Personal dose equivalent for photons and its variation with dosimeter position

Health Phys. 1999 Feb;76(2):162-70. doi: 10.1097/00004032-199902000-00008.


This work presents conversion coefficients per air kerma free-in-air for the personal dose equivalent, Hp(10), calculated according to its definition by the International Commission on Radiation Units and Measurements as a quantity in the human body. The values were calculated using Monte Carlo methods for various dosimeter positions in the trunk of a voxel model of an adult male, and they are given for various directions of incidence of broad parallel photon beams with energies between 10 keV and 10 MeV. It is shown that the numerical values of the personal dose equivalent depend on the exact position of the dosimeter, with maximum differences between 12% and 80%, depending on the beam geometry. It is further shown that the recommended calibration quantity Hp slab(10), which has been used in ICRP Publication 74 and ICRU Report 57 in the absence of data in the human body to approximate personal dose equivalent, does represent the latter quantity in a sensible way for some, but not all, beam geometries. Comparison of the values for the personal dose equivalent of this work with effective dose revealed that Hp(10) is a conservative estimate or close approximation of E for most irradiation geometries and photon energies.

MeSH terms

  • Adult
  • Body Height
  • Calibration
  • Humans
  • Male
  • Phantoms, Imaging*
  • Photons*
  • Radiation Dosage*
  • Radiation Protection*
  • Thyroid Gland