J Radiol
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Reducing radiation dose while maintaining adequate image quality on conventional and digital radiographs requires optimal use of the unit. Additional filtration avoids unnecessary tissue exposure and improves photon transmission. Automatic exposure control may reduce exposure and dose. ⋯ Radiographic films combined to rare-earth screens also afford a good photon-conversion efficiency. Large area flat panel amorphous silicon x-ray sensors may also reduce dose up to 50% compared to films. Finally, calculation of the Kerma-area product independent of the source distance constitutes an important indicator of radiation dose.
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After a risk analysis has been completed by the radiation safety officer, all entities where a source of ionizing radiation is present must established a monitored or controlled zone containing the source. When exposure exceeds the maximum regulatory dose, a dedicated color-coded controlled (yellow or orange) or restricted zone must be established. All assessments performed by the RSO should reflect normal working conditions. ⋯ The workers should undergo medical and dosimetric follow-up with the use of passive dosimetry. The use of operational dosimetry should be added when working in a controlled zone. A radiation dosimetry report for each worker should be available to the occupational medicine provider to ensure appropriate dosimetric monitoring.
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The effects of exposure to ionizing radiation are determined by the absorbed dose D. The equivalent dose H takes into consideration the variation in probability of a stochastic effect (cancer, leukemia, genetic mutation) based on the quality of the exposure. The effective dose E takes into account the sensitivity of tissues (T) to stochastic effects from radiation exposure. Optimization of radiation exposure to patients in diagnostic radiology in based on diagnostic reference levels (DRL): entrance surface dose or dose-area product for conventional radiology; CT dose index and DLP for CT.