Collimator-detector response compensation in molecular SPECT reconstruction using STIR framework

Authors

  • Gholamreza Raisali Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
  • Hojjat Mahani Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran|Research Center for Molecular and Cellular Imaging, Tehran University of Medical Science, Tehran, Iran
  • Mohammad Reza Ay Research Center for Molecular and Cellular Imaging, Tehran University of Medical Science, Tehran, Iran |Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Science, Tehran, Iran
Abstract:

Introduction:It is well-recognized that collimator-detector response (CDR) is the main image blurring factor in SPECT.  In this research, we compensated the images for CDR in molecular SPECT by using STIR reconstruction framework. Methods: To assess resolution recovery capability of the STIR, a phantom containing five point sources along with a micro Derenzo phantom were investigated. Influence of the lesion size on SPECT quantification was addressed by calculating recovery coefficients (RCs) as well as spill-over ratios (SORs) for reconstructed NEMA image-quality phantom. Impact of the resolution modeling on noise properties was also studied. The RCs were then compared with those of experimentally obtained. In all cases, the images were iteratively reconstructed using an OSEM algorithm with 4 subsets and 32 subiterations. Results: CDR compensation gives rise to a significant drop in tomographic resolution from 2.45 mm to 1.55 mm. RC for hot rods of the NEMA IQ phantom monotonically grows as rod diameter increases, and results in an improvement of the RC up to a factor of 1.24 for the 5-mm rod diameter. PSF modeling also leads to a reduction in SOR from 0.24 to 0.16 averaged for the two cold cylinders. As a consequence of resolution recovery, a 15.5% overshoot near sharp edges imposing Gibbs ringing artifact occurs. In addition, a blobby noise texture is also observed. Furthermore, STIR results are consistent with the experimental ones. Conclusion: Our findings demonstrate that resolution recovery is required for quantitative molecular SPECT imaging, and CDR compensation by the STIR framework offers superior SPECT image quality.

Upgrade to premium to download articles

Sign up to access the full text

Already have an account?login

similar resources

collimator-detector response compensation in molecular spect reconstruction using stir framework

introduction:it is well-recognized that collimator-detector response (cdr) is the main image blurring factor in spect.  in this research, we compensated the images for cdr in molecular spect by using stir reconstruction framework. methods: to assess resolution recovery capability of the stir, a phantom containing five point sources along with a micro derenzo phantom were investigated. influence...

full text

Simultaneous compensation for attenuation, scatter and detector response for SPECT reconstruction in three dimensions.

A three-dimensional reconstruction method for simultaneous compensation of attenuation, scatter and distance-dependent detector response for single photon emission computed tomography is described and tested by experimental studies. The method determines the attenuation factors recursively along each projection ray starting at the intersected source voxel closest to the detector. The method sub...

full text

CdZnTe strip detector SPECT imaging with a slit collimator.

In this paper, we propose a CdZnTe rotating and spinning gamma camera attached with a slit collimator. This imaging system acquires convergent planar integrals of a radioactive distribution. Two analytical image reconstruction algorithms are proposed. Preliminary phantom studies show that our small CdZnTe camera with a slit collimator outperforms a larger NaI(Tl) camera with a pinhole collimato...

full text

Reduction of Collimator Correction Artefacts with Bayesian Reconstruction in Spect

Poor resolution of single photon emission computed tomography (SPECT) has degraded its use in clinical practice. Collimator correction has been shown to improve the reconstructed resolution, but the correction can generate ringing artefacts, which lower image quality. This paper investigates whether Bayesian reconstruction methods could reduce these artefacts. We have applied and tested three B...

full text

Development of a collimator blurring compensation method using fine angular sampling projection data in SPECT.

Due to the collimator aperture, spatial resolution of SPECT data varies with source-to-detector distance. Since the radius of detector rotation is bigger when scanning larger patients, spatial resolution is degraded in these cases. Emitted gamma rays travel not only along the central axis of the collimator hole but also off-axis due to the collimator aperture. However, an off-axis ray at one an...

full text

My Resources

Save resource for easier access later

Save to my library Already added to my library

{@ msg_add @}


Journal title

volume 25  issue Supplement 1

pages  26- 34

publication date 2017-02-01

By following a journal you will be notified via email when a new issue of this journal is published.

Hosted on Doprax cloud platform doprax.com

copyright © 2015-2023