introduction: nowadays new radiochromic films have an essential role in radiotherapy dosimetry. properties such as high sensitivity, good reproducibility, high spatial resolution, easy readout and portability have made them attractive for dosimetry, especially in high-dose-gradient regions. material and methods: in this study, electron-beam dose distributions in homogenous and heterogeneous pha...

Introduction: Intraoperative radiotherapy is a radiotherapy technique in which a high single fraction of radiation dose is delivered to the patient after surgery and Concurrent with anesthesia time. The most frequent method for IORT implementation is Intraoperative electron radiotherapy (IOERT), in which, some dedicated and high dose per pulse electron accelerators are employe...

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 ...

background: the purpose of this study was to investigate the application of the monte carlo technique to calculate and analysis of dosimetric parameters for electron beams used in radiotherapy. this technique is based on statistical method and has a powerful role in different radiotherapy aspects. materials and methods: the simulated medical linear accelerator was the varian clinac 2100c. the e...

PURPOSE To calculate the output factor (OPF) of any irregularly shaped electron beam at extended SSD. METHODS Circular cutouts were prepared from 2.0 cm diameter to the maximum possible size for 15 × 15 applicator cone. In addition, two irregular cutouts were prepared. For each cutout, percentage depth dose (PDD) at the standard SSD and doses at different SSD values were measured using 6, 9, ...

BACKGROUND AND PURPOSE To elaborate a method for applicator reconstruction for MRI-based brachytherapy for cervical cancer. MATERIALS AND METHODS Custom-made plastic catheters with a copper sulphate solution were made for insertion in the source channels of MR-CT compatible applicators: plastic and titanium tandem ring applicators, and titanium needles. The applicators were CT and MR scanned ...

Introduction: Intraoperative electron radiotherapy (IOERT) is an IORT technique in which electron beams with different nominal energies are used for irradiation of microscopic residual of tumor bed after surgery. Application of a shielding disk, which is positioned under the target volume, for protecting the normal tissues such as pectoral muscle, lung, and heart is one of the a...

Currently, patients having cervical cancer with extension into the lower vagina are being treated with a combination of the Fletcher-Suit applicator, which treats the cervix, and a vaginal cylinder, which treats the lower vagina. With this method, patients receive two separate implants-a procedure that creates greater uncertainty in the dose distribution and unnecessary patient inconvenience. T...

A major task in commissioning an electron accelerator is to measure relative output factors versus cutout size (i.e., cutout factors) for various electron beam energies and applicator sizes. We use the BEAM Monte Carlo code [Med Phys. 22, 503-524 (1995)] to stimulate clinical electron beams and to calculate the relative output factors for square cutouts. Calculations are performed for a Siemens...

High dose rate (HDR) brachytherapy is one of the accepted treatment modalities in gastro-intestinal tract and bladder carcinomas. Considering the shortcoming of contact brachytherapy routinely used in gastrointestinal tract in treatment of big tumors or invasive method of bladder treatment, an intraluminal applicator with the capability of insertion into the tumor depth seems to be useful. This...