Physical Performance of the new hybrid PET/CT Discovery-690

Bettinardi, Valentino; Presotto, Luca; Rapisarda, E.; Picchio, Maria; Gianolli, Luigi; Gilardi, M.C.

doi:10.1118/1.3635220

Cited by 346 publications

(298 citation statements)

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“…A combination of the PSF and TOF algorithm provided the best image quality among the reconstruction algorithms using either PSF or TOF (27). Both PSF and TOF greatly improved image quality: not only in the phantom study but also in the clinical study.…”

Section: Discussionmentioning

confidence: 88%

Improvement in PET/CT Image Quality with a Combination of Point-Spread Function and Time-of-Flight in Relation to Reconstruction Parameters

et al. 2012

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The aim of this study was to investigate the effects of the pointspread function (PSF) and time-of-flight (TOF) on improving 18 F-FDG PET/CT images in relation to reconstruction parameters and noise-equivalent counts (NEC). Methods: This study consisted of a phantom study and a retrospective analysis of 39 consecutive patients who underwent clinical 18 F-FDG PET/CT. The body phantom of the National Electrical Manufacturers Association and International Electrotechnical Commission with a 10-mm-diameter sphere was filled with an 18 F-FDG solution with a 4:1 radioactivity ratio compared with the background. The PET data were reconstructed with the baseline orderedsubsets expectation maximization (OSEM) algorithm, with the OSEM1PSF model, with the OSEM1TOF model, and with the OSEM1PSF1TOF model. We evaluated image quality by visual assessment, the signal-to-noise ratio of the 10-mm sphere (SNR 10 mm ), the contrast of the 10-mm sphere, and the coefficient of variance in the phantom study and then determined the optimal reconstruction parameters. We also examined the effects of PSF and TOF on the quality of clinical images using the signal-to-noise ratio in the liver (SNR liver ) in relation to the NEC in the liver (NEC liver ). Results: In the phantom study, the SNR 10 mm was the highest for the OSEM1PSF1TOF model, and the highest value was obtained at iteration 2 for algorithms with the TOF and at iteration 3 for those without the TOF. In terms of a postsmoothing filter full width at half maximum (FWHM), the high SNR 10 mm was obtained with no filtering or was smaller than 2 mm for algorithms with PSF and was 4-6 mm for those without PSF. The balance between the contrast recovery and noise is different for algorithms with either PSF or TOF. A combination of PSF and TOF improved SNR 10 mm , contrast, and coefficient of variance, especially with a small-FWHM gaussian filter. In the clinical study, the SNR liver of the low-NEC liver group in the OSEM1PSF1TOF model was compared with that of the high-NEC liver group in conventional OSEM. The PSF1TOF improved the SNR liver by about 24.9% 6 9.81%. Conclusion: A combination of PSF and TOF clearly improves image quality, whereas optimization of the reconstruction parameters is necessary to obtain the best performance for PSF or TOF. Furthermore, this combination has the potential to provide good image quality with either lower activity or shorter acquisition time, thus improving patient comfort and reducing the radiation burden. PET/ CT with 18 F-FDG is useful for the detection and staging of various malignant tumors, monitoring of their response to therapy, and prognostic stratification (1-6). High image quality is required for an accurate diagnosis, although the spatial resolution of PET is relatively low in comparison to other imaging modalities (7). Recently, the information provided by the point-spread function (PSF) and time-of-flight (TOF) has been expected to improve the spatial resolution and signal-to-noise ratio (SNR), respectively, of PET images (8-10).A PET sca...

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Section: Discussionmentioning

confidence: 88%

Improvement in PET/CT Image Quality with a Combination of Point-Spread Function and Time-of-Flight in Relation to Reconstruction Parameters

et al. 2012

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“…Therefore, precise preoperative nodal staging is critical for optimal treatment planning and the long-term survival of patients (19). However, despite rapid advances In studies using phantoms, TOF technique in PET/CT has been reported to show superior performance regarding small-lesion detection, signal-to-noise ratio (SNR), and contrast resolution (18,20,21). However, quantifying and transferring these improvements to the clinical setting is complex.…”

Section: Discussionmentioning

confidence: 99%

“…Although head and neck CT scanning and MR imaging are still considered the standard imaging tests for HNSCC, there has been more evidence suggesting that PET should routinely be added to improve staging of nodal or distant disease, detection of unknown primary lesions, and surveillance for recurrence (5). 18 F-FDG PET alone was reported to achieve a sensitivity of 87%-90% and a specificity of 80%-93% in nodal staging (6). The sensitivity, specificity, and accuracy of dual-modality PET/CT were reported to be 81.1%, 98.2%, and 95.0%, respectively (7).…”

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confidence: 99%

Effect of Time-of-Flight Technique on the Diagnostic Performance of 18F-FDG PET/CT for Assessment of Lymph Node Metastases in Head and Neck Squamous Cell Carcinoma

Klohr

Sadick

et al. 2014

Journal of Nuclear Medicine Technology

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Precise assessment of lymph node metastases is critical to the treatment outcome and overall survival of patients with head and neck squamous cell carcinoma (HNSCC). The purpose of this study was to investigate the effect of time-of-flight (TOF) technique on the diagnostic performance of 18 F-FDG PET/CT for assessment of lymph node metastases in HNSCC patients. Methods: In 39 patients with an initial diagnosis of HNSCC, preoperative staging 18 F-FDG PET/CT was performed to assess lymph node metastases before surgery and histologic verification. Potential lymph node metastases were evaluated and documented separately for the right and left neck in accordance with the head and neck lymph node level classification. Two experienced readers measured lesion volume and uptake for every PET-positive lymph node. Sensitivity, specificity, image quality, and the PET characterization of the lesion (benign or malignant) were compared between different reconstruction methods (TOF PET and standard high-definition PET) and matrices for both readers. Results: TOF PET significantly increased the maximal standardized uptake value (SUV max ) but had no significant effect on lesion volume. However, a higher SUV max did not result in a significant increase in small-lesion detection. Sensitivity and image quality were slightly improved with TOF PET but not significantly so. Matrix, on the other hand, had a significant effect on detected lesion numbers, sensitivity, and image quality. Conclusion: For preoperative assessment of lymph node metastases in HNSCC, 18 F-FDG PET/CT using TOF technique increases SUV max in lesions and improves image quality but has no significant impact on small-lesion detectability. Head and neck squamous cell carcinoma (HNSCC) is still a common cause of death. It is the fifth most common malignancy in the world, with approximately 650,000 new cases reported annually (1). The presence and extent of lymph node metastases is critical for prognosis evaluation and treatment planning. The number, distribution, and size of lymph nodes are equally important for nodal staging of head and neck cancer (2). Ultrasound and conventional cross-sectional imaging, which depend mainly on size criteria, have difficulty in differentiating between reactive lymph nodes and tumor-infiltrated nodes. Diffusionweighted MR imaging of the head and neck region has been shown to improve the outcome of lymph node staging (3). A new dedicated software application, syngo ZOOMit (Siemens Healthcare), has substantially improved image quality and reduced susceptibility artifacts in pancreatic diffusionweighted MR imaging (4) and has also shown practical potential in the head and neck region because it reduces distortion and better delineates cervical lymph nodes. Although head and neck CT scanning and MR imaging are still considered the standard imaging tests for HNSCC, there has been more evidence suggesting that PET should routinely be added to improve staging of nodal or distant disease, detection of unknown primary lesions, and surveillance...

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“…Most of the current approaches to tackle the problem of the reconstruction of isotope concentration distribution can be classified into two general categories, namely the analytical methods [11,12], which rely on the inversion of Radon transform, and the iterative approaches [13,14,15,16], which are mainly based on a statistical description of the physical problem. Because of the random nature of radioactive disintegration, the tomographic data are noisy and therefore it is logical to regard PET reconstruction as a statistical estimation problem.…”

Section: Introductionmentioning

confidence: 99%

RECONSTRUCTION OF MaxEnt IMAGES FROM PET CAMERA

Üstündağ¹

2017

RAD Conference Proceedings

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Abstract. We study here one of the imaging techniques, used in nuclear medicine, called a Positron Emission Tomographic (PET) imaging that provides information about many biological processes that are essential to the functioning of the organ that is being visualized. Our emphasis is given to applications of the maximum entropy image reconstruction method called "Cambridge MaxEnt Package" (CMEP) for recovering images of the human brain from data obtained by PET camera. Computer simulations demonstrate its usefulness.

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Physical Performance of the new hybrid PET/CT Discovery-690

Cited by 346 publications

References 50 publications

Improvement in PET/CT Image Quality with a Combination of Point-Spread Function and Time-of-Flight in Relation to Reconstruction Parameters

Improvement in PET/CT Image Quality with a Combination of Point-Spread Function and Time-of-Flight in Relation to Reconstruction Parameters

Effect of Time-of-Flight Technique on the Diagnostic Performance of 18F-FDG PET/CT for Assessment of Lymph Node Metastases in Head and Neck Squamous Cell Carcinoma

RECONSTRUCTION OF MaxEnt IMAGES FROM PET CAMERA

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