patients. It should also promote training actions before the digital techniques are introduced in radiology departments and encourage the industry to offer enough technical and dosimetric information to radiologists, radiographers and medical physicists to help in image optimization. Some experimental results of the impact of the ICRP recommendations on this topic, using a database with 204,000 dose values for projection radiography, are presented. Median values of patient entrance doses increased 40% to 110% after computed radiography implementation, compared to earlier values with screen-film. Increases were corrected after focused training actions and on line patient dose audits. At present, doses have been substantially reduced; they range between 13% and 38% of the European DRL established for screen-film radiography.