The objectives of this paper were calculation and comparison of the effective doses, the risks of exposure-induced cancer, and dose reduction in the gonads for male and female patients in different projections of some X-ray examinations. Radiographies of lumbar spine [in the eight projections of anteroposterior (AP), posteroanterior (PA), right lateral (RLAT), left lateral (LLAT), right anterior-posterior oblique (RAO), left anterior-posterior oblique (LAO), right posterior-anterior oblique (RPO), and left posterior-anterior oblique (LPO)], abdomen (in the two projections of AP and PA), and pelvis (in the two projections of AP and PA) were investigated. A solid-state dosimeter was used for the measuring of the entrance skin exposure. A Monte Carlo program was used for calculation of effective doses, the risks of radiation-induced cancer, and doses to the gonads related to the different projections. Results of this study showed that PA projection of abdomen, lumbar spine, and pelvis radiographies caused 50%-57% lower effective doses than AP projection and 50%-60% reduction in radiation risks. Also use of LAO projection of lumbar spine X-ray examination caused 53% lower effective dose than RPO projection and 56% and 63% reduction in radiation risk for male and female, respectively, and RAO projection caused 28% lower effective dose than LPO projection and 52% and 39% reduction in radiation risk for males and females, respectively. About dose reduction in the gonads, using of the PA position rather than AP in the radiographies of the abdomen, lumbar spine, and pelvis can result in reduction of the ovaries doses in women, 38%, 31%, and 25%, respectively and reduction of the testicles doses in males, 76%, 86%, and 94%, respectively. Also for oblique projections of lumbar spine X-ray examination, with employment of LAO rather than RPO and also RAO rather than LPO, demonstrated 22% and 13% reductions to the ovaries doses and 66% and 54% reductions in the testicles doses, respectively.

-Increasing concern has been expressed in the literature that the knowledge of physicians regarding the radiation risk values incurred during different radiological examinations is inadequate. This study determined the amount of organ doses and the radiation risks involved in pediatric radiology in terms of the age and sex of patients. The X-ray examinations of the chest, abdomen, pelvis and skull in patients of six age groups (newborn, 1-, 5-, 10-and 15-year-old, and adult) were investigated. Exposure data of 480 patients were collected from four radiology departments and then Entrance Skin Exposure (ESE) values for standard patients in the six age groups as well as five X-ray examinations were measured. By using these practical data, the risk of exposure-induced cancer death (REID) values were estimated based on the risk models of the BEIR VII committee. It was shown that the differences in REID values in male and female patients were statistically significant for the chest and pelvis X-ray examinations. The X-rays of the abdomen, chest and pelvis have the highest REID values in 15-, 10-and 15-year-old patients, respectively. The results obtained can help physicians to make suitable decisions about the execution and justification of every X-ray examination in the different age groups. This information will help to prevent either overestimation or underestimation of radiation risks.

Background: Radia on doses associated with the conven onal dental radiographies are rela vely low, but their number is high. Therefore, jus fica on is necessary to ensure that radia on doses to pa ents, par cularly children, are kept as low as reasonably achievable. Materials and Methods: The exposure factors applied for real pa ents in four age groups (5, 10, 15-year-old and adult) were obtained for conven onal dental radiographies, periapical, bitewing, and panoramic. The dose-area product (DAP) values were measured for every dental radiographies. The risk of exposure-induced cancer death (REID) was es mated for every dental radiographies in different age groups and in both genders. Results: The range of the REID values in periapical radiography were 1.3 to 20.9 per ten million for male pa ents, and 1.6 to 28.3 per ten million for female pa ents in different age groups. The range of REID values in bitewing radiography were 1.5 to 11.2 per ten million for male, and 1.9 to 13.2, per ten million for female in different age groups. The mean of REID values in panoramic radiography were 7.32, 4.70, 3.55, and 2.1 per ten million for male pa ents in 5-, 10-, and 15-year-old and adult age groups, respec vely, and were 9.43, 5.86, 4.25 and 2.41 per ten million for female pa ents in 5, 10, 15-year-old and adult age groups, respec vely. Conclusion: In accordance with the results of the present study, the overall risk of cancer from radia on in children was more than adult and in female pa ents is more than male pa ents in dental X-ray examina ons.

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Digital radiography (DR) systems have been recently introduced as a developed technology that is replacing conventional film–screen systems in many countries around the world. Ideal situation in radiography is to maximize the image quality while minimizing the patient dose. The purpose of this study was to compare image quality and radiation dose in different digital radiography systems. Four different digital systems are compared in terms of their image quality performance and dose area product (DAP). Images of Pehamed FLUORAD A + D phantom were obtained for each DR system. Image quality parameters (contrast resolution (CR), spatial resolution (SR), and contrast-to-noise ratio (CNR)) and DAP were significantly different between different digital systems. It was shown that all four quantities increased with increasing exposure parameters in all systems. Image quality parameters of the SEDECAL system were higher than that in other systems (p ≤ 0.05). At the stable DAP (100 mGy.cm2), means of CR, CNR, and SR in the SEDECAL system were 6.38 ± 0.797, 29.70 ± 0.85 and 3.10 ± 0.38 lp/mm, respectively. The results of this investigation can be taken into consideration in the selection and purchasing of new systems in order to preserve patients as well as radiographers from unnecessary radiation dose.