Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Influence of the X-ray beam quality on the dose increment in CT with iodinated contrast medium

Influence of the X-ray beam quality on the dose increment in CT with iodinated contrast medium BACKGROUND:In computed tomography (CT), the image contrast is given by the difference in X-ray attenuation in the various tissues of the patient and contrast media are used to enhance image contrast in anatomic regions characterized by similar attenuation coefficients.OBJECTIVE:Aim of the present work is to enlarge the range of applicability of the method previously introduced for organ dosimetry in contrast-enhanced CT, by studying the effects of X-ray beam quality on the parameters of the model. Furthermore, an experimental method for the evaluation of the attenuation properties of iodinated solutions is proposed.METHODS:Monte Carlo simulations of anthropomorphic phantoms were carried out to determine a bi-parametrical (a and b) analytical relationship between iodine concentration and dose increase in organs of interest as a function of the tube kilo-voltage peak potential (kVp) and filtration. Experimental measurements of increments in Hounsfield Units (HU) were conducted in several CT scanners, at all the kVp available, in order to determine the parameter γ which relates the HU increment with the iodine mass fraction. A cylindrical phantom that can be filled with iodine solutions provided with an axial housing for a pencil ionization chamber was designed and assembled in order to measure the attenuation properties of iodine solutions under irradiation of a CT scanner and to obtain a further validation of Monte Carlo simulations.RESULTS:The simulation-derived parameters of the model, a and b, are only slightly dependent upon the tube kilo-voltage peak potential and filtration, while such scanner-dependent features influence mainly the experimentally-derived γ parameter. Relative dose variations registered by the ionization chamber inside the iodine-filled cylindrical phantom decrease when the X-ray mean energy increases, and reaches about 50% for 10 mg/ml of iodine.CONCLUSIONS:The dosimetric method for contrast-enhanced CT can be applied to all CT scanners by adopting average simulative parameters and by carrying out a simple measurement with a series of iodine contrast solutions. The novel experimental methodology introduced can provide a direct measurement of iodine attenuation properties. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of X-Ray Science and Technology IOS Press

Influence of the X-ray beam quality on the dose increment in CT with iodinated contrast medium

Download PDF
12 pages

Loading next page...
 
/lp/ios-press/influence-of-the-x-ray-beam-quality-on-the-dose-increment-in-ct-with-uSyneQ7s4m

References

References for this paper are not available at this time. We will be adding them shortly, thank you for your patience.

Publisher
IOS Press
Copyright
Copyright © 2016 IOS Press and the authors. All rights reserved
ISSN
0895-3996
eISSN
1095-9114
DOI
10.3233/XST-160551
pmid
27002906
Publisher site
See Article on Publisher Site

Abstract

BACKGROUND:In computed tomography (CT), the image contrast is given by the difference in X-ray attenuation in the various tissues of the patient and contrast media are used to enhance image contrast in anatomic regions characterized by similar attenuation coefficients.OBJECTIVE:Aim of the present work is to enlarge the range of applicability of the method previously introduced for organ dosimetry in contrast-enhanced CT, by studying the effects of X-ray beam quality on the parameters of the model. Furthermore, an experimental method for the evaluation of the attenuation properties of iodinated solutions is proposed.METHODS:Monte Carlo simulations of anthropomorphic phantoms were carried out to determine a bi-parametrical (a and b) analytical relationship between iodine concentration and dose increase in organs of interest as a function of the tube kilo-voltage peak potential (kVp) and filtration. Experimental measurements of increments in Hounsfield Units (HU) were conducted in several CT scanners, at all the kVp available, in order to determine the parameter γ which relates the HU increment with the iodine mass fraction. A cylindrical phantom that can be filled with iodine solutions provided with an axial housing for a pencil ionization chamber was designed and assembled in order to measure the attenuation properties of iodine solutions under irradiation of a CT scanner and to obtain a further validation of Monte Carlo simulations.RESULTS:The simulation-derived parameters of the model, a and b, are only slightly dependent upon the tube kilo-voltage peak potential and filtration, while such scanner-dependent features influence mainly the experimentally-derived γ parameter. Relative dose variations registered by the ionization chamber inside the iodine-filled cylindrical phantom decrease when the X-ray mean energy increases, and reaches about 50% for 10 mg/ml of iodine.CONCLUSIONS:The dosimetric method for contrast-enhanced CT can be applied to all CT scanners by adopting average simulative parameters and by carrying out a simple measurement with a series of iodine contrast solutions. The novel experimental methodology introduced can provide a direct measurement of iodine attenuation properties.

Journal

Journal of X-Ray Science and Technology – IOS Press

Published: Jan 1, 2016

References

  • Sparsity-regularized image reconstruction of decomposed K-edge data in spectral CT
    Xu
  • Automatic detection method of hepatocellular carcinomas using the non-rigid registration method of multi-phase liver CT images
    Lee
  • Aortic dual-energy CT angiography with low contrast medium injection rate
    Liu
  • Radiation dose enhancement in tumors with iodine
    Santos Mello
  • Recurrent CT, Cumulative radiation exposure, and associated radiation-induced cancer risks from CT of adults
    Sodickson
  • Relationships between physical dose quantities and patient dose in CT
    Hidajat
  • Dose distributions using kilovoltage x-rays and dose enhancement from iodine contrast agents
    Mesa
  • Calculation of radiation dose enhancement factors for dose enhancement therapy of brain tumours
    Solberg
  • Radiochromic film dosimetry of contrast-enhanced radiotherapy (CERT)
    Morris
  • Monte Carlo simulation of contrast-enhanced whole brain radiotherapy on a CT scanner
    Schultz
  • Dosimetric and microdosimetric study of contrast-enhanced radiotherapy with kilovolt x-rays
    Verhaegen
  • Microdosimetric analysis of various mammography spectra: Lineal energy distributions and ionization cluster analysis
    Verhaegen
  • The presence of iodinated contrast agents amplifies DNA radiation damage in computed tomography
    Pathe
  • Effect of radiation and contrast media on chromosomes, Preliminary report
    Adams
  • Cytogenetic effects of contrast material in patients undergoing excretory urography
    Cochran
  • Chromosome damage from nonionic contrast media
    Cochran
  • Synchrotron radiation-based experimental determination of the optimal energy for cell radiotoxicity enhancement following photoelectric effect on stable iodinated compounds
    Corde
  • Iodinated contrast agents as ‘radiosensitizers’
    Dawson
  • Synergistic cytotoxicity of iodinated contrast agents and x-radiation
    Dawson
  • Enhanced radio sensitivity with iodinated contrast agents using monochromatic synchrotron x-rays on human cancerous cells
    Esteve
  • Radiation dose enhancement therapy with iodine in rabbit VX-2 brain tumors
    Iwamoto
  • The CT scanner as a therapy machine
    Iwamoto
  • The influence of x-ray contrast agents in computed tomography on the induction of dicentrics and gamma-H2AX foci in lymphocytes of human blood samples
    Jost
  • A method to evaluate the dose increase in CT with iodinated contrast medium
    Amato
  • Can contrast medium increase organ radiation doses in CT examinations? A clinical study
    Amato
  • GEANT4 - a simulation toolkit
    Agostinelli
  • Validation of Geant4 simulation of electron energy deposition
    Batic
  • Geant4 applicability and validation for photons and electrons in radiotherapy
    Malthez
  • An accurate method for computer-generating tungsten anode X-ray spectra from 30 to 140kV
    Boone
  • Monte Carlo study of voxel S factor dependence on tissue density and atomic composition
    Amato
  • Monte Carlo study of the dose enhancement effect of gold nanoparticles during X-ray therapies and evaluation of the anti-angiogenic effect on tumour capillary vessels
    Amato
  • Absorbed fractions in ellipsoidal volumes for ß- radionuclides employed in internal radiotherapy
    Amato