PMID: 9167160May 1, 1997Paper

Estimation of a photon energy spectrum for a computed tomography scanner

Medical Physics
C Ruth, P M Joseph

Abstract

Estimated photon energy spectra are derived from transmission measurements using aluminium, copper, and sodium iodide absorbers. Two spectral models are proposed. One is based on a previously published model that analyzes the electron's penetration into the anode, and the production and attenuation of bremsstrahlung photons. The second model does not include details regarding the underlying physics, but treats the spectrum as a sum of delta functions. A nonlinear regularization method is used to overcome ill conditioning in the second model. Both models fit the transmission data to an accuracy of 0.30%, which is consistent with the experimental error. A quantitative comparison of the models is made by calculating the average and variance (over the derived energy spectra) of several relevant mass attenuation coefficients. The maximum variation in the average and variance was 1.5% and 3.2%, respectively, indicating that the spectra exhibit similar attenuation and beam hardening properties. The spectra were tested with a simulation that predicts scanner CT numbers for phantom measurements consisting of dilutions of sodium iodide in a water equivalent background. The agreement between simulation and experiment ranged from 1.5% at 2...Continue Reading

References

Jan 1, 1978·Journal of Computer Assisted Tomography·P M Joseph, R D Spital
Oct 1, 1976·Computers in Biology and Medicine·G T HermanA Naparstek
May 1, 1992·Medical Physics·J P Bissonnette, L J Schreiner
Mar 1, 1991·Medical Physics·D M TuckerD P Chakraborty
May 1, 1981·Medical Physics·L C Baird

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Citations

Jul 1, 2010·Tsinghua Science and Technology·Seungryong ChoXiaochuan Pan
Nov 26, 2009·Medical Physics·B Heismann, M Balda
Oct 1, 2010·Medical Physics·Ernesto AmatoIgnazio Pandolfo
Apr 2, 2011·Medical Physics·Xinhui DuanCynthia H McCollough
Feb 19, 2016·Journal of X-ray Science and Technology·Qingsong YangGe Wang
May 8, 2014·IEEE Transactions on Medical Imaging·Yong Long, Jeffrey A Fessler
Apr 2, 2009·IEEE Transactions on Medical Imaging·Joonki NohPaul E Kinahan
Jul 11, 2006·IEEE Transactions on Medical Imaging·Wojciech Zbijewski, Freek J Beekman
Aug 6, 1999·Medical Physics·R G WaggenerW D McDavid
Feb 24, 2001·Medical Physics·J R MercierD M Tucker
Oct 29, 2004·Physics in Medicine and Biology·A P ColijnF J Beekman
Sep 12, 2002·Physics in Medicine and Biology·P HomolkaR Nowotny
Dec 20, 2013·Physics in Medicine and Biology·Sarah E McKenneyJohn M Boone

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