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Title: SU-G-IeP2-09: Iodine Imaging at Spectral CT with a Dual-Layer Detector

Abstract

Purpose: To evaluate the attenuation response of iodine and the accuracy of iodine quantification on a detector-based spectral CT scanner. Methods: A Gammex 461A phantom was scanned using a dual-layer detector (IQon, Philips) at 120 kVp using helical acquisition with a CDTIvol of 15 mGy to approximate the hospital’s clinical body protocol. No modifications to the standard protocol were necessary to enable spectral imaging. Iodine inserts at 6 concentrations (2, 5, 7.5, 10, 15, 20 mg/ml) were scanned individually at the center of the phantom and the 20 mg/ml insert was additionally scanned at the 3, 6, and 12 o’clock positions. Scans were repeated 10 times. Conventional, virtual monoenergetic (40–200 keV) and iodine-no-water images (with pixel values equal to iodine concentration of corresponding tissue) were reconstructed from acquired data. A circular ROI (diameter=30 pixels) was used in each conventional and monoenergetic image to measure the mean and standard deviation of the CT number in HU and in each iodine-no-water image to measure iodine concentration in mg/ml. Results: Mean CT number and contrast-to-noise ratio (CNR) measured from monoenergetic images increased with decreasing keV for all iodine concentrations and matched measurements from conventional images at 75 keV. Measurements from the 20 mlmore » insert showed the CT number is independent of location and CNR is a function only of noise, which was higher in the center. Measured concentration from iodine-no-water images matched phantom manufacturer suggested concentration to within 6% on average for inserts at the center of the phantom. Measured concentrations were systematically higher due to optimization of iodine quantification parameters for clinical mixtures of iodine and blood/tissue. Conclusion: Spectral acquisition and reconstruction with a dual-layer detector represents the physical behavior of iodine as expected and accurately quantifies the material concentration. This should permit a variety of clinical applications including lesion characterization, vessel patency, and myocardial perfusion. This study was performed as part of a research agreement among Philips Healthcare, University Hospitals of Cleveland, and Case Western Reserve University.« less

Authors:
 [1]; ; ;  [2];  [3];  [4]
  1. Case Western Reserve University, Cleveland, Ohio (United States)
  2. Philips Healthcare, Highland Heights, OH (United States)
  3. The University of Texas at Austin, Austin, TX (United States)
  4. University Hospitals Case Medical Center, Cleveland, OH (United States)
Publication Date:
OSTI Identifier:
22649361
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; BIOMEDICAL RADIOGRAPHY; COMPUTERIZED TOMOGRAPHY; CONCENTRATION RATIO; ECOLOGICAL CONCENTRATION; EDUCATIONAL FACILITIES; IMAGES; IODINE; KEV RANGE 100-1000; KEV RANGE 10-100; PHANTOMS

Citation Formats

Ozguner, O, Dhanantwari, A, Halliburton, S, Utrup, S, Wen, G, and Jordan, D. SU-G-IeP2-09: Iodine Imaging at Spectral CT with a Dual-Layer Detector. United States: N. p., 2016. Web. doi:10.1118/1.4957014.
Ozguner, O, Dhanantwari, A, Halliburton, S, Utrup, S, Wen, G, & Jordan, D. SU-G-IeP2-09: Iodine Imaging at Spectral CT with a Dual-Layer Detector. United States. doi:10.1118/1.4957014.
Ozguner, O, Dhanantwari, A, Halliburton, S, Utrup, S, Wen, G, and Jordan, D. Wed . "SU-G-IeP2-09: Iodine Imaging at Spectral CT with a Dual-Layer Detector". United States. doi:10.1118/1.4957014.
@article{osti_22649361,
title = {SU-G-IeP2-09: Iodine Imaging at Spectral CT with a Dual-Layer Detector},
author = {Ozguner, O and Dhanantwari, A and Halliburton, S and Utrup, S and Wen, G and Jordan, D},
abstractNote = {Purpose: To evaluate the attenuation response of iodine and the accuracy of iodine quantification on a detector-based spectral CT scanner. Methods: A Gammex 461A phantom was scanned using a dual-layer detector (IQon, Philips) at 120 kVp using helical acquisition with a CDTIvol of 15 mGy to approximate the hospital’s clinical body protocol. No modifications to the standard protocol were necessary to enable spectral imaging. Iodine inserts at 6 concentrations (2, 5, 7.5, 10, 15, 20 mg/ml) were scanned individually at the center of the phantom and the 20 mg/ml insert was additionally scanned at the 3, 6, and 12 o’clock positions. Scans were repeated 10 times. Conventional, virtual monoenergetic (40–200 keV) and iodine-no-water images (with pixel values equal to iodine concentration of corresponding tissue) were reconstructed from acquired data. A circular ROI (diameter=30 pixels) was used in each conventional and monoenergetic image to measure the mean and standard deviation of the CT number in HU and in each iodine-no-water image to measure iodine concentration in mg/ml. Results: Mean CT number and contrast-to-noise ratio (CNR) measured from monoenergetic images increased with decreasing keV for all iodine concentrations and matched measurements from conventional images at 75 keV. Measurements from the 20 ml insert showed the CT number is independent of location and CNR is a function only of noise, which was higher in the center. Measured concentration from iodine-no-water images matched phantom manufacturer suggested concentration to within 6% on average for inserts at the center of the phantom. Measured concentrations were systematically higher due to optimization of iodine quantification parameters for clinical mixtures of iodine and blood/tissue. Conclusion: Spectral acquisition and reconstruction with a dual-layer detector represents the physical behavior of iodine as expected and accurately quantifies the material concentration. This should permit a variety of clinical applications including lesion characterization, vessel patency, and myocardial perfusion. This study was performed as part of a research agreement among Philips Healthcare, University Hospitals of Cleveland, and Case Western Reserve University.},
doi = {10.1118/1.4957014},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}