eLearning

GEANT4 simulations and experimental measurements of absolute source activity using modified sum-peak method

M. Dhibar; I. Mazumdar; G. Anil Kumar 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2015

In the present work, we have made Monte Carlo simulations of the response of 1" × 1" LaCb(Ce) and 1" × 1" LaBn(Ce) scintillation detectors using the radioactive sources emitting two gamma rays in cascade, namely, 60Co, 94Nb, 46Sc and 24Na for different values of source-detector separation. These simulations were done using GEANT4 toolkit that include radioactive decay module and ...

Bayesian Image Reconstruction for the Clear-PEM scanner

M. V. Martins; A. Trindade; N. Matela; N. Oliveira; H. Cordeiro; P. Rodrigues; N. C. Ferreira; J. Varela; P. Almeida 2006 IEEE Nuclear Science Symposium Conference Record, 2006

The Clear-PEM scanner, a device based on a two-head planar detector, is currently being developed for positron emission mammography under the framework of the Crystal Clear Collaboration. Previously, we reported the introduction of new features into the STIR library, allowing its use with Clear-PEM simulated data. Previous reports indicate that image reconstruction of cylindrical PET data using Bayesian reconstruction methods ...

The Use of Accelerators for the Study of Delayed Neutrons from Fission; Significance to Reactor Control

J. Walker; D. R. Weaver; J. G. Owen IEEE Transactions on Nuclear Science, 1981

Delayed neutrons from fission are very important in the kinetic behaviour of nuclear reactors and in the assaying of nuclear materials. Information is necessary on lifetimes, yields, and energies, and the paper shows the part which accelerators have played in providing it. Special attention is paid to yields and to recent measurements of delayed-neutron energies in fast fission; attention is ...

A new preprocessor for the SP-3000 series of time-of-flight positron emission tomographs

T. K. Lewellen; S. G. Kohlmyer; D. C. Ehlert; R. M. Miyaoka IEEE Transactions on Nuclear Science, 1993

A new preprocessor for the University of Washington modified SP-3000 positron emission tomograph was designed and built. The device improves the maximum coincidence counting rate of the machine to greater than 450000 events per second in preprocessed mode. The new hardware also improves image quality by implementing time-of-flight offset corrections by crystal pairs, position and time-of-flight gating for the rotating ...

Development of a daily quality check procedure for the high resolution research tomograph (HRRT) using natural LSO background radioactivity

C. Knoess; T. Gremillion; M. Schmand; M. E. Casey; L. Eriksson; M. Lenox; J. T. Treffert; S. Vollmar; G. Fluegge; K. Wienhard; W. -D. Heiss; R. Nutt 2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310), 2001

A daily quality check (DQC) plays an important role for clinical medical systems like a Positron Emission Tomograph (PET). To guarantee image quality a constant monitoring of the scanner integrity is essential. On present PET scanners the built-in transmission sources are being used for the measurement of a uniform blank scan and the computation of detector-block efficiencies. These efficiencies can ...

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IEEE-USA E-Books

• Nuclear Medicine

  This chapter contains sections titled: General Principles of Nuclear Medicine Radioactivity The Production of Radionuclides Types of Radioactive Decay The Technetium Generator The Biodistribution of Technetium-Based Agents within the Body Instrumentation: The Gamma Camera Image Characteristics Single Photon Emission Computed Tomography Clinical Applications of Nuclear Medicine Positron Emission Tomography This chapter contains sections titled: Exercises Further Reading

• Fundamentals of Electrical Discharges

  Natural phenomena, such as gamma rays produced by radioactive decay processes in the soil and cosmic radiation originating from solar flares and other galactic objects, can ionize the air molecules. This chapter first discusses ionization and deionization processes in gases. This is followed by a discussion on ionization and attachment coefficients. Two typical breakdown mechanisms occur in gases, each of them operating under specifically favorable conditions: Townsend's mechanism and the streamer mechanism. Corona discharges in air can burn on the overstressed zones of hot electrodes. This kind of discharge occupies a short layer, attached to the energized conductor. When a conductor is in corona, then the electric field on the surface is somehow influenced by the surrounding ion space charge. Kaptzov's hypothesis (KH) relates to the assumption that the space charge emitted into the interelectrode gap is in amounts that hold the surface field at the onset level.