background: the monte carlo method is the most accurate method for simulation of radiation therapy equipment. the linear accelerators are currently the most widely used machines in radiation therapy centers. methods: in this work, a monte carlo modelling of the siemens oncor linear accelerator in 6 mv and 18 mv beams was performed. the results of simulation were validated by measurements in wat...

In recent years, the use of gold nanoparticles (GNPs) in radiation therapy has been studied by experimentation and Monte Carlo simulation repeatedly. Although the idea of increasing doses has been raised by high-atomic elements since decades ago, but due to the adaptation of gold nanoparticles with the biological system, scientists have incited more about the various uses of these materials in ...

BACKGROUND The aim of this study was to investigate if the flattening filter free (FFF) irradiation mode of a linear accelerator (linac) is advantageous as compared to the flat beam (FF) irradiation mode in intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) for carcinoma of the hypopharynx / larynx. METHODS Four treatment plans were created for each of 10...

Background: In conventional radiation therapy, regarding normal tissue tolerance, the treatment of bulk tumors is one of the remaining challenges. Grid Radiation Therapy (GRT) is a technique to deliver high doses, approximately 15 – 20 Gy per fraction, to several small volumes located in a large radiation field. This can be performed using a grid block. The current work has concentrate...

The aim of this study was to investigate the radioprotective effect of thymol as a natural product against salivary glands dysfunction induced by ionizing radiation in rats. The rats were treated with thymol at dose of 50 mg/Kg before exposure to radiation at dose 15Gy. Salivary gland function was evaluated with radioisotope scintigraphy and then salivary gland to background counts ratio was ca...

Purpose Prostate motion during radiation therapy (ie, intrafraction motion) can cause unwanted loss of radiation dose to the prostate and increased dose to the surrounding organs at risk. A compact but general statistical description of this motion could be useful for simulation of radiation therapy delivery or margin calculations. We investigated whether prostate motion could be modeled with a...

The present retrospective study was designed to analyze factors with prognostic values a) within, and b) significantly associated with, short-term (12months or less) and long-term (more than 24 months) survival times, i n 72 consecutive patients treated for malignant gliomas. Among 41 (57%) short-term surviving patients, the absence of both aphasia and motor deficit (as initial presenting ...