3D PET List-Mode Iterative Reconstruction Using Time-Of-Flight Information

Groiselle, C.J.; Glick, Stephen J.

doi:10.1109/nssmic.2004.1462792

Cited by 26 publications

(18 citation statements)

References 11 publications

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“…2) Time-of-Flight Reconstruction: The ToF information is included in the ML-EM and MAP-EM algorithms by scaling the detection probability by a probability related to the time difference [29]. The time information is modelled by weighting the line of response by a Gaussian distribution with FWHM equal to the temporal resolution and mean equal to the expected position of the emission using .…”

Section: B Image Reconstruction: Total Variation 1) Map-em and Totalmentioning

confidence: 99%

PET Reconstruction From Truncated Projections Using Total-Variation Regularization for Hadron Therapy Monitoring

Cabello

Torres-Espallardó

Gillam

et al. 2013

IEEE Trans. Nucl. Sci.

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Hadron therapy exploits the properties of ion beams to treat tumors by maximizing the dose released to the target and sparing healthy tissue. With hadron beams, the dose distribution shows a relatively low entrance dose which rises sharply at the end of the range, providing the characteristic Bragg peak that drops quickly thereafter. It is of critical importance in order not to damage surrounding healthy tissues and/or avoid targeting underdosage to know where the delivered dose profile ends-the location of the Bragg peak. During hadron therapy, short-lived -emitters are produced along the beam path, their distribution being correlated with the delivered dose. Following positron annihilation, two photons are emitted, which can be detected using a positron emission tomography (PET) scanner. The low yield of emitters, their short half-life, and the wash out from the target region make the use of PET, even only a few minutes after hadron irradiation, a challenging application. In-beam PET represents a potential candidate to estimate the distribution of -emitters during or immediately after irradiation, at the cost of truncation effects and degraded image quality due to the partial rings required of the PET scanner. Time-of-flight (ToF) information can potentially be used to compensate for truncation effects and to enhance image contrast. However, the highly demanding timing performance required in ToF-PET makes this option costly. Alternatively, the use of maximum-a-posteriori-expectation-maximization (MAP-EM), including total variation (TV) in the cost function, produces images with low noise, while preserving spatial resolution. In this paper, we compare data reconstructed with maximum-likelihood-expectation-maximization (ML-EM) and MAP-EM using TV as prior, and the impact of including ToF information, from data acquired with a complete and a partial-ring PET scanner, of simulated hadron beams interacting Manuscript with a polymethyl methacrylate (PMMA) target. The results show that MAP-EM, in the absence of ToF information, produces lower noise images and more similar data compared to the simulated distributions than ML-EM with ToF information in the order of 200-600 ps. The investigation is extended to the combination of MAP-EM and ToF information to study the limit of performance using both approaches.Index Terms-Hadron therapy, in-beam PET, maximuma-posteriori-expectation-maximization (MAP-EM) reconstruction, time-of-flight positron emission tomography (PET), total variation.

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Section: B Image Reconstruction: Total Variation 1) Map-em and Totalmentioning

confidence: 99%

PET Reconstruction From Truncated Projections Using Total-Variation Regularization for Hadron Therapy Monitoring

Cabello

Torres-Espallardó

Gillam

et al. 2013

IEEE Trans. Nucl. Sci.

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“…Another application of the result presented here would be to use the inverse rebinning equation (29) to design a fully 3D TOF PET projector for iterative reconstruction as an extension of our recent fast maximum a posteriori (MAP) method (Cho et al 2007) as an alternative to other iterative TOF reconstruction methods for binned (Matej et al 2006), or list mode (Snyder and Politte 1983, Groiselle and Glick 2004, Surti et al 2007) data. Comparison of (top) noisy 2D direct sinogram with (bottom) noise reduction resulting from rebinning of oblique data into direct planes for (a) 500 ps, and (b) 250 ps resolution.…”

Section: Discussionmentioning

confidence: 99%

Analytical properties of time-of-flight PET data

Cho

Ahn

et al. 2008

Phys. Med. Biol.

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We investigate the analytical properties of time-of-flight (TOF) positron emission tomography (PET) sinograms, where the data are modeled as line integrals weighted by a spatially invariant TOF kernel. First, we investigate the Fourier transform properties of 2D TOF data and extend the "bow-tie" property of the 2D Radon transform to the time of flight case. Second, we describe a new exact Fourier rebinning method, TOF-FOREX, based on the Fourier transform in the time-offlight variable. We then combine TOF-FOREX rebinning with a direct extension of the projection slice theorem to TOF data, to perform fast 3D TOF PET image reconstruction. Finally, we illustrate these properties using simulated data.

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“…To mitigate the latter, Time-of-Flight (TOF) information can be integrated into the reconstruction algorithm (Shakirin 2009, Surti et al 2011. For image reconstruction, the Maximum Likelihood Estimation Maximization (MLEM) is a commonly used method for PET and provides the possibility to include TOF information (Groiselle and Glick 2004). The improvement in image quality achieved by TOF-MLEM reconstruction compared with standard MLEM for PET strongly depends on the time resolution of the scanner.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of resistive-plate-chamber-based TOF-PET applied to in-beam particle therapy monitoring

Torres-Espallardó¹,

Diblen²,

Rohling³

et al. 2015

Phys. Med. Biol.

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Particle therapy is a highly conformal radiotherapy technique which reduces the dose deposited to the surrounding normal tissues. In order to fully exploit its advantages, treatment monitoring is necessary to minimize uncertainties related to the dose delivery. Up to now, the only clinically feasible technique for the monitoring of therapeutic irradiation with particle beams is Positron Emission Tomography (PET). In this work we have compared a Resistive Plate Chamber (RPC)-based PET scanner with a scintillation-crystal-based PET scanner for this application. In general, the main advantages of the RPC-PET system are its excellent timing resolution, low cost, and the possibility of building large area systems. We simulated a partial-ring scanner based on an RPC prototype under construction within the Fondazione per Adroterapia Oncologica (TERA). For comparison with the crystal-based PET scanner we have chosen the geometry of a commercially available PET scanner, the Philips Gemini TF. The coincidence time resolution used in the simulations takes into account the current achievable values as well as expected improvements of both technologies. Several scenarios (including patient data) have been simulated to evaluate the performance of different scanners. Initial results have shown that the low sensitivity of the RPC hampers its application to hadron- Note Institute of Physics and Engineering in Medicine6 These authors contributed equally to the work. beam monitoring, which has an intrinsically low positron yield compared to diagnostic PET. In addition, for in-beam PET there is a further data loss due to the partial ring configuration. In order to improve the performance of the RPC-based scanner, an improved version of the RPC detector (modifying the thickness of the gas and glass layers), providing a larger sensitivity, has been simulated and compared with an axially extended version of the crystal-based device. The improved version of the RPC shows better performance than the prototype, but the extended version of the crystal-based PET outperforms all other options.

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3D PET List-Mode Iterative Reconstruction Using Time-Of-Flight Information

Cited by 26 publications

References 11 publications

PET Reconstruction From Truncated Projections Using Total-Variation Regularization for Hadron Therapy Monitoring

PET Reconstruction From Truncated Projections Using Total-Variation Regularization for Hadron Therapy Monitoring

Analytical properties of time-of-flight PET data

Evaluation of resistive-plate-chamber-based TOF-PET applied to in-beam particle therapy monitoring

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