title: Phantom-derived estimation of effective dose equivalent from X rays with and without a lead apron.
abstract: Organ dose equivalents were measured in a humanoid phantom in order to estimate effective dose equivalent (H(E)) and effective dose (E) from low-energy x rays and in the presence or absence of a protective lead apron. Plane-parallel irradiation conditions were approximated using direct x-ray beams of 76 and 104 kVp and resulting dosimetry data was adjusted to model exposures conditions in fluoroscopy settings. Values of H(E) and E estimated under-shielded conditions were compared to the results of several recent studies that used combinations of measured and calculated dosimetry to model exposures to radiologists. While the estimates of H(E) and E without the lead apron were within 0.2 to 20% of expected values, estimates based on personal monitors worn at the (phantom) waist (underneath the apron) underestimated either H(E) or E while monitors placed at the neck (above the apron) significantly overestimated both quantities. Also, the experimentally determined H(E) and E were 1.4 to 3.3 times greater than might be estimated using recently reported "two-monitor" algorithms for the estimation of effective dose quantities. The results suggest that accurate estimation of either H(E) or E from personal monitors under conditions of partial body exposures remains problematic and is likely to require the use of multiple monitors.
authors.affiliation: University of Pittsburgh, Department of Environmental and Occupational Health, PA 15238, USA.
authors.forename: C F
authors.initials: CF
authors.lastname: Mateya
authors.forename: H G
authors.initials: HG
authors.lastname: Claycamp
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D005471:Fluoroscopy; D006801:Humans; D007854:Lead; D016273:Occupational Exposure; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000379:methods*; D011835:Radiation Protection; D013819:Thermoluminescent Dosimetry
chemical_list: D007854:Lead