First Investigation of List mode MLEM Reconstruction for Fast DC-SPECT System Design Optimization

Feng, Yuemeng; Blackberg, Lisa; Fakhri, Georges El; Worstell, W.; Sabet, Hamid

doi:10.1109/nss/mic44867.2021.9875864

Cited by 4 publications

(2 citation statements)

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“…We used 2 × 10 5 counts for the comparison between system matrix calculated by analytic modelling and by MC based methods. The system matrix calculated by Monte Carlo methods is based on the simulation, where measurements of detector to voxel response are required, one element in the system matrix is estimated by the possibility of one gamma photon emitted from voxel j being detected within one pixel i of the detector ( [25]). The analytic modelling is described in section 2.3.…”

Section: Resultsmentioning

confidence: 99%

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Resolution recovery on list mode MLEM reconstruction for dynamic cardiac SPECT system

Feng,

Worstell,

Kupinski

et al. 2023

Biomed. Phys. Eng. Express

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The Dynamic Cardiac SPECT (DC-SPECT) system is being developed at the Massachusetts General Hospital, featuring a static cardio focus asymmetrical geometry enabling simultaneous high-resolution and high-sensitivity imaging. Among 14 design iterations of the DC-SPECT with varying number of detector heads, system sensitivity and resolution, the current version under development features 10 mm FWHM geometrical resolution (without resolution recovery) and 0.07% sensitivity at the center of the FOV, this is 1.5× resolution gain and 7× sensitivity gain compared to a conventional dual head gamma camera (0.01% sensitivity and 15-mm resolution). This work presents improvement in imaging resolution by implementing a spatially variant point spread function (SV-PSF) with list mode MLEM reconstruction. A resolution recovery method by PSF deconvolution is validated on list mode MLEM reconstruction for the DC-SPECT. A spatial invariant PSF is included as an additional test to show the influence of the PSF modelling accuracy on reconstructed image quality. We compare the MLEM reconstruction with and without PSF deconvolution; an analytic model is used for the calculation of system response, and the results are compared to the reconstruction with system modelling using Monte Carlo (MC) based methods. Results show that with PSF modelling applied, the quality of the reconstructed image is improved, and the DC-SPECT system can achieve a 4.5 mm central spatial resolution with average 795 counts/Mbq. Both the SV-PSF and the spatial-invariant PSF improve the image quality, and the reconstruction with SV-PSF generates line profiles closer to the ground truth. The results show substantial improvement over the GE Discovery 570c performance (7 mm spatial resolution with an average 460 counts/MBq, 5.8 mm resolution at the FOV center). The impact of PSF deconvolution is significant, improvement of the reconstructed image quality is evident in comparison to MC simulated system matrix with the same sampling size in the simulation.

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Section: Resultsmentioning

confidence: 99%

“…The list mode MLEM reconstruction algorithm [25] aims to find l , j the mean number of photons emitted in voxel j, by iteratively calculating the sequence:…”

Section: List Mode Mlem With Image Based Psf Deconvolutionmentioning

confidence: 99%