Introduction: Body mass index (BMI) is one of the critical factors affecting the radiation dose received by the patient because the patients with higher BMI have higher attenuation factor, therefore the higher exposure parameters must be used. Purpose: The aim of the study was to investigate how BMI affects the DAP, effective dose and dose to selected radiosensitive organs during various examinations in general radiography. Methods: Dose was measured in 600 patients referred for imaging of the chest, lumbar spine, pelvis, knees, and shoulder in general radiography. The height and weight of the patients were measured and from this the BMI for each patient was calculated. Patients were then categorized into three different groups based on their BMI (normal weight patients, overweight patients, and obese patients). The DAP value for each imaging was compiled, and the effective dose and absorbed dose for selected radiosensitive organs were calculated using PCXMC 2.0 Monte Carlo simulation program. Results: The DAP and effective dose values increased in overweight and obese patients in the trunk region. The DAP values were on average more than 29% higher in PA and more than 59% higher in lateral projection in overweight patients in chest imaging, more than 62% higher in AP and more than 46% higher in lateral projection in lumbar imaging, and more than 69% higher in pelvic imaging. In obese patients, the increase in DAP values was more than 96% in PA projection and more than 216% in lateral projection for chest imaging, more than 272% in AP and more than 117% in lateral projection for lumbar spine imaging and more than 291% in pelvic imaging. The DAP values for knee and shoulder radiography showed only slightly lower dose values for overweight and obese patients. The values of effective dose and absorbed dose for selected radiosensitive organs corresponded with the increase in DAP values. Discussion and conclusion: From the results presented, we can conclude that BMI has a large effect on DAP, effective dose, and dose to selected radiosensitive organs chest imaging, lumbar spine, and pelvic imaging, and a smaller effect for knee and shoulder imaging in general radiography. This is because we did not use automatic exposure control for the imaging of the extremities.
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