A standard protocol of dosimetric measurements is used by the organizations responsible for verifying that the doses delivered in radiation-therapy institutions are within authorized limits. This study evaluated a self-designed simple auditing phantom for use in verifying the dose of radiation therapy; the phantom design, dose audit system, and clinical tests are described. Thermoluminescent do...

Introduction: The aim of this work was to assess Dixon-based MRI techniques for fat quantification in the calf muscle at 3T. It has been reported in the literature that a strong correlation (r=0.96) exists between 3-point Dixon (3PD) and known concentrations of fat and water in a phantom study at 1.5T [1] and strong correlation (r2=0.985) between 3PD and MRS in a phantom study at 3.0T [2]. In t...

Our institution delivers TBI using a modified Theratron 780 60Co unit. Due to limitations of our treatment planning system in calculating dose for this treatment, we have developed a fast Monte Carlo code to calculate dose distributions within the patient. The algorithm is written in C and uses voxel density information from CT images to calculate dose in heterogeneous media. To test the algori...

Introduction: Accelerated Partial Breast Irradiation (APBI) is an effective treatment for breast carcinomas because of its limited number of fractions. Strut-adjusted volume implant (SAVI) is a HDR brachytherapy applicator to deliver the prescription dose with good PTV coverage and acceptable dose to skin, chest wall and organ at risks. Acceptable clinical outcomes depend on a...

Background: Accurate dose calculations in small beamlets and lung material have been a great challenge for most of treatment planning systems (TPS).  In the current study, the dose calculation accuracy of TiGRT TPS was evaluated for small beamlets in water and lung phantom by comparison to Monte Carlo (MC) calculations. Materials and Methods: The head of Siemens Oncor-impression linac...

When multiple scanners are used to acquire diffusion MR image data from the same patient (even on the same day), there is no guarantee that identical settings will result in comparable images of a specific organ and region. Despite this, for clinical use, any software developed to compute the apparent diffusion coefficient (ADC) must be expected to give equivalent results. What is needed is a p...

This study evaluated the dosimetric impact of surface dose reduction due to the loss of backscatter from the bone interface in kilovoltage (kV) X-ray radiation therapy. Monte Carlo simulation was carried out using the EGSnrc code. An inhomogeneous phantom containing a thin water layer (0.5-5 mm) on top of a bone (thickness = 1 cm) was irradiated by a clinical 105 kVp photon beam produced by a G...

conclusions by a simple check of the water peak characteristics, lots of information can be obtained, one of which is the status of shimming that has a considerable effect on the accuracy of the spectrum. thus, performing an automatic or manual shimming is not a criterion of the spectrum accuracy, and performing a periodic quality control using a test phantom by a specialist is necessary. brief...

AIM The aim of the paper is to examine the relation between the increase of the photon dose in water in the region of electronic disequilibrium - so-called build-up region - and the distance of the bolus from the water surface for the applied parameters of X-ray beams. MATERIALS AND METHODS PDD measurements were carried out using the plane-parallel ionization chamber Markus in the automatic w...

introduction:  90 sr/ 90 y source  has  been  used  for  the  intravascular  brachytherapy  to  prevent  coronary  restenosis in the patients who have undergone angioplasty. the aim of this research is to determine the  dose distribution of  90 sr/ 90 y source in a water phantom.  materials  and  methods:  in  the  present  work,  mcnp  code  has  been  applied  to  calculate  the  dose  distri...