The design of a radiotherapy treatment includes the selection of beam angles (geometry problem), the computation of a fluence pattern for each selected beam angle (intensity problem), and finding a sequence of configurations of a multilef collimator to deliver the treatment (realization problem). While many mathematical optimization models and algorithms have been proposed for the intensity pro...

the aim of this study is to provide a control software system, based on monte carlo simulation, and calculations of dosimetric parameters of standard and wedge radiation fi elds, using a monte carlo method. gate version 6.1 (opengate collaboration), was used to simulate a compact 6 mv linear accelerator system. in order to accelerate the calculations, the phase-space technique and cluster compu...

Introduction The ZAP-X is a novel self-contained and first-of-its-kind self-shielded therapeutic radiation device dedicated to brain and head and neck radiosurgery. By utilizing a 2.7-MV linear accelerator and incorporating a design in which a beam stop and major mechanical elements serve a radiation shielding function, the Zap-X does not typically require a radiation bunker. The unique collima...

The analysis of a slitless volume holographic spectrometer is presented in detail. The spectrometer is based on a spherical beam volume hologram followed by a Fourier-transforming lens and a CCD. It is shown that the spectrometer is not sensitive to the incident angle of the input beam for the practical range of applications. A holographic spectrometer based on the conventional implementation i...

In order to have highly flexible secondary beamlines collimation is crucial. Collimators are blocks of material placed along the beamline that let main beam pass within collimator aperture limits, while most particles beyond it interact in and gets absorbed or loses enough energy be deflected away from core by magnets downstream. Some can at edge collimators accepted beam, creating background f...

A rotatable collimator is proposed for the LHC phase II collimation upgrade. When the beam crosses the collimator, it will excite trapped modes that can contribute to the beam energy loss and power dissipation on the vacuum chamber wall. Transverse trapped modes can also generate transverse kicks on the beam and may thus affect the beam quality. In this paper, the parallel eigensolver code Omeg...

We assessed improvements in performance in detection and estimation tasks due to a novel brain single photon computed tomography collimator. Data were acquired on the CeraSPECT scanner using both new and standard collimators. The new variable focusing collimator SensOgrade samples the projections unequally, with central regions more heavily represented, to compensate for attenuation of counts f...

Tomographic imaging of the brain was performed using a rotating slant hole collimator and [123I]N-isopropyl p-iodoamphetamine (IMP) in normal subjects (n = 6) and patients with either Alzheimer's disease (n = 5) or multiple infarct dementia (n = 3). Four blinded observers were asked to make a diagnosis from the images. Normal subjects and patients with multiple infarct dementia were correctly i...

The experiment was also made of crossing the spectra at some other angle than 0° or 180°. For instance, the rulings of the Ives grating were placed at right angles to those of the interferometer grating, as in Newton's method of crossed prisms. Seen in the telescope (adjusted for inverted spectra) the two spectra now made an elbow with each other, while the D1 DA lines were still parallel and c...