Simultaneous estimation of SPECT activity and attenuation distributions from measured phantom data using a differential attenuation method

Vija, Hans; Kaplan, M.S.; Haynor, David R.

doi:10.1109/nssmic.1999.845805

Cited by 6 publications

(4 citation statements)

References 8 publications

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“…The technique does however have limitations when activity is focal. A number of researchers have previously attempted to derive an attenuation map directly from primary emission data, either using the differential attenuation for multi-energy emission (Vija et al 1999) or using consistency conditions for single-energy photon emission to extract an estimate of the attenuation (Bronnikov 2000, Nuyts et al 1999, Crepaldi and de Pierro 2007. The attempts to do this have met with limited success and have not been widely used.…”

Section: Using Scatter To Determine Attenuation Mapsmentioning

confidence: 99%

Review and current status of SPECT scatter correction

Hutton¹,

2011

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Detection of scattered gamma quanta degrades image contrast and quantitative accuracy of single-photon emission computed tomography (SPECT) imaging. This paper reviews methods to characterize and model scatter in SPECT and correct for its image degrading effects, both for clinical and small animal SPECT. Traditionally scatter correction methods were limited in accuracy, noise properties and/or generality and were not very widely applied. For small animal SPECT, these approximate methods of correction are often sufficient since the fraction of detected scattered photons is small. This contrasts with patient imaging where better accuracy can lead to significant improvement of image quality. As a result, over the last two decades, several new and improved scatter correction methods have been developed, although often at the cost of increased complexity and computation time. In concert with (i) the increasing number of energy windows on modern SPECT systems and (ii) excellent attenuation maps provided in SPECT/CT, some of these methods give new opportunities to remove degrading effects of scatter in both standard and complex situations and therefore are a gateway to highly quantitative single- and multi-tracer molecular imaging with improved noise properties. Widespread implementation of such scatter correction methods, however, still requires significant effort.

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Section: Using Scatter To Determine Attenuation Mapsmentioning

confidence: 99%

Review and current status of SPECT scatter correction

Hutton¹,

2011

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“…231 This study of scatter-free numerical studies was followed by an anthropomorphic phantom study including the effect of scattering. 232 A rather empirical approach of finding ACF for SPECT has been described in Ref. 233, using Fourier decomposition of the sinogram of ACF and optimization driven by DCCs.…”

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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“…Over the years, numerous correction methods have been proposed to mitigate these issues. Energy window-based correction methods like dual/triple/multiple energy window correction use several energy windows to estimate the scatter imaging and are widely applied [5][8] [9][10] [11] [12]. There are also correction methods based on spectral analysis, including spectra fitting to split the primary photopeak and gain high accuracy [13][14] [15].…”

Section: Introductionmentioning

confidence: 99%

Exploration of Coincidence Detection of Cascade Photons to Enhance Preclinical Multi-Radionuclide SPECT Imaging

Jin,

Meng

2024

IEEE Trans. Med. Imaging

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We proposed a technique of coincidence detection of cascade photons (CDCP) to enhance preclinical SPECT imaging of therapeutic radionuclides emitting cascade photons, such as Lu-177, Ac-225, Ra-223, and In-111. We have carried out experimental studies to evaluate the proposed CDCP-SPECT imaging of lowactivity radionuclides using a prototype coincidence detection system constructed with large-volume cadmium zinc telluride (CZT) imaging spectrometers and a pinhole collimator. With In-111 in experimental studies, the CDCP technique allows us to improve the signal-to-contamination in the projection (Projection-SCR) by ~53 times and reduce ~98% of the normalized contamination. Compared to traditional scatter correction, which achieves a Projection-SCR of 1.00, our CDCP method boosts it to 15.91, showing enhanced efficacy in reducing down-scattered contamination, especially at lower activities. The reconstructed images of a line source demonstrated the dramatic enhancement of the image quality with CDCP-SPECT compared to conventional and triple-energywindow-corrected SPECT data acquisition. We also introduced artificial energy blurring and Monte Carlo simulation to quantify the impact of detector performance, especially its energy resolution and timing resolution, on the enhancement through the CDCP technique. We have further demonstrated the benefits of the CDCP technique with simulation studies, which show the potential of improving the signal-to-contamination ratio by 300 times with Ac-225, which emits cascade photons with a decay constant of ~0.1 ns. These results have demonstrated the potential of CDCP-enhanced SPECT for imaging a superlow level of therapeutic radionuclides in small animals.

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Simultaneous estimation of SPECT activity and attenuation distributions from measured phantom data using a differential attenuation method

Cited by 6 publications

References 8 publications

Review and current status of SPECT scatter correction

Review and current status of SPECT scatter correction

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

Exploration of Coincidence Detection of Cascade Photons to Enhance Preclinical Multi-Radionuclide SPECT Imaging

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