Annihilation photon acollinearity in PET: volunteer and phantom FDG studies

Shibuya, Kengo; Yoshida, Eiji; Nishikido, Fumihiko; Suzuki, Toshikazu; Tsuda, Tomoaki; Inadama, Naoko; Yamaya, Taiga; Murayama, Hideo

doi:10.1088/0031-9155/52/17/010

Cited by 34 publications

(25 citation statements)

References 22 publications

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“…A is well described by a Gaussian distribution with FWHM = 2.35 σ = 0.0024 · D (Shibuya et al 2007), where D is the distance between the two detectors. Detailed measurements of the acolinearity in Shibuya et al (2007) yielded a blurring of 0.0024 · D rather than the more commonly used 0.0022 · D from Derenzo et al (1993).…”

Section: Testing the Designmentioning

confidence: 99%

Performance characterization of a new high resolution PET scintillation detector

et al. 2010

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Performance of a new high resolution PET detection concept is presented. In this new concept, annihilation radiation enters the scintillator detectors edge-on. Each detector module comprises two 8 × 8 LYSO scintillator arrays of 0.91 × 0.91 × 1 mm3 crystals coupled to two position-sensitive avalanche photodiodes (PSAPDs) mounted on a flex circuit. Appropriate crystal segmentation allows the recording of all three spatial coordinates of the interaction(s) simultaneously with submillimeter resolution. We report an average energy resolution of 14.6 ± 1.7% for 511 keV photons at FWHM. Coincident time resolution was determined to be 2.98 ± 0.13 ns FWHM on average. The coincidence point spread function (PSF) has an average FWHM of 0.837 ± 0.049 mm (using a 500 μm spherical source) and is uniform across the arrays. Both PSF and coincident time resolution degrade when Compton interactions are included in the data. Different blurring factors were evaluated theoretically, resulting in a calculated PSF of 0.793 mm, in good agreement with the measured value.

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Section: Testing the Designmentioning

confidence: 99%

Performance characterization of a new high resolution PET scintillation detector

et al. 2010

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“…However since the positronium has some non-zero kinetic energy when it decays, the angle of emission for the photons is not perfectly 180°. Rather 180° is the mean angle with an acollinearity of 0.2° FWHM (Colombino, Fiscella, & Trossi, 1965;Shibuya et al, 2007). This error, the FOV where the LOR density varies the most.…”

Section: Spatial Resolution Of a Pet Scannermentioning

confidence: 96%

An algorithm for automatic crystal identification in pixelated scintillation detectors using thin plate splines and Gaussian mixture models

2016

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Positron emission tomography (PET) is a non-invasive imaging technique which utilizes positronemitting radiopharmaceuticals (PERs) to characterize biological processes in tissues of interest. A PET scanner is usually composed of multiple scintillation crystal detectors placed in a ring so as to capture coincident photons from a position annihilation. These detectors require a crystal lookup table (CLUT) to map the detector response to the crystal of interaction. These CLUTs must be accurate, lest events get mapped to the wrong crystal of interaction degrading the final image quality. This work describes an automated algorithm, for CLUT generation, focused around Gaussian Mixture Models (GMM) with Thin Plate Splines (TPS). The algorithm was tested with flood image data collected from 16 detectors. The method maintained at least 99.8% accuracy across all tests. This method is considerably faster than manual techniques and can be adapted to different detector configurations.iii Acknowledgements

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“…Thus, for a given emission angle other than 180 degrees, the acollinearity effect is expected to trigger a resolution loss or blurring proportional to the average distance the photons travel before hitting a detector, the latter being directly proportional to the scanner detector ring diameter. 39 Inter-crystal penetration involves the undetected crossing of a photon through the first crystal detector intercepting its path, before its final detection in another proximal detector. This effect mainly occurs for photons scattered within the first crystal or photons hitting the front surface of the first crystal at a relatively large angle of incidence, such that its trajectory path length within that crystal is not sufficiently long for its complete stop before penetrating to the next crystal intercepting the photon path.…”

Section: Overview Of Physical and Imaging Factors Impacting Quantitatmentioning

confidence: 99%

Towards enhanced PET quantification in clinical oncology

Zaidi

Karakatsanis

2017

The British Journal of Radiology

101

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Positron emission tomography (PET) has, since its inception, established itself as the imaging modality of choice for the in vivo quantitative assessment of molecular targets in a wide range of biochemical processes underlying tumour physiology. PET image quantification enables to ascertain a direct link between the time-varying activity concentration in organs/tissues and the fundamental parameters portraying the biological processes at the cellular level being assessed. However, the quantitative potential of PET may be affected by a number of factors related to physical effects, hardware and software system specifications, tracer kinetics, motion, scan protocol design and limitations in current image-derived PET metrics. Given the relatively large number of PET metrics reported in the literature, the selection of the best metric for fulfilling a specific task in a particular application is still a matter of debate. Quantitative PET has advanced elegantly during the last two decades and is now reaching the maturity required for clinical exploitation, particularly in oncology where it has the capability to open many avenues for clinical diagnosis, assessment of response to treatment and therapy planning. Therefore, the preservation and further enhancement of the quantitative features of PET imaging is crucial to ensure that the full clinical value of PET imaging modality is utilized in clinical oncology. Recent advancements in PET technology and methodology have paved the way for faster PET acquisitions of enhanced sensitivity to support the clinical translation of highly quantitative four-dimensional (4D) parametric imaging methods in clinical oncology. In this report, we provide an overview of recent advances and future trends in quantitative PET imaging in the context of clinical oncology. The pros/cons of the various image-derived PET metrics will be discussed and the promise of novel methodologies will be highlighted. iNtroductioN Image-guided diagnosis and treatment response monitoring in clinical oncology has benefited significantly over the last decades from the advent of quantitative molecular imaging techniques. Among those, positron emission tomography (PET) gradually emerged as the standard-of-care molecular imaging modality in clinical oncology owing to its relatively high sensitivity and specificity for a wide spectrum of oncological malignancies across the whole human body.1 PET imaging relies on the positron/electron annihilation process to quantify the in vivo three-dimensional (3D) spatial distribution of a positron-emitting radiotracer associated with a specific molecular process. The resulting 3D PET

show abstract

Annihilation photon acollinearity in PET: volunteer and phantom FDG studies

Cited by 34 publications

References 22 publications

Performance characterization of a new high resolution PET scintillation detector

Performance characterization of a new high resolution PET scintillation detector

An algorithm for automatic crystal identification in pixelated scintillation detectors using thin plate splines and Gaussian mixture models

Towards enhanced PET quantification in clinical oncology

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