Radiation Protection in Diagnostic Radiology

This paper summarizes technological advances in diagnostic radiography, fluoroscopy and computed tomography, mainly the developments in digital detectors and helical CT scanners with multiple-row detectors. It reviews dosimetric concepts and presents the most up-to-date information on the global patterns of use of radiological modalities as well as the trends in diagnostic medical exposure doses world-wide. Given the increase in population dose, and following the recent recommendations of the International Commission on Radiological Protection, emphasis is placed on the justification of the radiological procedures and the need for referring physicians to consult referral criteria. Protection is optimized by the radiation dose being commensurate with the purpose of the examination. The trade-offs between dose, noise, contrast and resolution are mentioned. The need to establish diagnostic reference levels as an optimization tool and the caveats in comparing some published numerical values are indicated. Methods of dose reduction involving equipment and software design, operational parameters and shielding calculations are discussed, and illustrative numerical examples are given.