Computation of energy imparted in diagnostic radiology.

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.

[1]  B. Wall,et al.  Doses to patients from pantomographic and conventional dental radiography. , 1979, The British journal of radiology.

[2]  R. Harrison A re-evaluation of the 'saturated scatter' method for estimating the energy imparted to patients during diagnostic radiology examinations. , 1983, Physics in medicine and biology.

[3]  Patient dosimetry in diagnostic radiology-some practical considerations in an NHS region , 1995 .

[4]  P. Shrimpton,et al.  The measurement of energy imparted to patients during diagnostic x-ray examinations using the Diamentor exposure-area product meter. , 1984, Physics in medicine and biology.

[5]  C CARLSSON,et al.  DETERMINATION OF INTEGRAL ABSORBED DOSE FROM EXPOSURE MEASUREMENTS. , 1963, Acta radiologica: therapy, physics, biology.

[6]  J. Persliden,et al.  Energy imparted to the patient in diagnostic radiology: calculation of conversion factors for determining the energy imparted from measurements of the air collision kerma integrated over beam area. , 1984, Physics in medicine and biology.

[7]  J M Boone Parametrized x-ray absorption in diagnostic radiology from Monte Carlo calculations: implications for x-ray detector design. , 1992, Medical physics.

[8]  J Persliden,et al.  Energy imparted to water slabs by photons in the energy range 5-300 keV. Calculations using a Monte Carlo photon transport model. , 1984, Physics in medicine and biology.

[9]  W. Huda,et al.  Radiation doses and detriment from chest x-ray examinations. , 1989, Physics in medicine and biology.

[10]  W. Huda,et al.  Effective dose equivalents, HE, in diagnostic radiology. , 1990, Medical physics.

[11]  C. Polvani [From the Publication 9 to the Publication 26 of the International Commission on Radiological Protection (ICRP) (author's transl)]. , 1979, La Medicina del lavoro.

[12]  B. Wall,et al.  Organ Doses from Medical X-Ray Examinations Calculated Using Monte Carlo Techniques , 1985 .

[13]  D. Dance,et al.  The physical performance of different x-ray contrast agents: calculations using a Monte Carlo model of the imaging chain. , 1995, Physics in medicine and biology.

[14]  G. Barnes,et al.  Semiempirical model for generating tungsten target x-ray spectra. , 1991, Medical physics.

[15]  H. Griffiths 1990 Recommendations of the International Commission on Radiological Protection. Annals of the ICRP Publication 60 , 1992 .

[16]  W. Huda,et al.  How will the new definition of 'effective dose' modify estimates of dose in diagnostic radiology? , 1991 .

[17]  J. Malone,et al.  An International Intercomparison of Dose-Area Product Meters , 1992 .

[18]  M Sandborg,et al.  Evaluation of image quality in fluoroscopy by measurements and Monte Carlo calculations. , 1995, Physics in medicine and biology.

[19]  Å. Cederblad,et al.  Radiation Doses to Patients and Personnel Involved in Embolization of Intracerebral Arteriovenous Malformations , 1991, Acta radiologica.