Background: To reduce the dose to normal tissues surrounding the treated breast, a uniform magnetic field was used within a humanoid phantom in breast radiotherapy. Materials and Methods: Monte Carlo simulations were performed with GEANT4, irradiating humanoid phantoms in a magnetic field. To reconstruct phantoms, computed tomography (CT) data slices of four patients were used for the Monte Car...

introduction magnetic fields are capable of altering the trajectory of electron beams andcan be used in radiation therapy.theaim of this study was to produce regions with dose enhancement and reduction in the medium. materials and methods the ndfeb permanent magnets were arranged on the electron applicator in several configurations. then, after the passage of the electron beams (9 and 15 mev va...

Background: Anopheles stephensi is considered to be the main malaria vector in the Middle East area including Iran. We aimed to evaluate the efficiency of a granule 10% formulation of Bacillus thuringiensis against this species under laboratory and semi-field conditions in an endemic malarious area of Iran. Method: After collecting mosquitos ...

introduction: in recent decades, several monte carlo codes have been introduced for research and medical applications. these methods provide both accurate and detailed calculation of particle transport from linear accelerators. the main drawback of monte carlo techniques is the extremely long computing time that is required in order to obtain a dose distribution with good statistical accuracy. ...

background: monte carlo method (mc) has played an important role in design and optimization of medical linacs head and beam modeling. the purpose of this study was to compare photon beam features of two commercial linacs, varian 21ex and elekta sl-25 using mcnp4c mc code. materials and methods: the 6mv photon beams of varian 21ex and elekta sl-25 linacs were simulated based on manufacturers pro...

background: an effective method for management of large and bulky malignant tumors. this treatment modality is also known as specially fractionated radiation therapy (sfrt). in this treatment technique a grid block converted the open radiation field into a series of pencil beams. dosimetric characteristics of an external beam grid radiation field have been investigated using experimental and mo...

Introduction: Breast cancer is one of the most common known cancers in women all around the world. It is the most common cause of death in women after lung cancer. Radiotherapy is a method for therapy of cancer in which certain dose of high energy radiations is used to destruct cancer cells. Radiotherapy is designed so that radiation of eartain does to the target area in body i...

Background: The electron contamination may reduce or even diminish the skin sparing property of the megavoltage beam. The detailed characteristics of contaminant electrons are presented for different field sizes and cases. Materials and Methods: The Monte Carlo code, MCNPX, has been used to simulate 18 MV photon beam from a Varian Linac-2300 accelerator. All dose measurements were car...

Background: For radiotherapy of total skin including sub-cutaneous tissue up to a depth of 3 cm on the entire left leg of an adult (Angiosarcoma skin), a complex treatment with multiple stationary electron fields was planned at our clinic. The details of dosimetry, clinical dose measurements are presented. Materials and Methods: The treatment planned with 6 overlapping 9 MeV electron fields in ...

Introduction: Irregular/blocked fields are routinely used in radiotherapy. The doses of these fields are usually calculated by means of equivalent square method that is inherently prone to uncertainty. On the other hand, Clarkson’s sector integration method is a dose calculation method which offers far better accuracy in dose calculation of irregular fields. The Scatter Air Ratio (SAR) of an in...