An OpenPET scanner with bridged detectors to compensate for incomplete data

Tashima, Hideaki; Yamaya, Taiga; Kinahan, Paul E.

doi:10.1088/0031-9155/59/20/6175

Cited by 6 publications

(4 citation statements)

References 33 publications

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“…To enlarge the axial FOV without increasing cost, the concept of open-gap PET was proposed and a prototype scanner has been built for pre-clinical research (Yoshida et al 2010, Yamaya et al 2011). However, this design provides no improvement in sensitivity and the reconstructed images may have artifacts due to incomplete sampling issues (Tashima et al 2014). …”

Section: Introductionmentioning

confidence: 99%

Quantitative image reconstruction for total-body PET imaging using the 2-meter long EXPLORER scanner

et al. 2017

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The EXPLORER project aims to build a 2-meter long total-body PET scanner, which will provide extremely high sensitivity for imaging the entire human body. It will possess a range of capabilities currently unavailable to state-of-the-art clinical PET scanners with a limited axial field-of-view. The huge number of lines-of-response (LORs) of the EXPLORER poses a challenge to the data handling and image reconstruction. The objective of this study is to develop a quantitative image reconstruction method for the EXPLORER and compare its performance with current whole-body scanners. Fully 3D image reconstruction was performed using time-of-flight list-mode data with parallel computation. To recover the resolution loss caused by the parallax error between crystal pairs at a large axial ring difference or transaxial radial offset, we applied an image domain resolution model estimated from point source data. To evaluate the image quality, we conducted computer simulations using the SimSET Monte-Carlo toolkit and XCAT 2.0 anthropomorphic phantom to mimic a 20-minute whole-body PET scan with an injection of 25 MBq 18F-FDG. We compare the performance of the EXPLORER with a current clinical scanner that has an axial FOV of 22 cm. The comparison results demonstrated superior image quality from the EXPLORER with a 6.9-fold reduction in noise standard deviation comparing with multi-bed imaging using the clinical scanner.

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Section: Introductionmentioning

confidence: 99%

Quantitative image reconstruction for total-body PET imaging using the 2-meter long EXPLORER scanner

et al. 2017

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“…The spatial resolution was characterized by the full width at half maximum (FWHM) [27] of the point sources. The NMSE [28] was defined as follows:

\begin{matrix} T1 \\ NMSE = \frac{\sum_{m = normal0}^{M - normal1} \sum_{n = normal0}^{N - normal1} {(f (m, n) - t (m, n))}^{2}}{\sum_{m = normal0}^{M - normal1} \sum_{n = normal0}^{N - normal1} t (m, n)}, \end{matrix}

where f ( m , n ) and t ( m , n ) were the pixel values of the reconstructed image and true image, respectively. M and N were the number of rows and columns in the images.…”

Section: Methodsmentioning

confidence: 99%

Influence of Rotation Increments on Imaging Performance for a Rotatory Dual-Head PET System

Meng

Cao

et al. 2017

BioMed Research International

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For a rotatory dual-head positron emission tomography (PET) system, how to determine the rotation increments is an open problem. In this study, we simulated the characteristics of a rotatory dual-head PET system. The influences of different rotation increments were compared and analyzed. Based on this simulation, the imaging performance of a prototype system was verified. A reconstruction flowchart was proposed based on a precalculated system response matrix (SRM). The SRM made the relationships between the voxels and lines of response (LORs) fixed; therefore, we added the interpolation method into the flowchart. Five metrics, including spatial resolution, normalized mean squared error (NMSE), peak signal-to-noise ratio (PSNR), contrast-to-noise (CNR), and structure similarity (SSIM), were applied to assess the reconstructed image quality. The results indicated that the 60° rotation increments with the bilinear interpolation had advantages in resolution, PSNR, NMSE, and SSIM. In terms of CNR, the 90° rotation increments were better than other increments. In addition, the reconstructed images of 90° rotation increments were also flatter than that of 60° increments. Therefore, both the 60° and 90° rotation increments could be used in the real experiments, and which one to choose may depend on the application requirement.

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“…We are developing the world's first, open-geometry PET scanner, OpenPET, which can provide a physically opened field of view (FOV) of isotropic 3D spatial resolution (Yamaya et al 2008, 2009a, 2009b, 2009c, 2011, Yoshida et al 2010, 2012, Tashima et al 2012a, 2014a, 2014b. The main application of the OpenPET scanner is in-beam PET imaging for particle therapy (Iseki et al 2003, Enghardt et al 2004, Inaniwa et al 2006, Nishio et al 2006, Crespo et al 2006, 2007, Fiedler et al 2010 (figure 1).…”

Section: Introductionmentioning

confidence: 99%

Development of a small single-ring OpenPET prototype with a novel transformable architecture

Tashima¹,

Yoshida²,

Inadama³

et al. 2016

Phys. Med. Biol.

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The single-ring OpenPET (SROP), for which the detector arrangement has a cylinder shape cut by two parallel planes at a slant angle to form an open space, is our original proposal for in-beam PET. In this study, we developed a small prototype of an axial-shift type SROP (AS-SROP) with a novel transformable architecture for a proof-of-concept. In the AS-SROP, detectors originally forming a cylindrical PET are axially shifted little by little. We designed the small AS-SROP prototype for 4-layer depth-of-interaction detectors arranged in a ring diameter of 250 mm. The prototype had two modes: open and closed. The open mode formed the SROP with the open space of 139 mm and the closed mode formed a conventional cylindrical PET. The detectors were simultaneously moved by a rotation handle allowing them to be transformed between the two modes. We evaluated the basic performance of the developed prototype and carried out in-beam imaging tests in the HIMAC using (11)C radioactive beam irradiation. As a result, we found the open mode enabled in-beam PET imaging at a slight cost of imaging performance; the spatial resolution and sensitivity were 2.6 mm and 5.1% for the open mode and 2.1 mm and 7.3% for the closed mode. We concluded that the AS-SROP can minimize the decrease of resolution and sensitivity, for example, by transforming into the closed mode immediately after the irradiation while maintaining the open space only for the in-beam PET measurement.

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An OpenPET scanner with bridged detectors to compensate for incomplete data

Cited by 6 publications

References 33 publications

Quantitative image reconstruction for total-body PET imaging using the 2-meter long EXPLORER scanner

Quantitative image reconstruction for total-body PET imaging using the 2-meter long EXPLORER scanner

Influence of Rotation Increments on Imaging Performance for a Rotatory Dual-Head PET System

Development of a small single-ring OpenPET prototype with a novel transformable architecture

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