Advanced

Patient-Specific Whole-Body Attenuation Correction Maps from a CT System for Conjugate-View-Based Activity Quantification: Method Development and Evaluation.

Sjögreen Gleisner, Katarina LU and Ljungberg, Michael LU (2012) In Cancer Biotherapy & Radiopharmaceuticals 27(10). p.652-664
Abstract
Abstract For activity quantification based on planar scintillation camera measurements, photon attenuation is an important factor that needs to be corrected for in a patient- and organ-specific manner. One possibility for obtaining attenuation correction maps is to use X-ray CT scout images. Since the intensity of scout images is in relative numbers, their image values need to be multiplied by a factor to become quantitative and thus useful for attenuation correction. The calibration factor can for our current imaging system be obtained from a scanner system file, but is generally not available. For this purpose, a method based on the patient weight has been developed. Results based on 79 patient scout images show that the calibration... (More)
Abstract For activity quantification based on planar scintillation camera measurements, photon attenuation is an important factor that needs to be corrected for in a patient- and organ-specific manner. One possibility for obtaining attenuation correction maps is to use X-ray CT scout images. Since the intensity of scout images is in relative numbers, their image values need to be multiplied by a factor to become quantitative and thus useful for attenuation correction. The calibration factor can for our current imaging system be obtained from a scanner system file, but is generally not available. For this purpose, a method based on the patient weight has been developed. Results based on 79 patient scout images show that the calibration factor thus determined correlates well with values that, in this case, are independently specified by the system. The accuracy of attenuation correction factors (ACFs) derived from the scout-based attenuation correction maps is evaluated by comparison to ACFs derived from three-dimensional CT studies. For photon energies of 208, 245, and 364 keV, scout-based ACFs are on average 1.2% and 0.5% from the CT-derived values, using the system-based and the weight-based values of the scout-image calibration factor, respectively. The imprecision is somewhat higher for the weight-based method, due to variability in the delineation of the patient contour used as a part of this method. In conclusion, X-ray scouts are found useful for attenuation correction with a satisfactory accuracy obtained, both using the new, weight-based method, and using the previous, system-based method, for determining the required calibration factor. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Cancer Biotherapy & Radiopharmaceuticals
volume
27
issue
10
pages
652 - 664
publisher
Mary Ann Liebert, Inc.
external identifiers
  • wos:000311959100003
  • pmid:23210927
  • scopus:84870797284
ISSN
1557-8852
DOI
10.1089/cbr.2011.1082
language
English
LU publication?
yes
id
ff5443fb-71ed-4b9c-ba48-10c2c2a81297 (old id 3347648)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/23210927?dopt=Abstract
date added to LUP
2013-01-02 11:14:59
date last changed
2017-01-01 05:31:14
@article{ff5443fb-71ed-4b9c-ba48-10c2c2a81297,
  abstract     = {Abstract For activity quantification based on planar scintillation camera measurements, photon attenuation is an important factor that needs to be corrected for in a patient- and organ-specific manner. One possibility for obtaining attenuation correction maps is to use X-ray CT scout images. Since the intensity of scout images is in relative numbers, their image values need to be multiplied by a factor to become quantitative and thus useful for attenuation correction. The calibration factor can for our current imaging system be obtained from a scanner system file, but is generally not available. For this purpose, a method based on the patient weight has been developed. Results based on 79 patient scout images show that the calibration factor thus determined correlates well with values that, in this case, are independently specified by the system. The accuracy of attenuation correction factors (ACFs) derived from the scout-based attenuation correction maps is evaluated by comparison to ACFs derived from three-dimensional CT studies. For photon energies of 208, 245, and 364 keV, scout-based ACFs are on average 1.2% and 0.5% from the CT-derived values, using the system-based and the weight-based values of the scout-image calibration factor, respectively. The imprecision is somewhat higher for the weight-based method, due to variability in the delineation of the patient contour used as a part of this method. In conclusion, X-ray scouts are found useful for attenuation correction with a satisfactory accuracy obtained, both using the new, weight-based method, and using the previous, system-based method, for determining the required calibration factor.},
  author       = {Sjögreen Gleisner, Katarina and Ljungberg, Michael},
  issn         = {1557-8852},
  language     = {eng},
  number       = {10},
  pages        = {652--664},
  publisher    = {Mary Ann Liebert, Inc.},
  series       = {Cancer Biotherapy & Radiopharmaceuticals},
  title        = {Patient-Specific Whole-Body Attenuation Correction Maps from a CT System for Conjugate-View-Based Activity Quantification: Method Development and Evaluation.},
  url          = {http://dx.doi.org/10.1089/cbr.2011.1082},
  volume       = {27},
  year         = {2012},
}