Evaluation of various energy windows at different radionuclides for scatter and attenuation correction in nuclear medicine

Asgari, Afrouz; Ashoor, Mansour; Sohrabpour, M.; Shokrani, Parvaneh; Rezaei, Ali

doi:10.1007/s12149-015-0950-1

Cited by 12 publications

(8 citation statements)

References 14 publications

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“…A previous study[ 12 ] has assessed the TEW method for Sm-153 SPECT data. But until now, no study has compared the fraction of scattered photons of Sm-153 with varying main- and sub-energy windows for the implementation of the TEW method.…”

Section: Discussionmentioning

confidence: 99%

“…The quantification of gamma-camera imaging is improved after the correction of scattered radiation. Previous works[ 6 7 8 9 10 11 12 13 14 15 16 17 ] were used triple-energy window (TEW) scatter correction to eliminate the detected scattered counts inside energy window. In order to quantify emission from the isotope Sm-153 using a gamma-camera accurately, however, it is important to correct the scattered photons which degrade image quality.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of scatter correction method in samarium-153 single-photon emission computed tomography using triple-energy window: A monte carlo simulation study

et al. 2020

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Purpose: In single-photon emission computed tomography imaging, the presence of scatter degrades image quality. The goal of this study is to optimize the main- and sub-energy windows for triple-energy window (TEW) method using Monte Carlo SImulating Medical Imaging Nuclear Detectors (SIMIND) code for samarium-153 (Sm-153) imaging. Materials and Methods: The comparison is based on the Monte Carlo simulation data with the results estimated using TEW method. Siemens Symbia gamma-camera equipped with low-energy high-resolution collimator was simulated for Sm-153 point source located in seven positions in water cylindrical phantom. Three different main-energy window widths (10%, 15%, and 20%) and three different sub-energy window widths (2, 4, and 6 keV) were evaluated. We compared the true scatter fraction determined by SIMIND and scatter fraction estimated using TEW scatter correction method at each position. In order to evaluate the image quality, we used the full width at half maximum (FWHM) computed on the PSF and image contrast using Jaszczak phantom. Results: The scatter fraction using TEW method is similar to the true scatter fraction for 20% of the main-energy window and 6 keV sub-energy windows. For these windows, the results show that the resolution and contrast were improved. Conclusion: TEW method could be a useful scatter correction method to remove the scatter event in the image for Sm-153 imaging.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimization of scatter correction method in samarium-153 single-photon emission computed tomography using triple-energy window: A monte carlo simulation study

et al. 2020

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“…However, differences in methods of scatter correction and among conditions such as the width of sub-energy windows can lead to over- or under-correction that increases image noise and results in poor quantitation [ 26 ]. The appropriate determination of sub-energy window width on energy spectra should be optimal to improve bone SPECT image quality and quantitative accuracy [ 27 ]. Moreover, effective scatter source estimation (ESSE) is combined with measured transmission data for commercial scatter correction [ 28 ].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of quantitative accuracy among different scatter corrections for quantitative bone SPECT/CT imaging

et al. 2022

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Although scatter correction improves SPECT image contrast and thus image quality, the effects of quantitation accuracy under various conditions remain unclear. The present study aimed to empirically define the conditions for the optimal scatter correction of quantitative bone SPECT/CT images. Scatter correction was performed by applying dual and triple energy windows (DEW and TEW) with different sub-energy window widths, and effective scatter source estimation (ESSE) to CT-based scatter correction. Scattered radiation was corrected on images acquired using a triple line source (TLSP) phantom and an uniform cylinder phantom. The TLSP consisted of a line source containing 74.0 MBq of 99mTc in the middle, and a background component containing air, water or a K2HPO4 solution with a density equivalent to that of bone. The sum of all pixels in air, water and the K2HPO4 solution was measured on SPECT images. Scatter fraction (SF) and normalized mean square error (NMSE) based on counts from the air background as a reference were then calculated to assess quantitative errors due to scatter correction. The uniform cylinder phantom contained the same K2HPO4 solution and 222.0 MBq of 99mTc. The coefficient of variation (CV) was calculated from the count profile of this phantom to assess the uniformity of SPECT images across scatter correction under various conditions. Both SF and NMSE in SPECT images of phantoms containing water in the background were lower at a TEW sub-window of 3% (TEW3%), than in other scatter corrections, whereas those in K2HPO4 were lower at a DEW sub-window of 20% (DEW20%). Larger DEW and smaller TEW sub-energy windows allowed more effective correction. The CV of the uniform cylinder phantom, DEW20%, was inferior to all other tested scatter corrections. The quantitative accuracy of bone SPECT images substantially differed according to the method of scatter correction. The optimal scatter correction for quantitative bone SPECT was DEW20% (k = 1), but at the cost of slightly decreased image uniformity.

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“…Consequently, the FWHM value increases and the image resolution deteriorates. Much effort has been executed to raise the PCs sensitivity without deteriorating the resolution, or vice versa, via representing novel plans and optimizing the geometric configurations of collimator [4][5][6][7][8][9][10]. One of the most significant difficulties collaborated with the PCs is compromise between sensitivity and resolution [11] that this problem has been roughly solved by extended parallel hole collimators (EPCs).…”

Section: Introductionmentioning

confidence: 99%

Improvement of the Point Spread Function by Collimators’ New Configuration in Nuclear Medicine

Ashoor

Khorshidi

2021

Preprint

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Objective: The collimators in which the various geometrical configurations have been suggested to optimize the sensitivity and resolution have a key role in acquiring the qualified images in nuclear medicine towards a better recognition of some diseases. Methods: In this study, a new configuration as a geometrical combination of the conical, cylindrical and spherical (CCS) volumes for parallel hole collimators which is assessed by using the volumetric-parametric method has been introduced to improve point spread function (PSF) being the collimators response on the radioactive point source. It has been simulated by the MCNPX code at the various energies values of the point source along with the traditional collimator in which included the cylindrical volume only. Results: The PSF will transmogrify from a delta function to a distribution which can correlate with a Gaussian distribution, while the scattered gamma rays were increased. The simulation results have indicated that the PSF in the CCS configuration is narrower than that of the cylindrical one at all the energies, leading the improvement of the resolution. Also, the theoretical results are agreement with the simulated ones. The more the energy value of the source, the more broaden the PSF will be due the more penetration strength. The narrower the PSF, the better the qualified image will be. Conclusion: This method may be employed to determine the accurate attenuation coefficient of absorbers as well.

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Evaluation of various energy windows at different radionuclides for scatter and attenuation correction in nuclear medicine

Cited by 12 publications

References 14 publications

Optimization of scatter correction method in samarium-153 single-photon emission computed tomography using triple-energy window: A monte carlo simulation study

Optimization of scatter correction method in samarium-153 single-photon emission computed tomography using triple-energy window: A monte carlo simulation study

Evaluation of quantitative accuracy among different scatter corrections for quantitative bone SPECT/CT imaging

Improvement of the Point Spread Function by Collimators’ New Configuration in Nuclear Medicine

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