Introduction:  On  the  basis  of  percent  depth  dose  (PDD)  calculation,  the  application  of  dosimetry  in  radiotherapy  has  an  important  role  to  play  in  reducing  the  chance  of  tumor  recurrence. The aim of this study is to introduce a new formula for calculating the centeral axis  percent depth doses of Cobalt-60 beam.   Materials and Methods: In the present study, based on ...

Purpose: This study was to investigate the effect of irregularity in shape of field size of electron beam on the percentage depth dose and the output factor. Study the variety of the Percentage Depth Dose (PDD) and the output factors for rectangular and small field sizes when one of field dimensions less than the Practical Range (Rp) of the electron energy used. Compare the measured output fact...

introduction: nowadays,  considerable developments  in  the field  of  radiotherapy have  been  achieved.  they  include  the  advances  made  in  the  equipments  and  treatment  planning  techniques  which  require  highly complex calculations. such achievements have made it possible to treat cancer patients not only  with  higher  radiation  dose  but  also  with  higher  precision  and  con...

This study evaluates changes in the dosimetric characteristics of a Varian Millennium 80-leaf multileaf collimator (MLC) in a radiation field. In this study, dose rate, scatter factor, percentage depth dose, surface dose and dose in the buildup region, beam profile, flatness and symmetry, and penumbra width measurements were made for 6-MV and 15-MV photon beams. Analysis of widths between 50% d...

Background: Attenuation coefficient (μ) plays an important role in calculations of treatment planning systems, as well as determination of dose distributions in external beam therapy, dosimetry, protection, phantom materials and industry. So, its exact measurement or calculation is very important. The aim of this study was to evaluate the μ in different points in the water phantom anal...

background: the purpose of this study was to investigate the application of the monte carlo technique to calculate and analysis of dosimetric parameters for electron beams used in radiotherapy. this technique is based on statistical method and has a powerful role in different radiotherapy aspects. materials and methods: the simulated medical linear accelerator was the varian clinac 2100c. the e...

Background: Stereotactic radiosurgery is an important clinical tool for the treatment of small lesions in the brain, including benign conditions, malignant and localized metastatic tumors. A dosimetry study was performed for Elekta ‘Synergy S ’ as a dedicated Stereotactic radiosurgery unit, capable of generating circular radiation fields with diameters of 1-5 cm at isocentre using the BEAM/EGS4...

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. relative dose v...

Introduction: Intraoperative radiotherapy is a radiotherapy technique in which a high single fraction of radiation dose is delivered to the patient after surgery and Concurrent with anesthesia time. The most frequent method for IORT implementation is Intraoperative electron radiotherapy (IOERT), in which, some dedicated and high dose per pulse electron accelerators are employe...