scholarly journals ORIS: the Oak Ridge Imaging System program listings. [Nuclear medicine imaging with rectilinear scanner and gamma camera]

1978 ◽  
Author(s):  
P. R. Bell ◽  
J. M. Dougherty
Keyword(s):  
Nuclear Medicine ◽  
Gamma Camera ◽  
Imaging System ◽  
Nuclear Medicine Imaging ◽  
Oak Ridge ◽  
System Program

scholarly journals Correction for the Partial Volume Effects (PVE) in Nuclear Medicine Imaging: A Post-Reconstruction Analytic Method

2021 ◽  
Vol 11 (14) ◽  
pp. 6460
Author(s):  
Fabio Di Martino ◽  
Patrizio Barca ◽  
Eleonora Bortoli ◽  
Alessia Giuliano ◽  
Duccio Volterrani
Keyword(s):  
Nuclear Medicine ◽  
Imaging System ◽  
Tomographic Reconstruction ◽  
Mathematical Expression ◽  
Reconstruction Algorithm ◽  
Volume Effect ◽  
Nuclear Medicine Imaging ◽  
Theoretical Derivation ◽  
Reconstruction Process ◽  
Partial Volume

Quantitative analyses in nuclear medicine are increasingly used, both for diagnostic and therapeutic purposes. The Partial Volume Effect (PVE) is the most important factor of loss of quantification in Nuclear Medicine, especially for evaluation in Region of Interest (ROI) smaller than the Full Width at Half Maximum (FWHM) of the PSF. The aim of this work is to present a new approach for the correction of PVE, using a post-reconstruction process starting from a mathematical expression, which only requires the knowledge of the FWHM of the final PSF of the imaging system used. After the presentation of the theoretical derivation, the experimental evaluation of this method is performed using a PET/CT hybrid system and acquiring the IEC NEMA phantom with six spherical “hot” ROIs (with diameters of 10, 13, 17, 22, 28, and 37 mm) and a homogeneous “colder” background. In order to evaluate the recovery of quantitative data, the effect of statistical noise (different acquisition times), tomographic reconstruction algorithm with and without time-of-flight (TOF) and different signal-to-background activity concentration ratio (3:1 and 10:1) was studied. The application of the corrective method allows recovering the loss of quantification due to PVE for all sizes of spheres acquired, with a final accuracy less than 17%, for lesion dimensions larger than two FWHM and for acquisition times equal to or greater than two minutes.

Modular 64×64 CdZnTe Arrays With Multiplexer Readout for High-Resolution Nuclear Medicine Imaging

1997 ◽  
Vol 487 ◽  
Author(s):  
J. M. Woolfenden ◽  
H. B. Barber ◽  
H. H. Barrett ◽  
E. L. Dereniak ◽  
J. D. Eskin ◽  
...  
Keyword(s):  
Nuclear Medicine ◽  
High Resolution ◽  
Spatial Resolution ◽  
Personal Computer ◽  
Imaging System ◽  
Radiation Detectors ◽  
Readout Circuit ◽  
Nuclear Medicine Imaging ◽  
Pixel Pitch

AbstractWe are developing modular arrays of CdZnTe radiation detectors for high-resolution nuclear medicine imaging. Each detector is delineated into a 64×64 array of pixels; the pixel pitch is 380 jim. Each pixel is connected to a corresponding pad on a multiplexer readout circuit. The imaging system is controlled by a personal computer. We obtained images of standard nuclear medicine phantoms in which the spatial resolution of approximately 1.5 mm was limited by the collimator that was used. Significant improvements in spatial resolution should be possible with different collimator designs. These results are promising for high-resolution nuclear medicine imaging.

Nuclear Medicine Imaging and Therapy in Rheumatology

2013 ◽  
pp. 531-539
Author(s):  
Adil Al-Nahhas ◽  
Imene Zerizer
Keyword(s):  
Nuclear Medicine ◽  
Gamma Camera ◽  
Structural Changes ◽  
Response To Treatment ◽  
Nuclear Medicine Imaging ◽  
Inflammatory Conditions ◽  
Positron Emission ◽  
Pet Radiopharmaceutical ◽  
Monitoring Response

The application of nuclear medicine techniques in the diagnosis and management of rheumatological conditions relies on its ability to detect physiological and pathological changes in vivo, usually at an earlier stage compared to structural changes visualized on conventional imaging. These techniques are based on the in-vivo administration of a gamma-emitting radionuclide whose distribution can be monitored externally using a gamma camera. To guide a radionuclide to the area of interest, it is usually bound to a chemical label to form a ’radiopharmaceutical’. There are hundreds of radiopharmaceuticals in clinical use with different ’homing’ mechanisms, such as 99 mTc HDP for bone scan and 99 mTc MAA for lung scan. Comparing pre- and posttherapy scans can aid in monitoring response to treatment. More recently, positron emission tomography combined with simultaneous computed tomography (PET/CT) has been introduced into clinical practice. This technique provides superb spatial resolution and anatomical localization compared to gamma-camera imaging. The most widely used PET radiopharmaceutical, flurodeoxyglucose (18F-FDG), is a fluorinated glucose analogue, which can detect hypermetabolism and has therefore been used in imaging and monitoring response to treatment of a variety of cancers as well as inflammatory conditions such as vasculitis, myopathy, and arthritides. Other PET radiopharmaceuticals targeting inflammation and activated macrophages are becoming available and could open new frontiers in PET imaging in rheumatology. Nuclear medicine procedures can also be used therapeutically. Beta-emitting radiopharmaceuticals, such as yttrium-90, invoke localized tissue damage at the site of injection and can be used in the treatment of synovitis.

Modular 64×64 CdZnTe Arrays With Multiplexer Readout for High-Resolution Nuclear Medicine Imaging

1997 ◽  
Vol 484 ◽  
Author(s):  
J. M. Woolfenden ◽  
H. B. Barber ◽  
H. H. Barrett ◽  
E. L. Dereniak ◽  
J. D. Eskin ◽  
...  
Keyword(s):  
Nuclear Medicine ◽  
High Resolution ◽  
Spatial Resolution ◽  
Personal Computer ◽  
Imaging System ◽  
Radiation Detectors ◽  
Readout Circuit ◽  
Nuclear Medicine Imaging ◽  
Pixel Pitch

AbstractWe are developing modular arrays of CdZnTe radiation detectors for high-resolution nuclear medicine imaging. Each detector is delineated into a 64×64 array of pixels; the pixel pitch is 380 ptm. Each pixel is connected to a corresponding pad on a multiplexer readout circuit. The imaging system is controlled by a personal computer. We obtained images of standard nuclear medicine phantoms in which the spatial resolution of approximately 1.5 mm was limited by the collimator that was used. Significant improvements in spatial resolution should be possible with different collimator designs. These results are promising for high-resolution nuclear medicine imaging.

Thyroid imaging: nuclear medicine techniques

2011 ◽  
pp. 345-354
Author(s):  
I. Ross McDougall ◽  
Andrei Iagaru
Keyword(s):  
Nuclear Medicine ◽  
Thyroid Cancer ◽  
Gamma Camera ◽  
Radioactive Tracer ◽  
Quantitative Information ◽  
Whole Body ◽  
Congenital Defects ◽  
Nuclear Medicine Imaging ◽  
Thyroid Imaging ◽  
Uptake Measurement

Thyroid imaging with radio-isotopes of iodine provides functional and quantitative information. Images, scans, or scintiscans are the terms used for the pictures that are obtained. In general, a radionuclide or radiopharmaceutical is administered orally or intravenously and images of the distribution of the radioactive tracer are obtained after specific times using a gamma camera. Some clinicians employ a rectilinear scanner rather than a gamma camera to produce the images, but this should not be considered state of the art. Scintiscans do not have the resolution of ultrasonography, CT, or MRI, but they provide reasonable anatomical information as well as functional information. A numerical uptake measurement of how much of the tracer has been trapped can be obtained at the same time as the scintiscan to provide complementary quantitative information. Imaging with radio-iodine is of great value in the diagnosis and management of patients with thyrotoxicosis and differentiated thyroid cancer. It is of less value in thyroid nodules, hypothyroidism, simple goitre, and undifferentiated thyroid cancer. The chapter starts with a discussion of the radioactive tracers and the methods for scanning. Then the appearance of a normal scan followed by findings in patients with thyrotoxicosis, simple goitre, nodular goitre, and congenital defects are described. In these situations the scintiscan evaluates the region of the thyroid. Finally, the role of nuclear medicine imaging in patients with cancer of the thyroid is presented separately since the imaging is different in that it usually evaluates the whole body.

Patients with fever of unknown origin (FUO): diagnosis by nuclear medicine imaging

2001 ◽  
Vol 40 (03) ◽  
pp. 59-70 ◽  
Author(s):  
W. Becker ◽  
J. Meiler
Keyword(s):  
Nuclear Medicine ◽  
Fever Of Unknown Origin ◽  
Tumor Imaging ◽  
White Blood Cells ◽  
Unknown Origin ◽  
Final Diagnosis ◽  
Recurrent Fever ◽  
Nuclear Medicine Imaging

SummaryFever of unknown origin (FUO) in immunocompetent and non neutropenic patients is defined as recurrent fever of 38,3° C or greater, lasting 2-3 weeks or longer, and undiagnosed after 1 week of appropriate evaluation. The underlying diseases of FUO are numerous and infection accounts for only 20-40% of them. The majority of FUO-patients have autoimmunity and collagen vascular disease and neoplasm, which are responsible for about 50-60% of all cases. In this respect FOU in its classical definition is clearly separated from postoperative and neutropenic fever where inflammation and infection are more common. Although methods that use in-vitro or in-vivo labeled white blood cells (WBCs) have a high diagnostic accuracy in the detection and exclusion of granulocytic pathology, they are only of limited value in FUO-patients in establishing the final diagnosis due to the low prevalence of purulent processes in this collective. WBCs are more suited in evaluation of the focus in occult sepsis. Ga-67 citrate is the only commercially available gamma emitter which images acute, chronic, granulomatous and autoimmune inflammation and also various malignant diseases. Therefore Ga-67 citrate is currently considered to be the tracer of choice in the diagnostic work-up of FUO. The number of Ga-67-scans contributing to the final diagnosis was found to be higher outside Germany than it has been reported for labeled WBCs. F-l 8-2’-deoxy-2-fluoro-D-glucose (FDG) has been used extensively for tumor imaging with PET. Inflammatory processes accumulate the tracer by similar mechanisms. First results of FDG imaging demonstrated, that FDG may be superior to other nuclear medicine imaging modalities which may be explained by the preferable tracer kinetics of the small F-l 8-FDG molecule and by a better spatial resolution of coincidence imaging in comparison to a conventional gamma camera.

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