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On-board SPECT for localizing functional targets: a simulation study.

Publication ,  Journal Article
Roper, J; Bowsher, J; Yin, F-F
Published in: Med Phys
May 2009

Single photon emission computed tomography (SPECT) was investigated for imaging on-board radiation therapy machines in order to localize functional and molecular targets. A computer-simulated female NCAT phantom was positioned supine on a flat-top treatment couch. Twenty tumor locations were defined in the upper torso. The eight lung tumors were subject to the effects of respiratory motion. Tumor diameters of 10.8, 14.4, and 21.6 mm were simulated for tumor-to-background ratios of 3:1 and 6:1 that are characteristic of the radiotracer 99mTc-sestamibi. Projection images representing scan times of 4, 8, and 20 min were simulated for an anterior, half-circular trajectory. Images were reconstructed with attenuation correction by ordered-subsets expectation maximization (OSEM) using six subsets and five iterations. Contrast-to-noise ratios (CNRs) were calculated from ensembles of 25 images. Cross correlation with a noise-free tumor template was used to select the most suspicious tumor location within a 14.4-mm-radius search volume surrounding each tumor, with only that one tumor in each search volume. Localization accuracy was assessed by calculating average distances between measured and true tumor locations. Localization accuracy and CNRs were strongly affected by tumor location relative to the detector trajectory. For example, CNR values near the chest wall were greater by a factor of 3.5 than for tumors near the spine and posterior ribs, a much greater effect than the factor of 1.6 difference in CNR between 6:1 and 3:1 tumor uptakes. Typically, tumors of 6:1 uptake were localized as accurately with 4 min of scan time as tumors of 3:1 uptake that had been imaged for 20 min. Using 4 min scans, 14.4 and 21.6 mm anterior tumors of 6:1 uptake were localized within 2 mm. These results suggest that SPECT, on-board radiation therapy machines, may be a viable modality for localizing certain functional and molecular targets using relatively short scan times.

Duke Scholars

Published In

Med Phys

DOI

ISSN

0094-2405

Publication Date

May 2009

Volume

36

Issue

5

Start / End Page

1727 / 1735

Location

United States

Related Subject Headings

  • Tomography, Emission-Computed, Single-Photon
  • Sensitivity and Specificity
  • Reproducibility of Results
  • Phantoms, Imaging
  • Pattern Recognition, Automated
  • Nuclear Medicine & Medical Imaging
  • Image Interpretation, Computer-Assisted
  • Image Enhancement
  • Humans
  • Female
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Roper, J., Bowsher, J., & Yin, F.-F. (2009). On-board SPECT for localizing functional targets: a simulation study. Med Phys, 36(5), 1727–1735. https://doi.org/10.1118/1.3113902
Roper, Justin, James Bowsher, and Fang-Fang Yin. “On-board SPECT for localizing functional targets: a simulation study.Med Phys 36, no. 5 (May 2009): 1727–35. https://doi.org/10.1118/1.3113902.
Roper J, Bowsher J, Yin F-F. On-board SPECT for localizing functional targets: a simulation study. Med Phys. 2009 May;36(5):1727–35.
Roper, Justin, et al. “On-board SPECT for localizing functional targets: a simulation study.Med Phys, vol. 36, no. 5, May 2009, pp. 1727–35. Pubmed, doi:10.1118/1.3113902.
Roper J, Bowsher J, Yin F-F. On-board SPECT for localizing functional targets: a simulation study. Med Phys. 2009 May;36(5):1727–1735.

Published In

Med Phys

DOI

ISSN

0094-2405

Publication Date

May 2009

Volume

36

Issue

5

Start / End Page

1727 / 1735

Location

United States

Related Subject Headings

  • Tomography, Emission-Computed, Single-Photon
  • Sensitivity and Specificity
  • Reproducibility of Results
  • Phantoms, Imaging
  • Pattern Recognition, Automated
  • Nuclear Medicine & Medical Imaging
  • Image Interpretation, Computer-Assisted
  • Image Enhancement
  • Humans
  • Female