skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Response Funtions for Computing Absorbed Dose to Skeletal Tissues from Photon Irradiation

Abstract

The calculation of absorbed dose in skeletal tissues at radiogenic risk has been a difficult problem because the relevant structures cannot be represented in conventional geometric terms nor can they be visualised in the tomographic image data used to define the computational models of the human body. The active marrow, the tissue of concern in leukaemia induction, is present within the spongiosa regions of trabecular bone, whereas the osteoprogenitor cells at risk for bone cancer induction are considered to be within the soft tissues adjacent to the mineral surfaces. The International Commission on Radiological Protection (ICRP) recommends averaging the absorbed energy over the active marrow within the spongiosa and over the soft tissues within 10 mm of the mineral surface for leukaemia and bone cancer induction, respectively. In its forthcoming recommendation, it is expected that the latter guidance will be changed to include soft tissues within 50 mm of the mineral surfaces. To address the computational problems, the skeleton of the proposed ICRP reference computational phantom has been subdivided to identify those voxels associated with cortical shell, spongiosa and the medullary cavity of the long bones. It is further proposed that the Monte Carlo calculations with these phantoms compute themore » energy deposition in the skeletal target tissues as the product of the particle fluence in the skeletal subdivisions and applicable fluence-to-dose response functions. This paper outlines the development of such response functions for photons.« less

Authors:
 [1];  [2];  [3];  [3]
  1. ORNL
  2. University of Florida, Gainesville
  3. Institute of Radiation Protection, GSF-National Reserach Center for Environ
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
ORNL other overhead
OSTI Identifier:
934948
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Radiation Protection Dosimetry; Journal Volume: 127; Journal Issue: 1-4
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; INDUCTION; IRRADIATION; LEUKEMIA; NEOPLASMS; PHANTOMS; PHOTONS; RADIATION DOSES; RADIATION PROTECTION; RESPONSE FUNCTIONS; SKELETON; TARGETS; TRABECULAR BONE

Citation Formats

Eckerman, Keith F, Bolch, W E, Zankl, M, and Petoussi-Henss, N. Response Funtions for Computing Absorbed Dose to Skeletal Tissues from Photon Irradiation. United States: N. p., 2007. Web. doi:10.1093/rpd/ncm468.
Eckerman, Keith F, Bolch, W E, Zankl, M, & Petoussi-Henss, N. Response Funtions for Computing Absorbed Dose to Skeletal Tissues from Photon Irradiation. United States. doi:10.1093/rpd/ncm468.
Eckerman, Keith F, Bolch, W E, Zankl, M, and Petoussi-Henss, N. Mon . "Response Funtions for Computing Absorbed Dose to Skeletal Tissues from Photon Irradiation". United States. doi:10.1093/rpd/ncm468.
@article{osti_934948,
title = {Response Funtions for Computing Absorbed Dose to Skeletal Tissues from Photon Irradiation},
author = {Eckerman, Keith F and Bolch, W E and Zankl, M and Petoussi-Henss, N},
abstractNote = {The calculation of absorbed dose in skeletal tissues at radiogenic risk has been a difficult problem because the relevant structures cannot be represented in conventional geometric terms nor can they be visualised in the tomographic image data used to define the computational models of the human body. The active marrow, the tissue of concern in leukaemia induction, is present within the spongiosa regions of trabecular bone, whereas the osteoprogenitor cells at risk for bone cancer induction are considered to be within the soft tissues adjacent to the mineral surfaces. The International Commission on Radiological Protection (ICRP) recommends averaging the absorbed energy over the active marrow within the spongiosa and over the soft tissues within 10 mm of the mineral surface for leukaemia and bone cancer induction, respectively. In its forthcoming recommendation, it is expected that the latter guidance will be changed to include soft tissues within 50 mm of the mineral surfaces. To address the computational problems, the skeleton of the proposed ICRP reference computational phantom has been subdivided to identify those voxels associated with cortical shell, spongiosa and the medullary cavity of the long bones. It is further proposed that the Monte Carlo calculations with these phantoms compute the energy deposition in the skeletal target tissues as the product of the particle fluence in the skeletal subdivisions and applicable fluence-to-dose response functions. This paper outlines the development of such response functions for photons.},
doi = {10.1093/rpd/ncm468},
journal = {Radiation Protection Dosimetry},
number = 1-4,
volume = 127,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • Quantitative radiation dose-response curves for normal gustatory tissue in man were studied. Taste function, expressed as taste loss, was evaluated in 84 patients who were given either photon or neutron radiotherapy for tumors in the head and neck region. Patients were treated to average tumor doses of 6600 cGy (photon) or 2200 cGy intervals for photon patients and 320-cGy intervals for neutron patients during radiotherapy. The dose-response curves for photons and neutrons were analyzed by fitting a four-parameter logistic equation to the data. Photon and neutron curves differed principally in their relative position along the dose axis. Comparison of themore » dose-response curves were made by determination of RBE. At 320 cGy, the lowest neutron dose at which taste measurements were made, RBE = 5.7. If this RBE is correct, then the therapeutic gain factor may be equal to or less than 1, indicating no biological advantage in using neutrons over photons for this normal tissue. These studies suggest measurements of taste function and evaluation of dose-response relationships may also be useful in quantitatively evaluating the efficacy of chemical modifiers of radiation response such as hypoxic cell radiosensitizers and radioprotectors.« less
  • No abstract prepared.
  • A formalism is derived that relates the absorbed dose to a medium from photon and electron beams to the photon calibration factor of an ionization chamber. The formalism is applicable to the photon and electron beam energies that are currently of interest in radiation therapy. It is developed in terms of a cavity-gas calibration factor, a quantity characteristic of the chamber and independent of the energy of the calibration beam assuming the energy expended per ion pair is energy independent. The cavity-gas calibration factor can be obtained from a chamber calibration performed in terms of exposure,absorbed dose to water,or airmore » kerma. The perturbation corrections due to replacement of the surrounding medium by the chamber wall and cavity are identified as ratios of the photon energy fluence,or the electron fluence, at the position of the chamber center. The unmanageable complexities of a theory that covers an ionization chamber made of several materials are avoided by limiting the development to a chamber made of a single material with the expectation that the inhomogeneities of real chambers can be treated as perturbations. Attention is called to certain theoretical aspects of this dosimetry development that do not appear to have been previously recognized.« less
  • A protocol is given to provide radiological physicists with an accurate means of measuring radiation doses on phantoms. Plastics, as well as water, are considered as phantoms. A new quantity, the cavity-gas calibration factor, is introduced.(AIP)