Attenuation map estimation with SPECT emission data only

Yan, Yan; Zeng, G.L.

doi:10.1002/ima.20200

Cited by 14 publications

(11 citation statements)

References 25 publications

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“…Although each of the proposed methods has been somewhat successful, the attenuation problem is still not fully solved, and therefore, due to attenuation, the use of quantitative methods in SPECT is difficult. [ 14 15 23 ]…”

Section: Discussionmentioning

confidence: 99%

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Attenuation correction in single-photon emission computed tomography for NURBS-based cardiac-torso phantom using dual-energy acquisition

et al. 2020

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Single photon emission tomography is widely used to detect photons emitted from the patient. Some of these emitted photons suffer from scattering and absorption because of the attenuation occurred through their path in patient's body. Therefore, the attenuation is the most important problem in single-photon emission computed tomography (SPECT) imaging. Some of the radioisotopes emit gamma rays in different energy levels, and consequently, they have different counts and attenuation coefficients. Calculation of the parameters used in the attenuation equation Nout=αNin= e− μ l Ninby mathematical methods is useful for the attenuation correction. Nurbs-based cardiac-torso (NCAT) phantom with an adequate attenuation coefficient and activity distribution is used in this study. Simulations were done using SimSET in 20—70 and 20—167 keV. A total of 128 projections were acquired over 360°. The corrected and reference images were compared using a universal image quality index (UIQI). The simulation repeated using NCAT phantom by SimSET. In the first group, no attenuation correction was used, but the Zubal coefficients were used for attenuation correction in the second image group. After the image reconstruction, a comparison between image groups was done using optimized UIQI to determine the quality of used reconstruction methods. Similarities of images were investigated by considering the average sinogram for every block size. The results showed that the proposed method improved the image quality. This study showed that simulation studies are useful tools in the investigation of nuclear medicine researches. We produced a nonattenuated model using Monte Carlo simulation method and compared it with an attenuated model. The proposed reconstruction method improved image resolution and contrast. Regional and general similarities of images could be determined, respectively, from acquired UIQI of small and large block sizes. Resulted curves from both small and large block sizes showed a good similarity between reconstructed and ideal images.

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Section: Discussionmentioning

confidence: 99%

“…Although each of the proposed methods has been successful to somewhat, the attenuation problem is still not fully solved, and therefore, the use of quantitative methods is difficult in SPECT due to attenuation. [ 6 7 13 14 15 16 ]…”

Section: Introductionmentioning

confidence: 99%

Attenuation correction in single-photon emission computed tomography for NURBS-based cardiac-torso phantom using dual-energy acquisition

et al. 2020

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“…235) and DCCs was proposed in Ref. 236. In their work, the authors exploited the µ-λ crosstalk for segmentation and used a DCC-based algorithm to find each segment's optimal µ value.…”

Section: Spect-specific Studiesmentioning

confidence: 99%

Attenuation correction in emission tomography using the emission data—A review

Berker

2016

Medical Physics

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The problem of attenuation correction (AC) for quantitative positron emission tomography (PET) had been considered solved to a large extent after the commercial availability of devices combining PET with computed tomography (CT) in 2001; single photon emission computed tomography (SPECT) has seen a similar development. However, stimulated in particular by technical advances toward clinical systems combining PET and magnetic resonance imaging (MRI), research interest in alternative approaches for PET AC has grown substantially in the last years. In this comprehensive literature review, the authors first present theoretical results with relevance to simultaneous reconstruction of attenuation and activity. The authors then look back at the early history of this research area especially in PET; since this history is closely interwoven with that of similar approaches in SPECT, these will also be covered. We then review algorithmic advances in PET, including analytic and iterative algorithms. The analytic approaches are either based on the Helgason-Ludwig data consistency conditions of the Radon transform, or generalizations of John's partial differential equation; with respect to iterative methods, we discuss maximum likelihood reconstruction of attenuation and activity (MLAA), the maximum likelihood attenuation correction factors (MLACF) algorithm, and their offspring. The description of methods is followed by a structured account of applications for simultaneous reconstruction techniques: this discussion covers organ-specific applications, applications specific to PET/MRI, applications using supplemental transmission information, and motion-aware applications. After briefly summarizing SPECT applications, we consider recent developments using emission data other than unscattered photons. In summary, developments using time-of-flight (TOF) PET emission data for AC have shown promising advances and open a wide range of applications. These techniques may both remedy deficiencies of purely MRI-based AC approaches in PET/MRI and improve standalone PET imaging. C

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“…Designing such a dual-modality system also considerably complicates both the scanner design and the data acquisition and processing protocols. 15 Due to these reasons, the possibility to perform attenuation and scatter correction without the need for transmission CT data is important and can have significant and immediate clinical impact. 2 …”

Section: Introductionmentioning

confidence: 99%

“…These algorithms either try to perform iterative inversion of the forward mathematical model, 16–19 or exploit the consistency conditions that are based on the forward model. 15, 20–22 However, these methods are considerably slow, and mostly use only the data around the photopeak events neglecting the scattered photons. The techniques have met with only limited success.…”

Section: Introductionmentioning

confidence: 99%

Joint reconstruction of activity and attenuation map using LM SPECT emission data

Jha

Clarkson

Kupinski

et al. 2013

Medical Imaging 2013: Physics of Medical Imaging

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Attenuation and scatter correction in single photon emission computed tomography (SPECT) imaging often requires a computed tomography (CT) scan to compute the attenuation map of the patient. This results in increased radiation dose for the patient, and also has other disadvantages such as increased costs and hardware complexity. Attenuation in SPECT is a direct consequence of Compton scattering, and therefore, if the scattered photon data can give information about the attenuation map, then the CT scan may not be required. In this paper, we investigate the possibility of joint reconstruction of the activity and attenuation map using list-mode (LM) SPECT emission data, including the scattered-photon data. We propose a path-based formalism to process scattered-photon data. Following this, we derive analytic expressions to compute the Cramér-Rao bound (CRB) of the activity and attenuation map estimates, using which, we can explore the fundamental limit of information-retrieval capacity from LM SPECT emission data. We then suggest a maximum-likelihood (ML) scheme that uses the LM emission data to jointly reconstruct the activity and attenuation map. We also propose an expectation-maximization (EM) algorithm to compute the ML solution.

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Attenuation map estimation with SPECT emission data only

Cited by 14 publications

References 25 publications

Attenuation correction in single-photon emission computed tomography for NURBS-based cardiac-torso phantom using dual-energy acquisition

Attenuation correction in single-photon emission computed tomography for NURBS-based cardiac-torso phantom using dual-energy acquisition

Attenuation correction in emission tomography using the emission data—A review

Joint reconstruction of activity and attenuation map using LM SPECT emission data

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