چاپ صفحه |  صفحه نخست سامانه |  نویسندگان |  اطلاعات تفضیلی |  دانلود مقاله | دانشگاه علوم پزشکی تبریز |
| نویسنده | نفر چندم مقاله |
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| رامین قاسمی شایان | اول |
| عنوان | متن |
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| خلاصه مقاله | Background Chest radiography (CXR) is one of the most utilized imaging investigations involving radiation across many medical specialties ; it is of value for solving a wide range of clinical problems. X-ray images of the chest provide important information for deciding upon further steps in the establishment of a diagnosis, treatment and follow-up procedure. Chest radiography remains the mainstay for diagnosis of many pulmonary diseases, even despite recent developments in cross sectional imaging of the thorax, particularly computed tomography (CT). Advantages of chest radiography over cross sectional imaging are lower cost, lower dose and speed of acquisition and diagnosis. The individual radiation dose of a CXR to the patient is relatively low, however, due to its frequent use, the contribution of the accumulated dose is substantial. Consequently, optimization of dose and image quality remains a challenging area of research and demonstrates lower radiation dose with similar image quality. Methods Dose in digital chest radiography mainly affects the noise in the images. Noise in radiography can be defined as uncertainty or imprecision of the recording of an image, i.e. unwanted stochas-tic fluctuations in the image. The most disturbing effect on image quality (and thereby on diagnosis) is that noise can cover or reduce the visibility of certain structures. The loss of visibility is especially significant for low contrast objects. According to examination done in department of radiology in Leiden University of Medical Center in Netherlands ( WouterJ.H. Veldkamp, Lucia J.M. Kroft, Jacob Geleijns-European Journal of Radiology ) chest radiographs of 20 patients (both PA and lateral images) with a variety of chest pathologies were used to simulate reduced dose levels corresponding to 50%, 25% and 12% of the original dose. For each patient the images were displayed as hard copies on the film-viewing box in random order. Four radiologists ranked the quality of the corresponding images and rated diagnostic quality. The 100% reference dose was not recognized as the best quality image in nearly half of the cases. Larger dose reductions to 25% and 12% were usually recognized as third and fourth best quality. The 100% reference dose was not recognized as the best quality image in nearly half of the cases. Larger dose reductions to 25% and 12% were usually recognized as third and fourth best quality. The preliminary subjective findings suggested therefore that a 50% dose reduction seems feasible in a variety of chest pathologies. However, further dose reduction (more than 50%) clearly reduced the perceived diagnostic quality. Another study which demonstrates lower radiation dose with similar image quality done by ESR ( Y.-H. Wan1,M. H. Lai,C. Y. Chu,K. Tang,T. M. Chan,J. L. S. Khoo;HongKong/CN,HongKong/HK ) demonstrated that CXRs taken with sensitivity 600 effectively reduced the radiation dose to patient while maintaining sufficient image quality as compared with sensitivity 400, and should be applied to future standard CXRs acquisition. Conclusion Chest radiography is the most commonly performed diagnostic X-ray examination. The radiation dose to the patient for this examination is relatively low but because of its frequent use, the contribution to the collective dose is considerable. Consequently, optimization of dose and image quality offers a challenging area of research. Lower radiation dose with similar image quality is the most indispensable factor and way to perform a safety examination. Results show that lowering radiation factors ( Kvpand mas ) have less or no effect on image quality. |
| کلمات کلیدی | CXR-Dose-Radiation factors-Digital radiography |
| نام فایل | تاریخ درج فایل | اندازه فایل | دانلود |
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| evaluation.jpg | 1398/11/16 | 230705 | دانلود |
