TUFGBRB03: Basis Vector Model Based Method for Proton Stopping Power Estimation From Experimental Dual Energy CT Data
Abstract
Purpose: This work aims at reducing the uncertainty in proton stopping power (SP) estimation by a novel combination of a linear, separable basis vector model (BVM) for stopping power calculation (Med Phys 43:600) and a statistical, modelbased dualenergy CT (DECT) image reconstruction algorithm (TMI 35:685). The method was applied to experimental data. Methods: BVM assumes the photon attenuation coefficients, electron densities, and mean excitation energies (Ivalues) of unknown materials can be approximated by a combination of the corresponding quantities of two reference materials. The DECT projection data for a phantom with 5 different known materials was collected on a Philips Brilliance scanner using two scans at 90 kVp and 140 kVp. The line integral alternating minimization (LIAM) algorithm was used to recover the two BVM coefficient images using the measured source spectra. The proton stopping powers are then estimated from the BetheBloch equation using electron densities and Ivalues derived from the BVM coefficients. The proton stopping powers and proton ranges for the phantom materials estimated via our BVM based DECT method are compared to ICRU reference values and a postprocessing DECT analysis (Yang PMB 55:1343) applied to vendorreconstructed images using the Torikoshi parametric fit model (tPFM). Results: For the phantommore »
 Authors:
 Washington University in St. Louis, St. Louis, MO (United States)
 Virginia Commonwealth University, Richmond, VA (United States)
 University of Pittsburgh, Pittsburgh, PA (United States)
 Publication Date:
 OSTI Identifier:
 22653996
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; ALGORITHMS; COMPUTERIZED TOMOGRAPHY; ELECTRON DENSITY; EXPERIMENTAL DATA; IMAGE PROCESSING; ITERATIVE METHODS; MEV RANGE 1001000; PHANTOMS; PROTONS; STOPPING POWER
Citation Formats
Zhang, S, Politte, D, O’Sullivan, J, Han, D, PorrasChaverri, M, Williamson, J, and Whiting, B. TUFGBRB03: Basis Vector Model Based Method for Proton Stopping Power Estimation From Experimental Dual Energy CT Data. United States: N. p., 2016.
Web. doi:10.1118/1.4957543.
Zhang, S, Politte, D, O’Sullivan, J, Han, D, PorrasChaverri, M, Williamson, J, & Whiting, B. TUFGBRB03: Basis Vector Model Based Method for Proton Stopping Power Estimation From Experimental Dual Energy CT Data. United States. doi:10.1118/1.4957543.
Zhang, S, Politte, D, O’Sullivan, J, Han, D, PorrasChaverri, M, Williamson, J, and Whiting, B. 2016.
"TUFGBRB03: Basis Vector Model Based Method for Proton Stopping Power Estimation From Experimental Dual Energy CT Data". United States.
doi:10.1118/1.4957543.
@article{osti_22653996,
title = {TUFGBRB03: Basis Vector Model Based Method for Proton Stopping Power Estimation From Experimental Dual Energy CT Data},
author = {Zhang, S and Politte, D and O’Sullivan, J and Han, D and PorrasChaverri, M and Williamson, J and Whiting, B},
abstractNote = {Purpose: This work aims at reducing the uncertainty in proton stopping power (SP) estimation by a novel combination of a linear, separable basis vector model (BVM) for stopping power calculation (Med Phys 43:600) and a statistical, modelbased dualenergy CT (DECT) image reconstruction algorithm (TMI 35:685). The method was applied to experimental data. Methods: BVM assumes the photon attenuation coefficients, electron densities, and mean excitation energies (Ivalues) of unknown materials can be approximated by a combination of the corresponding quantities of two reference materials. The DECT projection data for a phantom with 5 different known materials was collected on a Philips Brilliance scanner using two scans at 90 kVp and 140 kVp. The line integral alternating minimization (LIAM) algorithm was used to recover the two BVM coefficient images using the measured source spectra. The proton stopping powers are then estimated from the BetheBloch equation using electron densities and Ivalues derived from the BVM coefficients. The proton stopping powers and proton ranges for the phantom materials estimated via our BVM based DECT method are compared to ICRU reference values and a postprocessing DECT analysis (Yang PMB 55:1343) applied to vendorreconstructed images using the Torikoshi parametric fit model (tPFM). Results: For the phantom materials, the average stopping power estimations for 175 MeV protons derived from our method are within 1% of the ICRU reference values (except for Teflon with a 1.48% error), with an average standard deviation of 0.46% over pixels. The resultant proton ranges agree with the reference values within 2 mm. Conclusion: Our principled DECT iterative reconstruction algorithm, incorporating optimal beam hardening and scatter corrections, in conjunction with a simple linear BVM model, achieves more accurate and robust proton stopping power maps than the postprocessing, nonlinear tPFM based DECT analysis applied to conventional reconstructions of low and high energy scans. Funding Support: NIH R01CA 75371; NCI grant R01 CA 149305.},
doi = {10.1118/1.4957543},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = 2016,
month = 6
}

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WEDBRF05: Quantitative DualEnergy CT Imaging for Proton Stopping Power Computation
Purpose: To extend the twoparameter separable basisvector model (BVM) to estimation of proton stopping power from dualenergy CT (DECT) imaging. Methods: BVM assumes that the photon cross sections of any unknown material can be represented as a linear combination of the corresponding quantities for two bracketing basis materials. We show that both the electron density (ρe) and mean excitation energy (Iex) can be modeled by BVM, enabling stopping power to be estimated from the BetheBloch equation. We have implemented an idealized postprocessing dual energy imaging (pDECT) simulation consisting of monogenetic 45 keV and 80 keV scanning beams with polystyrenewater andmore » 
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Purpose: The conversion of Hounsfield Unit (HU) to proton stopping power ratio (SPR) is a main source of uncertainty in proton therapy. In this study, the SPRs of animal tissues were measured and compared with prediction from dual energy CT (DECT) and single energy CT (SECT) calibrations. Methods: A stoichiometric calibration method for DECT was applied to predict the SPR using CT images acquired at 80 kVp and 140 kVp. The dual energy index was derived based on the HUs of the paired spectral images and used to calculate the SPRs of the materials. Tissue surrogates with known chemical compositionsmore » 
Determination of lowenergy parameters of neutronproton scattering on the basis of modern experimental data from partialwave analyses
The triplet and singlet lowenergy parameters in the effectiverange expansion for neutronproton scattering are determined by using the latest experimental data on respective phase shifts from the SAID nucleonnucleon database. The results differ markedly from the analogous parameters obtained on the basis of the phase shifts of the Nijmegen group and contradict the parameter values that are presently used as experimental ones. The values found with the aid of the phase shifts from the SAID nucleonnucleon database for the total cross section for the scattering of zeroenergy neutrons by protons, {sigma}{sub 0} = 20.426 b, and the neutronproton coherent scatteringmore » 
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