منابع مشابه
Dosimetric Effect Resulting From the Collimator Angle, the Isocenter Move, and the Gantry Angle Errors
Introduction: Dose distribution can be affected by diverse parameters, such as beam orientations, and collimator angles. These parameters should respect and maintain the international recommended levels during the realization of the quality assurance protocols of linear accelerators. This study aimed at evaluating the dosimetric effects on treatment quality considering...
متن کاملNumerical Calculation of Small-angle Collimator Wakefields for Short Bunches
Collimators are used to eliminate halo particles from the beam. To relax the wakefield effects a gradual transition from a large to a small aperture is used. However, the existing computer codes face severe problems for long tapered transitions. Two main sources of the problems are the grid dispersion and the staircase geometry approximation. Using recently developed time domain numerical appro...
متن کاملVariable angle photoelectron spectrometer *
The design, construction, and performance of a spectrometer for measuring the angular and energy distributions of electrons photoejected by rare gas resonance light is described. Results using 584.4-A photons from a helium lamp are reported. Flexibility of instrumental design allows for the use of other light sources. A 180° hemispherical electrostatic electron energy analyzer is rotatable abou...
متن کاملA Novel Method for Quality Assurance of the Cyberknife Iris Variable Aperture Collimator
OBJECTIVE To characterize a novel method for field-size quality assurance of a variable approximately circular aperture collimator by means of dose-area product measurements and to validate its practical use over two years of clinical application. METHODS To assess methodical limitations, we analyze measurement errors due to change in linac output, beam tuning, uncertainty in MU delivery, d...
متن کاملNeutron beam characteristics from 50 MeV protons on beryllium using a continuously variable multi-leaf collimator.
The dose distributional properties of a p(50) Be neutron beam using a continuously variable multi-leaf collimator are presented and compared with a 6 MV photon beam. The differences in physical dose delivery between these two radiation modalities are generally insignificant for radiation therapy, and stringent comparisons of neutron and photon treatments should therefore be possible. The flexib...
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ژورنال
عنوان ژورنال: Transactions of the Optical Society
سال: 1917
ISSN: 1475-4878
DOI: 10.1088/1475-4878/18/2/302