ABSTRACT Pediatric effective doses can be obtained for any radiologic examination using the selected radiographic technique factors (kV/mAs), the exposure geometry and the patient mass. The energy imparted ε to the patient may be computed from the exposure area product, x-ray tube voltage, half-value layer and patient thickness. Values of energy imparted may be subsequently converted to an effective dose E using published radiographic projection specific E/ε ratios determined using Monte Carlo techniques applied to anthropomorphic phantoms, with a correction applied for the patient mass. Pediatric effective doses (head, chest, abdomen and extremity) were computed for representative adult patients, as well as for pediatric patients ranging from new born to 15 year old youths. Values of patient effective dose were dependent on body size, selected technique factors as well as the type of radiographic imaging equipment used, with no clear trends for effective dose with patient age.

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Available from: Robert J Botash, Oct 24, 2014
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    ABSTRACT: 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.
    Medical Physics 09/1997; 24(8):1311-6. DOI:10.1118/1.598153 · 3.01 Impact Factor
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    British Journal of Radiology 10/1998; 71(849):994-5. DOI:10.1259/bjr.71.849.10195022 · 1.53 Impact Factor
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    ABSTRACT: Energy imparted is a measure of the total ionizing energy deposited in the patient during a radiologic examination and may be used to quantify the patient dose in diagnostic radiology. Values of the energy imparted per unit exposure-area product, omega (z), absorbed by a semi-infinite water phantom with a thickness z, were computed for x-ray spectra with peak x-ray tube voltages ranging from 50-140 kV and with added filtration, ranging from 1-6 mm aluminum. For a given phantom thickness and peak x-ray tube voltage, the energy imparted was found to be directly proportional to the x-ray beam half-value layer (HVL) expressed in millimeters of aluminum. Values of omega (z) were generated for constant waveform x-ray tube voltages and an anode angle of 12 degrees, and were fitted to the expression omega (z) = alpha x HVL + beta. Fitted alpha and beta parameters are provided that permit the energy imparted to be determined for any combination of tube voltage, half-value layer, and phantom thickness from the product of the entrance skin exposure (free-in-air) and the corresponding x-ray beam area. The results obtained using our method for calculating energy imparted were compared with values of energy imparted determined using Monte Carlo techniques and anthropomorphic phantoms for a range of diagnostic examinations. At 60, 80, and 120 kV, absolute values of energy imparted obtained using our method differed by 8%, 10%, and 12%, respectively, from the corresponding results of Monte Carlo computations obtained for an anthropomorphic phantom. The method described in this paper permits a simple determination of energy imparted for any type of diagnostic x-ray examination which may be used to compare the radiologic risks from differing types of x-ray examinations, optimize imaging techniques with respect to the patient dose, or estimate the patient effective dose equivalent.
    Medical Physics 05/1997; 24(4):571-9. DOI:10.1118/1.597939 · 3.01 Impact Factor