background: in treating patients with radiation, the degree of accuracy for the delivery of tumor dose is recommended to be within ± 5% by icru in report 24. the experimental studies have shown that the presence of low-density inhomogeneity in areas such as the lung can lead to a greater than 30% change in the water dose data. therefore, inhomogeneity corrections should be used in treatment pla...

introduction: in brachytherapy, radioactive sources are placed close to the tumor, therefore, small changes in their positions can cause large changes in the dose distribution. this emphasizes the need for computerized treatment planning. the usual method for treatment planning of cervix brachytherapy uses conventional radiographs in the manchester system. nowadays, because of their advantages ...

monte carlo method is a very accurate method to optimize medical diagnostic radiology spectra and simulation of radiation transportation. using mcnp code, radiology and mammography attenuated x-rayspectraweresimulated.the ipem report number 78 was used as a reference to compare with the geant4 and mcnp simulations because of its popularity and wide availability. the results of geant4 in 40kev s...

With the advent of inexpensive computing power over the past two decades, applications of Monte Carlo radiation transport techniques have proliferated dramatically. At Los Alamos, the Monte Carlo codes MCNP5 [1] and MCNPX [2] are used routinely on personal computer platforms for radiation shielding analysis and dosimetry calculations. These codes are attractive for such applications because of ...

A new algorithm for energy-loss straggling in MCNP is demonstrated. An approximate but accurate energy-loss moment-preserving differential cross section is used in conjunction with single event Monte Carlo simulation through each condensed history step to show that highly accurate energy spectra, leakage currents, and dose profiles can be obtained. This new approach provides a viable and even p...

background: obtaining high quality images in single photon emission tomography (spect) device  is the most important goal in nuclear medicine. because if image quality is low, the possibility of making a mistake in diagnosing and treating the patient will rise. studying effective factors in spatial resolution of imaging systems is thus deemed to be vital. one of the most important factors in sp...

Background: Monte Carlo and experimental relative dose determination in a water phantom, due to a high dose rate (HDR) 192Ir source is presented for real energy spectrum and monochromatic at 356 keV. Materials and Methods: The dose distribution has been calculated around the 192Ir located in the center of 30 cm ×30 cm ×30 cm water phantom using MCNP4C code by Monte Carlo method. Relati...

The dose calculation accuracy of a commercial pencil beam IMRT planning system is evaluated by comparison with Monte Carlo calculations and measurements in an anthropomorphic phantom. The target volume is in the right lung and mediastinum and thus significant tissue inhomogeneities are present. The Monte Carlo code is an adaptation of the MCNP code and the measurements were made with TLD and fi...

Pohang Neutron Facility (PNF) is a pulsed neutron facility based on the 100-MeV electron linear accelerator. It was constructed for nuclear data production in Korea, and it consists of an electron linear accelerator, a watercooled Ta target with a water moderator and a time-offlight path with an 11 m length. The 100-MeV electron linac uses a thermionic RF-gun, an alpha magnet, four quadrupole m...

Pohang Neutron Facility (PNF) is a pulsed neutron facility based on the 100-MeV electron linear accelerator. It was constructed for nuclear data production in Korea, and it consists of an electron linear accelerator, a watercooled Ta target with a water moderator and a time-offlight path with an 11 m length. The 100-MeV electron linac uses a thermionic RF-gun, an alpha magnet, four quadrupole m...