background: this work investigated the dosimetry limitations of the random and systematic uncertainties of sliding window (sw) intensity modulated radiation therapy (imrt). materials and methods: a varian 21ex linear accelerator, pinnacle3 treatment planning system and radiographic film dosimetry was used. the limitations of the sw were studied using beam modulation ranging from 2 to 100 mu/bea...

introduction evaluation of the delivered dose of externally wedged photon beams by external diode dosimeters during the treatment process requires the estimation of exit surface dose correction factors in various wedge angles and field sizes. materials and methods a system of absorbed dose evaluation, using p-type diode dosimeters placed on the exit surface of a phantom, was characterized for e...

Introduction Evaluation of the delivered dose of externally wedged photon beams by external diode dosimeters during the treatment process requires the estimation of exit surface dose correction factors in various wedge angles and field sizes. Materials and Methods A system of absorbed dose evaluation, using p-type diode dosimeters placed on the exit surface of a phantom, was characterized for e...

background: dose calculation algorithms play a very important role in predicting the explicit dose distribution. we evaluated the percent depth dose (pdd), lateral depth dose profile, and surface dose volume histogram in inhomogeneous media using calculation algorithms and inhomogeneity correction methods. materials and methods: the homogeneous and inhomogeneous virtual slab phantoms used in th...

ABSTRACT Background: In vivo measurements of applied dose during radiotherapy treatment, is important to ensure accurate dose delivery to patients. Uncertainty in dose delivery should fall within ±5% of the prescribed dose as recommended by ICRU. Assessment of dose for radiotherapy applications performed with various types of detectors. In this study, semiconductor diodes were used which have s...

background: total body irradiation (tbi) is different from standard radiotherapy in many aspects, so it is not easy to predict the delivered dose to the patient under tbi treatment. diode dosimetry procedures for surface dose reading can help to define variations of the actually delivered dose from the prescribed one. the aim of this study was to describe the measurements made to calibrate diod...

abstract background: in vivo measurements of applied dose during radiotherapy treatment, is important to ensure accurate dose delivery to patients. uncertainty in dose delivery should fall within ±5% of the prescribed dose as recommended by icru. assessment of dose for radiotherapy applications performed with various types of detectors. in this study, semiconductor diodes were used which have s...

background: use of contrast agents (cas) during ct simulation for treatment planing system leads to changes in  electron density. in this study we aimed to investigate the effect on  calculated dose of various concentrations of cas on treatment planing systems in different dose calculation algorithms. materials and methods: contrast agent (0.769 mg/ml iopromid) - water mixtures at concentration...

Background: Use of contrast agents (CAs) during CT simulation for treatment planing system leads to changes in  electron density. In this study we aimed to investigate the effect on  calculated dose of various concentrations of CAs on treatment planing systems in different dose calculation algorithms. Materials and Methods: Contrast agent (0.769 mg/ml Iopromid) - water mixtures at con...

introduction: esophageal cancer is one of the most frequently occurring cancers in iran and having a  high  incidence  rate  among  other  countries.  radiotherapy  is  one  of  the  three  methods  (surgery,  radiotherapy and chemotherapy) for radical or palliative treatment of esophageal cancer. in this method  of treatment, the organs such as heart and spinal cord are regarded as organs at r...