Impact of the various kVp settings used during computed tomography (CT) simulation that provides data for heterogeneity corrected dose distribution calculations in patients undergoing external beam radiotherapy with either high-energy photon or electron beams have been investigated. The change of the Hounsfield Unit (HU) values due to the influence of kVp settings and geometrical distribution o...

The purpose of this study was to empirically characterize and validate a kilovoltage (kV) X-ray beam source model of a superficial X-ray unit for relative dose calculations in water and assess the accuracy of the British Journal of Radiology Supplement 25 (BJR 25) percentage depth dose (PDD) data. We measured central axis PDDs and dose profiles using an Xstrahl 150 X-ray system. We also compare...

Background: Much research has widely been conducted into thyroid hormones levels following radiotherapy for breast cancer. Consequently, in this study, we evaluated to relate the rate of thyroid hormones levels with the dose distribution among breast cancer patients.Material and Methods: Thirty patients were treated with 4-field breast cancer radiotherapy. The dose volume histograms, the volume...

The present study compared the dose-volume histograms of patients with Stage IIIA non-small cell lung cancer (NSCLC) treated with carbon ion radiotherapy with those of patients treated with X-ray radiotherapy. Patients with Stage IIIA NSCLC (n = 10 patients for each approach) were enrolled. Both radiotherapy plans were calculated with the same targets and organs at risk on the same CT. The trea...

Introduction: In radiotherapy treatment planning system (TPS), basic input is the data from computed tomography (CT) scan, which takes into account the effect of inhomogeneities in dose calculations. Measurement of CT numbers may be affected by scanner-specific parameters. Therefore, it is important to verify the effect of different CT scanning protocols on Hounsfield unit (HU) and its impact o...

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...

OBJECTIVE The aim of this study is to evaluate the effect of tissue composition on dose distribution in electron beam radiotherapy. METHODS A Siemens Primus linear accelerator and a phantom were simulated using MCNPX Monte Carlo code. In a homogeneous cylindrical phantom, six types of soft tissue and three types of tissue-equivalent materials were investigated. The tissues included muscle (sk...

Introduction: Whole breast radiotherapy after breast-conserving surgery decrease the risk of local recurrence. this study investigates the dosimetric aspects of intensity modulated radiotherapy (IMRT) compared to conventional tangential wedge-based beams techniques (CTT) of the whole breast in early stages breast cancer patients.   Materials and Methods: Co...

In the present work WRF model is used to generate meteorological fields for the HYSPLIT dispersion model. Sensitivity and validation of the WRF model, is conducted by utilizing different combinations of physical parameterization schemes. For this purpose, eight different configurations are examined. Assessment of the predictions of the WRF model is carried out by computing the statistical param...

Image-guided radiation therapy using a gold marker-based tumor tracking technique provides precise patient setup and monitoring. However, the marker consists of high-Z material, and the resulting scattered rays tend to have adverse effects on the dose distribution of radiotherapy. The purpose of this study was to evaluate the dosimetric perturbation due to the use of a gold marker for radiother...