Introduction: In the last few decades, a lot of monte carlo codes have been introduced for medical applications. For close - to - surface tumors, the surface of the skin can be used to increase the surface dose so that all or part of the bunch area can fall into bolus, thereby increasing the dose of the skin. The air gaps between bolus and skin can affect the dose of...

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...

In general, dose evaluation for mammography uses average glandular dose (AGD). In mammography, entrance surface dose (ESD) is high, which is well known, but actual clinical data of ESD are not reported so much. This study investigated AGD and ESD for patients whose doses were estimated from 200 mammography examinations using European Organization for Quality-Assured Breast Screening and Diagnos...

Introduction: Utilization of computed tomography (CT) scans is increasing annually. This study aimed to reduce the absorbed dose of sensitive organs in the head (eye lenses and thyroid) and to assess changes in resultant images quality in head scans when the radiation dose is decreased. Material and Methods: An anthropomorphic phantom was examined with head protocols in both helical and sectio...

background: field matching problems in abutting electron fields can be managed by using spoilers. objective: the aim of this study was to design a monte carlo framework for the assessment of spoiler application in abutting electron fields. methods: a siemens primus treatment head was simulated for a 5 mev electron beam using beamnrc and dosxyznrc, egsnrc user codes. validation of beam model was...

Introduction Accurate estimation of the skin-absorbed dose in external radiation therapy is essential to estimating the probability of secondary carcinogenesis induction Materials and Methods Electron contamination in prostate radiotherapy was investigated using the Monte Carlo (MC) code calculation. In addition, field size dependence of the skin dose was assessed. Excess cancer risk induced by...

Introduction In order to treat uveal Melanoma , first, radioactive seeds are laid on a silicone- made substance which is called Silastic after that they are inserted in the plaque, and finally, this plaque containing silicone-made substance is stitched to the sclera surface. The dose gradient within the tumor and healthy tissues can be varied due to changing the Silastic thickness between scler...

Introduction:  Skin  sparing  is  one  of  the  most  desirable  characteristics  of  high  energy  photon  beams. However, the photons emerging from the target of linacs are contaminated by secondary  electrons  as  a  result  of  their  interactions  with  air,  collimators,  flattening  filter  and  any  other  objects in their path. This phenomenon tends to increase the skin dose received b...

Background: Hot lab is a specially designed room in a nuclear medicine hospital where the radiopharmaceuticals are delivered, stored and prepared for dispensing. 99Mo/99mTc-generator is the major source in the hot lab used for various medical imaging. It is important to maintain a standard for hot lab procedures to optimize the patient care and minimize radiation exposure to all nuclear medicin...

Background Patients' dosimetry is crucial in order to enhance radiation protection optimization and to deliver low radiation dose to the patients in a radiological procedure. The aim of this study was to assess the entrance surface dose (ESD) and radiation dose to the radiosensitive organs in pediatric pelvic radiography. Materials and Methods The studied population included 98 pediatric patien...