PURPOSE To evaluate the effects of overlapping dose volumes for varying field arrangements in two formulations of PRESAGE®: one intended for, and irradiated with, proton beams and the other photon beams. METHODS For each treatment modality (photon, proton), three overlapping field setups were performed. These included a stationary dosimeter irradiated over six fractions, a dosimeter shifted l...

background: in most cancer cases, the treatment choice for a pregnant patient is radiotherapy. in these patients, the abdomen is usually not exposed therefore fetus exposure is due to peripheral dose (pd). the purpose of this study was to estimate the fetal dose (the maximum pd in each pregnancy stage) for modalities available and to fabricate and evaluate a generally applicable fetal shield. m...

The growing use of cone-beam computed tomography (CBCT) for IGRT has increased concerns over the additional radiation dose to patients. The in-field dose of IGRT and the peripheral dose (PD) from kilovoltage CBCT (KV-CBCT) imaging have been well quantified. The purpose of this work is to evaluate the peripheral dose from megavoltage CBCT (MV-CBCT) imaging for nasopharyngeal carcinoma IGRT, to d...

Introduction: Critical organs and structures may receive significant amounts of irradiation even if they are not the target of radiotherapy or located outside the treatment field. Although the sensitive thyroid gland and lens are not directly the targets of treatment, they can be affected by irradiation during the treatment of tumours in head and neck region. The purpose of thi...

Introduction: Physical wedge by modify photon beam shape and intensity has been utilized in radiotherapy to obtain uniformly dose distribution in tumor site with reduced hot spots. Calculation of dosimetric parameters for both symmetric and asymmetric wedged fields is proved necessary during linear accelerator (Linac) commissioning. The present study aimed to achieve o...

To evaluate the utility of Dynalog file information for planar dose verification in IMRT QA, a program is developed to convert Dynalog file data to DMLC field files. For this study, five predefined fluencies are planned and delivered using Varian, Eclipse 3D planning system and 6MV photon beam of Varian, Clinac DMX linear accelerator. To measure planar dose distribution, Kodak, EDR2 films are e...

abstract a field experiment was conducted at plant pest and disease research institute in karaj,iran in 2005-2006 to determine the effect of low herbicide dose of clodinafop-propargyl on percentage of wild oat control, yield and economic return of wheat. the experiment included 2 wheat varieties (rooshan and niknejad (less and more competitiveness cultivar, respectively, 4 wild oat densities (0...

introduction relative dose computation is a necessary step in radiation treatment planning. therefore, finding an approach that is both fast and accurate seems to be necessary. the purpose of this work was to investigate the feasibility of natural cubic spline to reconstruct dose maps for linear accelerator radiation treatment fields in comparison with those of the simulation. materials and met...

The purpose of the study was to investigate the use of the equivalent square formula for determining the surface dose from a rectangular photon beam. A 6 MV therapeutic photon beam delivered from a Varian Clinac 23EX medical linear accelerator was modeled using the EGS4nrc Monte Carlo simulation package. It was then used to calculate the dose in the build-up region from both square and rectangu...

Background: This study was conducted to evaluate the recurrence patterns of GBM in regard to its contact with LVs, the relation between radiation doses to subventrivular zone (SVZ). Materials and Methods: Between 2012 and 2014, 80 adult patients with GBM were included this trial. Median follow-up period was 15 months. Median tumor size was 4.5 cm (1.3-8 cm), where 58% of the patients had a tumo...