background: exposure conditions in ct examinations are quite different from conventional xray. in ct examination higher dose is given to patient in comparison with the dose in other diagnostic examinations. in order to calculate organ effective dose in chest ct, monte carlo simulation has been used in this study. materials and methods: the impact survey data were used to determine the parameter...

background: polymer gel dosimetry is still the only dosimetry method for direct measuring of threedimensional dose distributions. mri polymer gel dosimeters are tissue equivalent and can act as a phantom material. in this study the obtained isodose maps with pagat polymer gel dosimeter were compared to those calculated with egsnrs for singleshot irradiations of 8 and 18 mm collimators of gamma ...

Introduction: Brachytherapy is one type of internal radiation therapy where radiation sources, which are usually encapsulated, are placed as close as possible to the tumor site or inside the patient's body. In this technique, it is important to determine dose distribution around the brachytherapy capsule to create optimal treatment plant. In this way, dosimetric parameters are...

We introduce a fast and well-structured package for constructing voxel-based computational phantoms as MCNP(X) input file based on CT DICOM images. Our program which has been implemented under a graphic user inter-face provides several basic image processing tools for manipulating images. The MCNP materials are interpreted from the CT numbers of DICOM images. Two modes of phantom creation have ...

In calculations for the Leksell Gamma Knife, GammaPlan employs a tissue equivalent material without the presence of a skull bone, while dosimetry work is based on a polystyrene phantom. The compatibility of these dose distributions is uncertain. The Monte Carlo technique was employed to determine the radial dose distributions from a single 14 mm collimator helmet in 160 mm diam phantoms with di...

Dosimetry calculations characterizing the spatial variation of the energy deposited by the slowing and stopping of energetic electrons are reported and compared with experimental measurements from an electron microbeam facility. The computations involve event-by-event, detailed-histories Monte Carlo simulations of low-energy electrons interacting in water vapor. Simulations of electron tracks w...

The solid-state nuclear track detector CR-39 is widely used as a detecting mechanism in physics experiments as well as for industrial purposes such as neutron dosimetry and radon detection. The upper limit of detectable charged-particle fluence on CR-39 is set by physical overlapping or ‘pulse pileup’ of particle tracks on the surface. In the low-overlap regime the overlapping fraction of track...

Thoracic cancer treatment presents dosimetric difficulties due to respiratory motion and lung inhomogeneity. Monte Carlo and deformable image registration techniques have been proposed to be used in four-dimensional (4D) dose calculations to overcome the difficulties. This study validates the 4D Monte Carlo dosimetry with measurement, compares 4D dosimetry of different tumor sizes and tumor mot...

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 with various energies of radiation using water s...