نتایج جستجو برای: pixelated collimator
تعداد نتایج: 3420 فیلتر نتایج به سال:
An electron collimator composed of a point-like source and a parabolic pn junction is proposed as a generator of highly focused electron beams in graphene. The collimator is based on negative refraction and Klein collimation, which are unique to pseudo-relativistic Dirac materials. The electron beams generated by the lensing apparatus can be steered by a weak magnetic field without losing colli...
background: obtaining high quality images in single photon emission tomography (spect) device is the most important goal in nuclear medicine. because if image quality is low, the possibility of making a mistake in diagnosing and treating the patient will rise. studying effective factors in spatial resolution of imaging systems is thus deemed to be vital. one of the most important factors in sp...
A pixelated silicon detector, developed originally for particle physics experiments, was used a beam profile measurement of cobalt-60 (Co-60) irradiator in water phantom. The compared to measured with pinpoint ionization chamber. differences the pixel detector and chamber relative profiles were within approximately 2% maximum, after calculating correction factors Monte Carlo simulations maximum...
Introduction: The Monte Carlo simulation is used to enhance reliability in the experiments related to nuclear instruments. in addition, that is used to calculate the different components of the neutron and gamma ray fluxes in boron neutron capture therapy(BNCT) and neutron capture (NCT)applications. BNCT is one of the methods in radiotherapy, that is used the neutron beam for ki...
Tantalum-178 is a short-lived radionuclide (Tm = 9.3 min.) and emits primarily 56to 64-keV characteristic x-rays. We have determined the imaging characteristics with this radionuclide and a large-field-of-view Anger camera. With a pinhole collimator, good spatial resolution is possible with Ta-178, although the image quality is superior with Tc-99m under comparable conditions. Spatial resolutio...
Treatment of ocular cancers using eye plaque brachytherapy is now an established medical procedure. However, current QA for these eye plaques is quite rudimentary, limiting the opportunities for precise pretumour plaque customisation. This paper proposes and experimentally validates a new technique for imaging of eye plaque dose distributions using a high-resolution pixelated silicon detector. ...
We analyzed the physical basics for design of absorbers for high energy beams of electrons and photons. Typical examples are the collimators and dump systems. In particular, we considered a collimator for usage in Cornell ERL project, where it could be used for reduction of γ , − e halo, minimization of exposure SRF module to SR from neighboring bending magnet and for absorption of direct beam ...
The American Association of Physicists in Medicine Task Group 36 (AAPM TG-36) data can be used to estimate peripheral dose (PD) distributions outside the primary radiation field. However, the report data does not apply to linear accelerators equipped with a multileaf collimator (MLC) and universal wedge (UW). Tertiary multileaf collimators have been shown to significantly affect PD distribution...
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