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Title: Proton-induced x-ray fluorescence CT imaging

Abstract

Purpose: To demonstrate the feasibility of proton-induced x-ray fluorescence CT (pXFCT) imaging of gold in a small animal sized object by means of experiments and Monte Carlo (MC) simulations. Methods: First, proton-induced gold x-ray fluorescence (pXRF) was measured as a function of gold concentration. Vials of 2.2 cm in diameter filled with 0%–5% Au solutions were irradiated with a 220 MeV proton beam and x-ray fluorescence induced by the interaction of protons, and Au was detected with a 3 × 3 mm{sup 2} CdTe detector placed at 90° with respect to the incident proton beam at a distance of 45 cm from the vials. Second, a 7-cm diameter water phantom containing three 2.2-diameter vials with 3%–5% Au solutions was imaged with a 7-mm FWHM 220 MeV proton beam in a first generation CT scanning geometry. X-rays scattered perpendicular to the incident proton beam were acquired with the CdTe detector placed at 45 cm from the phantom positioned on a translation/rotation stage. Twenty one translational steps spaced by 3 mm at each of 36 projection angles spaced by 10° were acquired, and pXFCT images of the phantom were reconstructed with filtered back projection. A simplified geometry of the experimental data acquisitionmore » setup was modeled with the MC TOPAS code, and simulation results were compared to the experimental data. Results: A linear relationship between gold pXRF and gold concentration was observed in both experimental and MC simulation data (R{sup 2} > 0.99). All Au vials were apparent in the experimental and simulated pXFCT images. Specifically, the 3% Au vial was detectable in the experimental [contrast-to-noise ratio (CNR) = 5.8] and simulated (CNR = 11.5) pXFCT image. Due to fluorescence x-ray attenuation in the higher concentration vials, the 4% and 5% Au contrast were underestimated by 10% and 15%, respectively, in both the experimental and simulated pXFCT images. Conclusions: Proton-induced x-ray fluorescence CT imaging of 3%–5% gold solutions in a small animal sized water phantom has been demonstrated for the first time by means of experiments and MC simulations.« less

Authors:
;  [1];  [2]; ; ; ;  [3];  [4];  [5]
  1. Department of Radiation Oncology, Stanford University, Stanford, California 94305-5847 and Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo 060-8648 (Japan)
  2. Department of Radiation Oncology, Stanford University, Stanford, California 94305-5847 (United States)
  3. Department of Medical Physics, Proton Beam Therapy Center, Hokkaido University Hospital, Sapporo 060-8648, Japan and Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo 060-8648 (Japan)
  4. Department of Medical Physics, Proton Beam Therapy Center, Hokkaido University Hospital, Sapporo 060-8648 (Japan)
  5. Department of Radiology, Stanford University, Stanford, California 94305 (United States)
Publication Date:
OSTI Identifier:
22413451
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 42; Journal Issue: 2; Other Information: (c) 2015 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 60 APPLIED LIFE SCIENCES; CAT SCANNING; CDTE SEMICONDUCTOR DETECTORS; FLUORESCENCE; MONTE CARLO METHOD; NOISE; PHANTOMS; PROTON BEAMS; X RADIATION

Citation Formats

Bazalova-Carter, Magdalena, E-mail: bazalova@stanford.edu, Xing, Lei, Ahmad, Moiz, Matsuura, Taeko, Takao, Seishin, Shirato, Hiroki, Umegaki, Kikuo, Matsuo, Yuto, and Fahrig, Rebecca. Proton-induced x-ray fluorescence CT imaging. United States: N. p., 2015. Web. doi:10.1118/1.4906169.
Bazalova-Carter, Magdalena, E-mail: bazalova@stanford.edu, Xing, Lei, Ahmad, Moiz, Matsuura, Taeko, Takao, Seishin, Shirato, Hiroki, Umegaki, Kikuo, Matsuo, Yuto, & Fahrig, Rebecca. Proton-induced x-ray fluorescence CT imaging. United States. doi:10.1118/1.4906169.
Bazalova-Carter, Magdalena, E-mail: bazalova@stanford.edu, Xing, Lei, Ahmad, Moiz, Matsuura, Taeko, Takao, Seishin, Shirato, Hiroki, Umegaki, Kikuo, Matsuo, Yuto, and Fahrig, Rebecca. Sun . "Proton-induced x-ray fluorescence CT imaging". United States. doi:10.1118/1.4906169.
@article{osti_22413451,
title = {Proton-induced x-ray fluorescence CT imaging},
author = {Bazalova-Carter, Magdalena, E-mail: bazalova@stanford.edu and Xing, Lei and Ahmad, Moiz and Matsuura, Taeko and Takao, Seishin and Shirato, Hiroki and Umegaki, Kikuo and Matsuo, Yuto and Fahrig, Rebecca},
abstractNote = {Purpose: To demonstrate the feasibility of proton-induced x-ray fluorescence CT (pXFCT) imaging of gold in a small animal sized object by means of experiments and Monte Carlo (MC) simulations. Methods: First, proton-induced gold x-ray fluorescence (pXRF) was measured as a function of gold concentration. Vials of 2.2 cm in diameter filled with 0%–5% Au solutions were irradiated with a 220 MeV proton beam and x-ray fluorescence induced by the interaction of protons, and Au was detected with a 3 × 3 mm{sup 2} CdTe detector placed at 90° with respect to the incident proton beam at a distance of 45 cm from the vials. Second, a 7-cm diameter water phantom containing three 2.2-diameter vials with 3%–5% Au solutions was imaged with a 7-mm FWHM 220 MeV proton beam in a first generation CT scanning geometry. X-rays scattered perpendicular to the incident proton beam were acquired with the CdTe detector placed at 45 cm from the phantom positioned on a translation/rotation stage. Twenty one translational steps spaced by 3 mm at each of 36 projection angles spaced by 10° were acquired, and pXFCT images of the phantom were reconstructed with filtered back projection. A simplified geometry of the experimental data acquisition setup was modeled with the MC TOPAS code, and simulation results were compared to the experimental data. Results: A linear relationship between gold pXRF and gold concentration was observed in both experimental and MC simulation data (R{sup 2} > 0.99). All Au vials were apparent in the experimental and simulated pXFCT images. Specifically, the 3% Au vial was detectable in the experimental [contrast-to-noise ratio (CNR) = 5.8] and simulated (CNR = 11.5) pXFCT image. Due to fluorescence x-ray attenuation in the higher concentration vials, the 4% and 5% Au contrast were underestimated by 10% and 15%, respectively, in both the experimental and simulated pXFCT images. Conclusions: Proton-induced x-ray fluorescence CT imaging of 3%–5% gold solutions in a small animal sized water phantom has been demonstrated for the first time by means of experiments and MC simulations.},
doi = {10.1118/1.4906169},
journal = {Medical Physics},
number = 2,
volume = 42,
place = {United States},
year = {Sun Feb 15 00:00:00 EST 2015},
month = {Sun Feb 15 00:00:00 EST 2015}
}