Background: During intensity modulated radiation therapy (IMRT) technique, theoretically, presence of flattening filter (FF) across the beamline of clinical linear accelerator (linac) is not essential to obtain uniform lateral profiles due to intensity modulation of photon beams by multileaf collimators (MLCs). The aim of this study was to investigate the dosimetrical properties of 18 MV photon...

Introduction: During intensity modulated radiation therapy (IMRT) technique, theoretically, presence of flattening filter (FF) across the beamline of clinical linear accelerator (linac) is not essential to obtain uniform lateral profiles due to intensity modulation of photon beams by multileaf collimators (MLCs). The aim of this study was to investigate the dosimetrical propert...

The absorption of light in the photosynthetic process is generally believed to occur through the excitation of electrons in organic molecules to higher energy states thereby initiating a series of reactions. Recently an attempt has been made to fix the theoretical minimum quantum requirement at a number higher than that needed to obey the conservation of energy (2, 3). This argument rests on th...

All forms of microscopy that have previously been developed rely on classical sources of light, which are relatively noisy by virtue of the photons arriving randomly in time and position. We propose a new technique of two-beam optical microscopy using a nonclassical light source comprising entangled photon pairs generated by the process of nonlinear optical parametric downconversion. Entangled-...

Introduction: Physical wedge by modify photon beam shape and intensity has been utilized in radiotherapy to obtain uniformly dose distribution in tumor site with reduced hot spots. Calculation of dosimetric parameters for both symmetric and asymmetric wedged fields is proved necessary during linear accelerator (Linac) commissioning. The present study aimed to achieve o...

We report a quantum random number generator based on the photon-number-path entangled state that is prepared by means of two-photon quantum interference at a beam splitter. The randomness in our scheme is truly quantum mechanical in origin since it results from the projection measurement of the entangled two-photon state. The generated bit sequences satisfy the standard randomness test.

Objective(s): In this study we evaluate the impact of the different aspects of Gold Nano-Particles (GNPs) on the target absorptive Dose Enhancement Factor (DEF) during external targeted radiotherapy with photon beams ranging from kilovolt to megavolt energies using Monte Carlo simulation. Methods: We have simulated the interaction of photon beams wi...

PURPOSE This aim of this paper is to revisit the parallel-beam/cone-beam or fan-beam/cone-beam imaging configuration, and to investigate whether this configuration has any advantages. METHODS Twenty years ago, it was suggested to simultaneously use a parallel-beam (or a fan-beam) collimator and a cone-beam collimator to acquire single photon emission computed tomography data. The motivation w...

A quantum system can behave as a wave or as a particle, depending on the experimental arrangement. When, for example, measuring a photon using a Mach-Zehnder interferometer, the photon acts as a wave if the second beam splitter is inserted, but as a particle if this beam splitter is omitted. The decision of whether or not to insert this beam splitter can be made after the photon has entered the...

ntroduction:  Monte  Carlo  simulation  is  the  most  accurate  method  of  simulating  radiation  transport  and  predicting doses at different points of interest in radiotherapy. A great advantage of the Monte Carlo method  compared  to  the  deterministic  methods  is  the  ability  to  deal  accurately  with  any  complex  geometry.  Its  disadvantage is the extremely long computing time r...