A wide-acceptance Compton spectrometer for spectral characterization of a medical x-ray source

Michelle A. Espy; A. Gehring; A. Belian; T. Haines; J. Hunter; M. James; M. Klasky; J. Mendez; D. Moir; R. Sedillo; R. Shurter; J. Stearns; K. Van Syoc; P. Volegov

doi:10.1117/12.2216269

22 March 2016 A wide-acceptance Compton spectrometer for spectral characterization of a medical x-ray source

Michelle A. Espy, A. Gehring, A. Belian, T. Haines, J. Hunter, M. James, M. Klasky, J. Mendez, D. Moir, R. Sedillo, R. Shurter, J. Stearns, K. Van Syoc, P. Volegov

Author Affiliations +

Proceedings Volume 9783, Medical Imaging 2016: Physics of Medical Imaging; 97834V (2016) https://doi.org/10.1117/12.2216269
Event: SPIE Medical Imaging, 2016, San Diego, California, United States

Abstract

Accurate knowledge of the x-ray spectra used in medical treatment and radiography is important for dose calculations and material decomposition analysis. Indirect measurements via transmission through materials are possible. However, such spectra are challenging to measure directly due to the high photon fluxes. One method of direct measurement is via a Compton spectrometer (CS) method. In this approach, the x-rays are converted to a much lower flux of electrons via Compton scattering on a converter foil (typically beryllium or aluminum). The electrons are then momentum selected by bending in a magnetic field. With tight angular acceptance of electrons into the magnet of ~ 1 deg, there is a linear correlation between incident photon energy and electron position recorded on an image plate. Here we present measurements of Bremsstrahlung spectrum from a medical therapy machine, a Scanditronix M22 Microtron. Spectra with energy endpoints from 6 to 20 MeV are directly measured, using a CS with a wide energy range from 0.5 to 20 MeV. We discuss the sensitivity of the device and the effects of converter material and collimation on the accuracy of the reconstructed spectra. Approaches toward improving the sensitivity, including the use of coded apertures, and potential future applications to characterization of spectra are also discussed.

Citation Download Citation

Michelle A. Espy, A. Gehring, A. Belian, T. Haines, J. Hunter, M. James, M. Klasky, J. Mendez, D. Moir, R. Sedillo, R. Shurter, J. Stearns, K. Van Syoc, and P. Volegov "A wide-acceptance Compton spectrometer for spectral characterization of a medical x-ray source", Proc. SPIE 9783, Medical Imaging 2016: Physics of Medical Imaging, 97834V (22 March 2016); https://doi.org/10.1117/12.2216269

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available