Analysis by V. Matarese
Over the past decade, the radiology community has become increasingly concerned about the population’s exposure to ionizing radiation from medical sources. In Europe, these concerns are evidenced by projects such as the European Medical ALARA Network (www.eman-network.eu) and by documents such as the European Society of Radiology’s white paper on radiation protection . Computed tomography is receiving the greatest attention, as this imaging modality is the single greatest source of medical radiation today, due both to its wide clinical use and relatively high radiation dose per examination [2, 3].
In the interest of preserving the great diagnostic advances permitted by CT, while simultaneously safeguarding patients from the damaging effects of ionizing radiation, numerous approaches to reducing radiation exposure have been proposed. These approaches range widely and work at different levels, starting with the requirement for greater clinical justification for any CT examination and the use, whenever possible, of alternative diagnostic means. Practical approaches to reducing radiation dose rely on accurate patient positioning in the scanner and precise choice of scanning range so that only the region of interest is irradiated. Technological approaches include the optimization of scanning parameters for both the clinical question and the patient’s morphological characteristics as well as the implementation of sophisticated dose-reducing hardware devices and software algorithms. How to choose among these different dose-reducing strategies and use them in combination without sacrificing image quality is a current topic of discussion. Recent advice for particular clinical applications has been offered by medical associations such as the Society of Pediatric Radiology with its series of “ALARA CT” conferences  and the Society of Cardiovascular Computed Tomography which recently published dose optimization guidelines . Still, the challenge of putting theory into practice remains, especially for community radiologists working outside of the academic setting.