AAPM Banner
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

You are not logged in Access to this article requires a subscription. Log In

Medical Physics / Volume 37 / Issue 7 / RADIATION MEASUREMENT PHYSICS

Med. Phys. 37, 3569 (2010); http://dx.doi.org/10.1118/1.3432567 (7 pages)

The energy dependence of lithium formate and alanine EPR dosimeters for medium energy x rays

Einar Waldeland and Eirik Malinen

Department of Medical Physics, The Norwegian Radium Hospital, Oslo University Hospital, N-0310 Oslo, Norway and Department of Physics, University of Oslo, P.O. Box 1048, Blindern, N-0316 Oslo, Norway

Eli Olaug Hole and Einar Sagstuen

Department of Physics, University of Oslo, P.O. Box 1048, Blindern, N-0316 Oslo, Norway

View MapView Map

(Received 22 February 2010; accepted 1 May 2010; revised 10 April 2010; published online 15 June 2010)

Full Text: Read Online (HTML) | Download PDF | Buy PDF (US$30) | View Cart
Purpose: To perform a systematic investigation of the energy dependence of alanine and lilthium formate EPR dosimeters for medium energy x rays.
Methods: Lithium formate and alanine EPR dosimeters were exposed to eight different x-ray beam qualities, with nominal potentials ranging from 50 to 200 kV. Following ionometry based on standards of absorbed dose to water, the dosimeters were given two different doses of approximately 3 and 6 Gy for each radiation quality, with three dosimeters for each dose. A reference series was also irradiated to three different dose levels at a 60Co unit. The dose to water energy response, that is, the dosimeter reading per absorbed dose to water relative to that for 60Co γ-rays, was estimated for each beam quality. In addition, the energy response was calculated by Monte Carlo simulations and compared to the experimental energy response.
Results: The experimental energy response estimates ranged from 0.89 to 0.94 and from 0.68 to 0.90 for lithium formate and alanine, respectively. The uncertainties in the experimental energy response estimates were typically 3%. The relative effectiveness, that is, the ratio of the experimental energy response to that following Monte Carlo simulations was, on average, 0.96 and 0.94 for lithium formate and alanine, respectively.
Conclusions: This work shows that lithium formate dosimeters are less dependent on x-ray energy than alanine. Furthermore, as the relative effectiveness for both lithium formate and alanine were systematically less than unity, the yield of radiation-induced radicals is decreased following x-irradiation compared to irradiation with 60Co γ-rays.

© 2010 American Association of Physicists in Medicine

ACKNOWLEDGMENTS

The authors thank Mrs. Ingerid Skjei Knudtsen for her assistance with measurements of x-ray potentials. This work was supported by Southern and Eastern Norway Regional Health Authority (Grant No. 39203).

Article Outline

  1. INTRODUCTION
  2. MATERIALS AND METHODS
    1. Dosimeters and EPR readings
    2. X-ray beam qualities and irradiation
    3. Dosimetry
    4. Monte Carlo simulations
    5. Energy dependence and relative effectiveness
    6. Uncertainties
  3. RESULTS
  4. DISCUSSION
Digital Object Identifier
http://dx.doi.org/10.1118/1.3432567

KEYWORDS and PACS

Keywords

dosimetry, molecular biophysics, Monte Carlo methods, paramagnetic resonance, proteins, radiation therapy, water, X-ray applications, photons, kV, x-ray, energy dependence, electron paramagnetic resonance, lithium formate, alanine, dosimetry, radiotherapy

PACS

PUBLICATION DATA

ISSN

0094-2405 (print)  

Publisher

$abstract.society.value is a Member of CrossRef American Association of Physicists in Medicine

For access to fully linked references, you need to log in.

For access to citing articles, you need to log in.


Figures (4) Tables (4)

Access to article objects (figures, tables, multimedia) requires a subscription; log in to view available files.
(Access to supplementary files, where available, is free for this journal.)

Access to article objects (figures, tables, multimedia) requires a subscription; log in to view available files.
(Access to supplementary files, where available, is free for this journal.)



Close

Medical Physics is an official science journal of the AAPM and of the COMP/CCPM/IOMP
William R. Hendee, Editor
Departments of Radiology, Radiation Oncology, Biophysics, Community and Public Health, Medical College of Wisconsin
One Physics Ellipse
College Park, Maryland 20740
301-209-3352

© 2012, American Association of Physicists in Medicine. Individual readers of this journal, and nonprofit libraries acting for them, are freely permited to make fair use of the material in it, such as to copy an article for use in teaching or research. (For other kinds of copying see "Copying Fees.") Permission is granted to quote from this journal in scientific works with the customary acknowledgment of the source. To reprint a figure, table, or other excerpt requires, in addition, AAPM may require that permission also be obtained from one of the authors. Address inquiries and notices to Penny Slattery, Journal Manager, Medical Physics Journal, AAPM, One Physics Ellipse, College Park, MD 20740-3846; email: journal@aapm.org.

close