Related Experiment Video
Updated: Aug 15, 2026

Characterization of Recombination Effects in a Liquid Ionization Chamber Used for the Dosimetry of a Radiosurgical Accelerator
Published on: May 9, 2014
Relations between effective dose equivalent and mean absorbed dose (energy imparted) to patients in diagnostic
Abstract:
Values of HE/D, the ratio of the effective dose equivalent HE to the mean absorbed dose D to the total body, have been derived as a function of beam quality (HVT) for a variety of Roentgen diagnostic examinations of the adult trunk and head, using tabulations from the literature. Problems in specifying beam quality are discussed. The energy epsilon imparted to the patient can, in Roentgen diagnostic examinations, be determined using a transmission chamber. Since, however, HB/epsilon depends more critically than HE/D on the mass M of the patient (D = epsilon/M), the latter quantity is preferred for risk assessment. HE/D takes values in the range 0.44-2.8 Sv Gy-1. This includes the value 1 Sv Gy-1 resulting from a uniform whole-body irradiation independent of M. The corresponding value of HE/epsilon = 1/M Sv J-1 if M is in kg. It is therefore recommended that clinical measurements of epsilon be supplemented by measurements of the patient's mass so that D = epsilon/M can be estimated and tabulations of organ absorbed doses be supplemented with values of D so as to allow accurate derivation of the ratio HE/D. In optimising the technical parameters of a given examination using the transmission chamber, HE/D as a function of beam quality must be known.
Related Concept Videos
Biological Effects of Radiation
X-ray Imaging
Positron Emission Tomography
One of the main requirements of a PET scan is a positron-emitting radioisotope, which is produced in a cyclotron and then attached to a substance used by the part of the body being...
Absorption of Radiation
Radiological Investigation I: X-ray and CT
Pharmacokinetic–Pharmacodynamic Relationship: Exposure, Response and Effect

