background: the shielding methods in radiotherapy due to delivering an accurate radiation dose to cancer tissues and avoiding unnecessary dose to normal tissues are very important. these methods include lead standard blocks, individual molding and multi leaf collimator (mlc). the mlc method is not still common in iran radiotherapy centers. individual molding is better than the lead block shield...

background: monte carlo method (mc) has played an important role in design and optimization of medical linacs head and beam modeling. the purpose of this study was to compare photon beam features of two commercial linacs, varian 21ex and elekta sl-25 using mcnp4c mc code. materials and methods: the 6mv photon beams of varian 21ex and elekta sl-25 linacs were simulated based on manufacturers pro...

Background: Monte Carlo method (MC) has played an important role in design and optimization of medical linacs head and beam modeling. The purpose of this study was to compare photon beam features of two commercial linacs, Varian 21EX and Elekta SL-25 using MCNP4C MC code. Materials and Methods: The 6MV photon beams of Varian 21EX and Elekta Sl-25 linacs were simulated based on manufacturers pro...

A algorithm of obtaining absolute dose at each tissue depth only by the mathematical calculation formula is reported. The based on integrating energy flux electron generated X-ray in range irradiation field, and spectrum ray secondary scattered are considered this process. In algorithm, water phantom field divided into several thin layers, electrons interaction between layer reaching point calc...

Introduction: A dosimetric audit is a quality assurance process (QA) that allows the accuracy of dosimetric and geometric precision to accurately control the delivery of doses. They can be used to evaluate the accuracy of radiation delivery at different radiotherapy centers. Differences in prescriptive doses, depending on the severity of the differences, have potential conseque...

background: the dose rate distribution delivered by a low dose rate 137cs pellet source, a spherical source used within the source trains of the selectron gynecological brachytherapy system, was investigated using the mcnp4c monte carlo code. materials and methods: the calculations were performed in both water and plexiglas and the absolute dose rate distribution for a single pellet source and ...