Introduction: Nowadays,  considerable developments  in  the field  of  radiotherapy have  been  achieved.  They  include  the  advances  made  in  the  equipments  and  treatment  planning  techniques  which  require  highly complex calculations. Such achievements have made it possible to treat cancer patients not only  with  higher  radiation  dose  but  also  with  higher  precision  and  con...

introduction wedge modifiers are commonly applied in external beam radiotherapy to change the dose distribution corresponding to the body contour and to obtain a uniform dose distribution within the target volume. since the radiation dose delivered to the target must be within ±5% of the prescribed dose, accurate dose calculation by a treatment planning system (tps) is important. the objective ...

we describe a simple model that fits well with iranian economy, and extends a methodology which chary at el. (2007) demonstrated. in addition to four traditional wedges, we introduce additional trade wedge. we then evaluate the contribution of these wedges to the fluctuations in iran during last three years. because of international sanction, trading cost increases, and firms have difficulty to...

In this research, numerical simulation of a symmetric impact of a 2-D wedge, considering dynamic equations in two-phase flow is taken into account. The two-phase flow around the wedge is solved based on finite volume method and volume of fluid (VOF) scheme. The dynamic mesh model is used to simulate dynamic motion of the wedge, thereby the effects of different dynamic meshes in both structured ...

eart pressure problems are encountered in retaining walls, bulkheads, sheeting and bracing in cuts,culverts, tunnels, and cofferdams. in many cases, the lateral pressure is determined by use of classical earth pressure theories, such as coulomb's, where the equilibrium conditions of a failure wedge of soil is considered. excessive dynamic lateral earth pressure on retaining structures resu...

The expectation of a random variable is its average value, where each value is weighted according to the probability that it comes up. The expectation is also called the expected value or the mean of the random variable. For example, suppose we select a student uniformly at random from the class, and let R be the student’s quiz score. Then E [R] is just the class average —the first thing everyo...

BACKGROUND Wedge filters are commonly used in radiation oncology for eliminating hot spots and creating a uniform dose distribution in optimizing isodose curves in the target volume for clinical aspects. These are some limited standard physical wedges (15°, 30°, 45°, 60°),or creating an arbitrary wedge angle, like motorized wedge or dynamic wedge,... The new formulation is presented by the comb...

A universal wedge filter of 15W × 20 cm(2) and 60° nominal wedge angle is designed and placed between the collimating jaws and penumbra trimmers inside the treatment head. A pneumatically driven actuating mechanism toggles the wedge between the wedge IN position and wedge OUT position. The effective wedge angles were determined using an analytical formula. An accumulated wedge profile at a dept...