INTRODUCTION In radiotherapy, megaelectron volt (MeV) electrons are employed for treatment of superficial cancers. Magnetic fields can be used for deflection and deformation of the electron flow. A magnetic field is composed of non-uniform permanent magnets. The primary electrons are not mono-energetic and completely parallel. Calculation of electron beam deflection requires using complex mathe...

The lateral buildup ratio (LBR) used to estimate the depth dose distribution of electron beams for an irregular cutout field was obtained for a 4-MeV energy beam from a Varian 21 EX linear accelerator. The depth-dose curves for a group of circular cutout fields starting from a 2-cm diameter were measured. Electron diodes were used in a large water tank to measure the LBR values for 6, 9, 12, an...

An extendable x-ray multi-leaf collimator (eMLC) is investigated for collimation of electron beams on a linear accelerator. The conventional method of collimation using an electron applicator is impractical for conformal, modulated and mixed beam therapy techniques. An eMLC would allow faster, more complex treatments with potential for reduction in dose to organs-at-risk and critical structures...

In this work, leakage radiation from EA200 series electron applicators on Siemens Primus accelerators is quantified, and its penetration ability in water and/or the shielding material Xenolite-NL established. Initially, measurement of leakage from 10 x 10 - 25 x 25 cm2 applicators was performed as a function of height along applicator and of lateral distance from applicator body. Relative to ce...

Prototype 10 × 10 and 20 × 20-cm2 electron collimators were designed for the Elekta Infinity accelerator (MLCi2 treatment head), with the goal of reducing the trimmer weight of excessively heavy current applicators while maintaining acceptable beam flatness (±3% major axes, ±4% diagonals) and IEC leakage dose. Prototype applicators were designed initially using tungsten trimmers of constant thi...

background: intraoperative radiation therapy (iort) technique is used to treat a surgically exposed tumor or tumor bed in the treatment of locally advanced intraabdominal, retroperitoneal, pelvic, thoracic, breast and soft tissue tumors. one way to perform iort is to use an existing linac and modify the treatment head using an applicator system. in this study the objectives were to design, and ...

Introduction: One of the treatment choices in breast cancer is Intra operative electron beam radiation therapy (IOERT). Due to high dose delivery in this procedure, shielding disk is used to protect organs at risk (OARs). In this study, we evaluate the OARs dose in the breast IOERT using Monte Carlo simulation with and without shielding disk in RANDO phantom. Material and Methods: Simulation ...

Introduction: Because of importance of impact of the Source to Surface Distance (SSD) in determining of monitor unit for electron-therapy, it is essential to know the Virtual Source Position (VSP) for electron beam for a linear therapeutic accelerator for each energy and field size. , especially using the Khan method (photo distance squared method) And compare the results with...

Knowledge of the angular distribution of an electron beam at the applicator face is a necessary parameter in defining a beam when the Hogstrom pencil beam method of dose calculation is used. The angular spread can be found experimentally using penumbra widths measured at various distances from the applicator face. Using knowledge of the geometry and composition of the scattering foils of the li...

PURPOSE Intraoperative electron beam radiation therapy (IOERT) involves a modified strategy of conventional radiation therapy and surgery. The lack of specific planning tools limits the spread of this technique. The purpose of the present study is to describe a new simulation and planning tool and its initial evaluation by clinical users. METHODS AND MATERIALS The tool works on a preoperative...