نتایج جستجو برای: virtual wedge
تعداد نتایج: 158550 فیلتر نتایج به سال:
Introduction: Nowadays radiotherapy plays an important role in cancer treatment. Different radiotherapy techniques improvement emphasizes on using of the precise ، appropriate and useful algorithms. one of these techniques are wedged which is used in radiotherapy to compensate missing tissues and create a uniform dose distribution in tissues. The Siemens Artiste linear accelera...
Siemens Virtual Wedge factor may drift significantly due to increase in output as dose rate decreases. This variation of output is caused by defective sample and hold boards in the dosimetry circuit due to radiation damage. In this note, we present a simple model based on the principle of Virtual Wedge operation and the measured output variation with dose rate to quantitatively describe Virtual...
A non-physical wedge generates a spatial dose distribution similar to that produced by a physical wedge without a physical filter in the photon beam. Instead, an exponential fluence profile is produced via motion of one of the collimating jaws. Proposed in the late 1970s, nonphysical wedges have been implemented on both Varian and Siemens’ accelerators as the Varian Dynamic Wedge (DW) and Sieme...
We describe the history and construction of a stereoscopic projection theatre known as the Wedge. Originally built as a means to introduce supercomputer level visualization facilities into a cash-strapped Australian university, the Wedge has attracted some thousands of visits from the general public. Wedges can now be found in two Australian universities and two museums (visitor centres). Recen...
The virtual source technique, which is based on the boundary integral method, provides the means to impose boundary conditions on arbitrarily shaped boundaries by replacing them by a collection of sources whose amplitudes are determined from the boundary conditions. In this paper the virtual source technique is used to model propagation of waves in a range-dependent ocean overlying an elastic b...
Estimation of the possible instability that may be encountered in the excavation slope(s) during the planning and application steps of the rock excavation processes is an important issue in geoengineering. In this paper, a modelling method is presented for assessing the probability of wedge failure involving new permanent or temporary slope(s) along the planned excavation dir...
A new method of generating wedge-shaped dose distributions through dynamic multileaf collimator dose delivery rather than computer-controlled jaw motion is presented. The method starts with the calculation of a wedge-shaped beam profile for the desired wedge angle. The resultant wedge beam profile is then passed to the intensity-modulated radiation therapy (IMRT) leaf sequence generation algori...
background: in radiotherapy, wedge filters are used for optimizing the tumor dose distribution in patients. the attenuation in beam intensity due to the presence of wedge filter is compensated by means of a wedge factor measured at the central axis of the beam. the field size, depth and ssd dependence of wedge factor have been assessed for 9mv radiations of neptun pc linear accelerator. materia...
To most of us, conduct wayfinding behavior within a virtual environment using a smart mobile device has become a common task in our daily life. Various visual designs together with different interaction modes are available in these smart devices. The purpose of this study is to investigate the effects of wedge visual design on user interaction mode within a 3D virtual environment. This study ad...
abstract nowadays, industries cannot play a crucial role in national and international competitions. the tourism industry is no exception. tourism industry development as the most important economic sector and income generation is one of the key challenges of economic development in the world. therefore, countries were successful that take advantage of the capabilities of tourism sector using ...
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