Estimation of organ doses from diagnostic x-rays for dose reconstruction.
Davidson-GR; Kathren-RL; Shockley-VE; Thomas-EM
Health Phys 2005 Jul; 89(1)(Suppl S):S53
ICRP Publication 34 provides dose factors that can be used to estimate doses to selected organs of a patient from diagnostic x-ray examinations. The factors are based on Monte Carlo calculations for reference phantoms. For adult patients, factors are provided for seven organs for standard x-ray projection geometries involving well-collimated beams. Reconstruction of occupational medical doses to claimants under the Energy Employees Occupational Illness Compensation Program Act may require estimates of doses to organs not treated in ICRP 34 and estimates for x-rays taken in earlier periods using different geometries with less collimation. This presentation describes a method for using the ICRP 34 dose factors to make order-of-magnitude estimates of doses to all parts of the body for such situations. The approach is based on the determination of organ location relative to the beam and the use of published x-ray scattering and penetration data. The method has been applied to the estimation of doses due to pelvis AP x rays taken using parameters reported in use prior to 1958. Doses were estimated for organs inside and outside the beam and for different regions of skin on the exit side of the body. For an entrance kerma of 1.68 cGy and a 2 mm AI HVL beam, doses to the lungs and thyroid were estimated as 1.29E-01 and 1.38E-03 cGy, respectively. This compared with values of 1.04E-01 and 2.68E-04 cGy, respectively, which were calculated independently using Monte-Carlo based dose factors.
X-ray-analysis; Organs; Dose-response; Dosimetry; Occupational-health; Occupational-exposure; Occupational-medicine
Abstract; Conference/Symposia Proceedings