Effective dose and energy imparted in diagnostic radiology.
The patient effective dose, E, is an indicator of the stochastic radiation risk associated with radiographic or fluoroscopic x-ray examinations. Determining effective doses for radiologic examinations by measurement or calculation is generally very difficult. By contrast, the energy imparted, epsilon, to the patient may be obtained from the x-ray exposure-area product incident on the patient. As energy imparted is approximately proportional to the effective dose for any given x-ray radiographic view, the availability of E/epsilon ratios for common radiographic projections provides a convenient way for estimating effective doses. Ratios of E/epsilon were obtained for 68 projections using E and epsilon values obtained from published dosimetry data computed using Monte Carlo techniques on an adult anthropomorphic phantom. The average E/epsilon ratio for the 68 projections in adults was 17.8+/-1.4 mSv/J, whereas uniform whole body irradiation corresponds to 14.1 mSv/J. The major determinant of E/epsilon ratios was the projection employed (the body region irradiated and x-ray beam orientation), whereas the tube potential and beam filtration were of secondary importance. Adult E/epsilon ratios may also be used to obtain effective doses to pediatric patients undergoing x-ray examinations by application of a correction factor based on the patient mass.
Huda
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W
Department of Radiology, University of Florida, Gainesville 32610-0374, USA. hudaw@vax.cs.hscsyr.edu
Gkanatsios
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D000328:Adult; D055592:Biophysical Phenomena; D001703:Biophysics; D002648:Child; D006801:Humans; D007231:Infant, Newborn; D009010:Monte Carlo Method; D009928:Organ Specificity; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods* / Q000706:statistics & numerical data