2 edition of Evaluation of factors affecting quantitation with a 3-D rotating partial ring PET scanner found in the catalog.
Evaluation of factors affecting quantitation with a 3-D rotating partial ring PET scanner
D. A. Bitzilekis
Written in English
Thesis (M.Sc.) - University of Surrey, 1996.
|Statement||D. A. Bitzilekis.|
|Contributions||University of Surrey. Department of Physics.|
Many of these factors can be addressed with close attention to detail and appropriate quality control. This article will review factors potentially affecting SUV measurements and provide recommendations on ways to minimize when using serial PET to assess early response to therapy. CONCLUSION. •Factors that affect quantitative accuracy •Quantitative imaging - what is required? 10/25/ R. Doot Why Quantify PET Images? Before Therapy After Therapy Patient 1 Patient 2 10/25/ R. Doot (Specht Br Ca Res Treat ) FDG PET uptake predicts outcome of bone-dominant breast cancer Time to progression Time to skeletal-related event.
Objectives: Rheumatoid Arthritis (RA) and Psoriatic Arthritis (PsA) commonly affect the small joints of the wrist and hand. We evaluated the performance of a new, high-resolution extremity PET. Abstract. The effect of multiple patient-related factors on the degree of cardiac 18 F-FDG uptake was assessed. Methods: Five hundred four consecutive patients undergoing routine 18 F-FDG PET/CT studies completed a clinical questionnaire. 18 F-FDG uptake was measured as the mean standardized uptake value within the heart delineated on the CT component of the study.
There are wide variations in PET and PET/CT scanners, each having its own characteristics, PET acquisition pos-sibilities (e.g., acquisitions in 2-dimensional [2D] and 3-dimensional [3D] modes), image reconstruction methods, and software for visualization and data analysis. The performance of a PET or PET/CT scanner is generally. For the PET/CT scanner used in the phantom studies (Biograph; Siemens Medical Solutions USA, Inc.), the spatial resolution increases by about 1 mm at 10 cm from the scanner isocenter. In our validation, the surrogate tumors and phantoms were typically located within 10 cm from the center of the field of view and, thus, permitted us to use a PSF.
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Abstract. Objective: The purpose of this paper is to introduce technologists to the basic principles of PET imaging and to the instrumentation used to acquire PET data.
PET imaging is currently being done on a variety of imaging system types, and the technologist will be introduced to these systems and learn about the basic physical image-degrading factors in PET.
Image-based partial volume correction. Iterative deconvolution methods Deconvolution is an image restoration process used to recover spatial resolution, restore edges and improve contrast. Two PVC methods based on iterative deconvolution were evaluated: Lucy-Richardson (LR)  and Van Cittert deconvolution (VC) .The LR method is initialized using a copy of the original PET Cited by: Errors in Numbers in PET/CT Technical factors Relative calibration between PET scanner and dose calibrator (10%) Time-varying scanner calibration (5%) Residual activity in syringe (5%) Incorrect synchronization of clocks (10%) Injection vs calibration time (10%) Quality of administration (50%) Physical factors Scan acquisition parameters (15%).
I. INTRODUCTION. The intrinsic physics limitations on reconstructed spatial resolution in a PET scanner are determined by the positron range which is a function of the positron energy , and the non-collinearity of the two annihilation photons [2, 3].For the most common radio-isotope used in routine clinical imaging, 18 F, the positron range leads to a.
Quantificatio n in 3 -D PET/CT Imaging J Instrument -related factors affecting quantification x spatial and energy resolution – partial volume effect – discriminate against scattered events x sensitivity: higher sensitivity => lower Poisson noise x data acquisition mode for PET (2 -D vs 3-D).
1. Introduction. Image formation on positron emission tomography (PET), as well as on any other linear imaging system, is completely described by its point spread function (PSF), generally dependent on spatial the assumption of spatial invariance, one PSF is defined for the complete field of view and the final image can be modelled as the Cited by: SSAD 3D reconstruction for multi-ring PET scanner Implementation In the implementation of the SSAD algorith, the 3D data are sorted by SSR into two sets of transaxial sinograms: one set including all LORs, '3D sinograms', and one set including only LORS within a limited axial acceptance angle, '2D sinograms'.Reconstruction of the 2D sinogams using.
Background. Positron emission tomography/computed tomography (PET/CT) using 18 F-fluorodeoxy-d-glucose (FDG) has become increasingly important for planning and evaluating the outcomes of treatment [1, 2] and this modality requires accurate quantitation of FDG uptake and distribution related to spatial r, a limitation associated with the PET Cited by: 5.
(a) The view of the Xtrim animal PET scanner with mm ring diameter (b). The simulated model of Xtrim using GATE MC Toolkit. Download: Download high-res image (KB) Download: Download full-size image; Fig. (a) Illustration of the preliminary scanner geometry with given ring diameter and transaxial FOV (b) crystal array in one block.
2-D vs. 3-D 2-D has reduced sensitivity, but improved resolution with reduction of scatter and random coincidence (usually scatter and random counts are only 15 - 20% of total counts) 3-D has has greater sensitivity, but is caused by increased scatter and random counts.
About 30 - 40% of all events recorded are scatter and random. Wiesmuller M, Quick HH, Navalpakkam B, Lell MM, Uder M, Ritt P, et al. Comparison of lesion detection and quantitation of tracer uptake between PET from a simultaneously acquiring whole-body PET/MR hybrid scanner and PET from PET/CT.
Eur J Nucl Med Mol Imaging. ; – doi: /sy. Dynamic PET Imaging Protocols. In dynamic PET scanning (Figure 1), the patient is positioned in the scanner and immobilized to restrict movement, after which catheter lines are placed in the lines provide not only vascular access for delivery of the tracer, but also provide for periodic blood sampling during the scan to assess radioactive delivery to the tissues.
Bailey DL, Townsend DW, Kinahan P, Grootoonk S, Jones T, "An investigation of factors affecting detector and geometric correction in normalisation of 3-D PET data", IEEE Trans. Nuc. Sci., vol. 43(6), pp.Oakes TR, Sossi V and Ruth TJ, "Normalization for 3D PET with a low-scatter planar source: Technique.
PET data acquisition (25 min) started 30 min after intravenous injection of approximately MBq of 18 F-[FDG] on the ECAT ART continuously rotating partial-ring positron tomograph (Siemens/CTI, Knoxville, TN) operated in fully 3D mode. This scanner is capable of acquiring both pre- and post-injection transmission scans.
A few factors affecting spatial resolution of a ring PET system are discussed. The approximate intrinsic spatial resolution at the center of a PET ring detector (in FWHM) is. One of the major physical factors affecting quantitation in DAT SPECT is partial volume effect due to the combination of limited spatial resolution of the gamma cameras available (~8 mm) and small size of the caudate nucleus and putamen (similar size to spatial resolution).
Learning Objectives 1. Illustrate factors that alter standard uptake values in FDG PET/CT to include patient, biodistribution and technical factors.
Discuss role of qualitative FDG uptake when SUV is unreliable in order to determine response to therapy. Describe quality control measures used. The PET/CT scanner was developed as a combination of a Siemens Somatom spiral CT and a partial-ring, rotating ECAT ART PET scanner.
All components are mounted on a common rotational support. Consider a patient who has a small tumor in the anterior portion of the brain as shown in Figure 1A (ellipse) undergoing imaging with a ring-style PET scanner.
The center of the PET gantry is also noted in the figure with a cross (X). A PET agent that localizes in the tumor has been administered to the patient. In time-of-flight (TOF) PET, the system timing resolution allows a more precise localization of the event along the LOR ().Ideally, if system timing resolution provides a spatial uncertainty Δx (Δx = c• Δt/2, where c is the speed of light in vacuum) along the LOR that is comparable or better than the detector spatial resolution, then image reconstruction can.
A full PET scanner is constructed as a cylindrical assembly of block detectors in a ring structure several blocks deep. The sensitive volume inside the detector cylinder that a patient can occupy is called the field-of-view (FOV), which in human scanners is typically 70 cm in diameter and 16 – 18 cm in axial length (Fig.
3).PET scanner axis Full q!max! m ax axial center plane axial end plane PET scanner sensitivity scales with the number of detectable coincidence events, which in turn scales as!
max. This results in lower sensitivity at the end of any PET scanner scanner axis! edge = 0 o! edg e source QA for PET Scanners: Evaluation of Performance Metrics.The limited spatial resolution and signal sampling in PET imaging leads to partial volume effect (PVE) [43, 84].
PVE causes an incorrect measurement (underestimation) of radiotracer concentration especially in regions whose size is smaller than 2–3 times the spatial resolution of the PET scanner.