نتایج جستجو برای: collimator detector response
تعداد نتایج: 1033857 فیلتر نتایج به سال:
During the last few years, real time gamma and neutron dosimeters have been developed and semiconductor diodes are frequently used in these dosimeters. Semiconductor diodes are used to charged particle detection. For sensitizing the detector to neutrons, a converter layer is contacted on the front surfaces of them. Incident neutrons interact with the converter and produce charged particles that...
UNLABELLED In SPECT using high-energy photon-emitting isotopes, such as (131)I, parallel-hole collimators with thick septa are required to limit septal penetration, at the cost of sensitivity and resolution. This study investigated a parallel-hole collimator with cone-shaped holes, which was designed to limit collimator penetration while preserving resolution and sensitivity. The objective was ...
BACKGROUND Cardiac 123I-meta-iodobenzylguanidine (MIBG) uptake is quantified using the heart-to-mediastinum ratio (HMR) with an Anger camera. The relationship between HMR determined using D-SPECT with a cadmium-zinc-telluride detector and an Anger camera is not fully understood. Therefore, the present study aimed to define this relationship using images derived from a phantom and from patients....
Practical quantitative measurement of graticule misalignment relative to collimator axis of rotation
We design a practical procedure for measuring translational and rotational misalignment of graticule with collimator axis of rotation and collimator jaws, respectively. The procedure's quantitative results are accurate to less than 0.2 mm (at isocenter) and do not assume alignment of radiation focal spot with collimator axis of rotation. When provided with these quantitative results, the manufa...
In this project the neutron spectra from the reaction of deutron on beryllium muclei is measured. The energies of deuterons were 7, 10, 13 and 15 MeV, and these measurements are performed at 10, 30 and 50 degrees relative to the beam of deutrons. The detector used is 76 by 76 mm right circular cylender of NE-213 liquid scintillator. The zero crossing technique is used for gamma discriminatin....
EGS is a very common Monte Carlo code, used in the simulation of Nuclear Medicine devices. Simulation techniques are particularly useful, in order to optimize collimator configuration and camera design in Single Photon Emission studies. Using the EGS code, users must define the geometry where particles are transported. This can be both a very hard task and a source of inefficiency, especially i...
Panther is a new high-flux medium-resolution direct-geometry thermal-neutron time-of-flight spectrometer at the Institut Laue-Langevin (ILL). It designed for inelastic neutron-scattering measurements of excitations in condensed matter using single crystals, polycrystalline samples, and liquids. uses double focusing graphite or Cu monochromators, Fermi chopper, position-sensitive 3 He detectors ...
A specially designed high resolution converging collimator having a focal length of 50 cm has been evaluated for cone beam single photon emission computed tomography (SPECT). The focal region was investigated by imaging a point source placed at the expected focal point and along the central ray of the collimator in front of and behind the focal point. Technetium-99m point source sensitivities m...
A long bore fan beam collimator for imaging the head was designed and constructed for a SPECT system with a rotating scintillation camera. In order to avoid the patient's shoulder during rotation of the camera with a thick camera housing, the long bore design is necessary to allow the collimator to get close to the patient's head for improved spatial resolution. Operating at the minimum radius ...
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