background: the presence of a wedge filter in the beam trajectory can modify the beam quality and cause some changes in the dosimetry parameters which are usually difficult to be measured directly and accurately. material and methods: in this study the mcnp-4c monte carlo code was used to simulate the 9 mv photon beam generated by a linear accelerator. upon getting a good agreement between the ...

background: physical wedges are still widely used as beam modifiers in external beam radiotherapy. however the presence of them in the beam trace may cause beam hardening which may not be considered in many treatment planning systems. the aim of this study is to investigate the beam hardening effect generated by physical wedges via different beam quality indexes as photon spectrum, half value l...

Dynamic wedges have been used in clinical practice for many years. Obvious superiority of dynamic over physical wedges is accompanied by the increased overhead involved in verifying the accuracy and reliability of their use. Contrary to very limited QA required to ensure proper functioning of the physical wedges, dynamic wedges, like any other dynamic treatment, require a robust QA program. Thi...

[1] Even though the rheology of thrust wedges is mostly frictional, a basal ductile decollement is often involved. By comparison with purely frictional wedges, such brittleductile wedges generally display anomalous structures such as backward vergence, widely spaced thrust units, and nonfrontward sequences of thrust development. Laboratory experiments are used here to study the deformation of b...

Background: The presence of a wedge filter in the beam trajectory can modify the beam quality and cause some changes in the dosimetry parameters which are usually difficult to be measured directly and accurately. Material and Methods: In this study the MCNP-4C Monte Carlo code was used to simulate the 9 MV photon beam generated by a linear accelerator. Upon getting a good agreement bet...

Background: Physical wedges are still widely used as beam modifiers in external beam radiotherapy. However the presence of them in the beam trace may cause beam hardening which may not be considered in many treatment planning systems. The aim of this study is to investigate the beam hardening effect generated by physical wedges via different beam quality indexes as photon spectrum, half value l...

This paper proposes a simple method for guiding researchers in developing quantitative models of economic fluctuations. We show that a large class of models, including models with various frictions, are equivalent to a prototype growth model with time varying wedges that, at least on face value, look like time-varying productivity, labor taxes, and capital income taxes. We label the time varyin...

We obtain lower bounds in the algebraic computation tree model for deciding the separability of two disjoint point sets. In particular, we show Ω(n log n) time lower bounds for separability by means of strips, wedges, wedges with apices on a given line, fixed-slopes double wedges, and triangles, which match the complexity of the existing algorithms, and therefore prove their optimality.