Impact of the various kVp settings used during computed tomography (CT) simulation that provides data for heterogeneity corrected dose distribution calculations in patients undergoing external beam radiotherapy with either high-energy photon or electron beams have been investigated. The change of the Hounsfield Unit (HU) values due to the influence of kVp settings and geometrical distribution o...

The effect of gantry rotation on beam profiles of photon and electron beams is an important issue in quality assurance for radiotherapy. To address variations in the profiles of photon and electron beams at different gantry angles, a Dynamic Phantom scanner composed of a 20 x 12 x 6 cm3 scanning Lucite block was designed as a cross-beam-profile scanner. To our knowledge, differences between sca...

The aim of this study was to characterize electron contamination a flattened (FF) and an unflattened (FFF) Varian Clinac iX 6X 15X photon beams using Monte Carlo (MC) simulation. EGSnrc MC technique used model the head simulate dose distribution FF FFF beam in water phantom. materials geometrical data linac were provided by Tan Tock Seng Hospital (TTSH) Singapore. modeled removing flattening fi...

Background: One of the main problems of dedicated IORT accelerators is to determine dosimetric characteristics of the electron beams. Monte Carlo simulation of IORT accelerator head and produced beam will be useful to improve the accuracy of beam dosimetry.Materials and Methods: Liac accelerator head was modeled using the BEAMnrcMonte Carlo simulation system. Phase-space files were generated at...

A novel scheme is proposed for generating a polarized positron beam via multiphoton Breit-Wheeler process during the collision of 10 GeV, pC seeding electron with other 1 nC driving beam. The provides strong self-generated field, and suitable transverse deviation distance between two beams enables field experienced by to be unipolar, which crucial realizing polarization. We employ particle simu...

Introduction: In the treatment of breast cancer, breast conserving surgery (BCS) and whole breast irradiation is a usual technique. The influence of lumpectomy boost following breast radiotherapy is apparent, but there are different delivery methods. This work intended to compare the dosimetric parameters of electron beams and photon beams for boosting irradiation in breast can...

background: small photon fields are increasingly used in modern radiotherapy especially in intensity modulated radiation therapy (imrt) and stereotactic radiosurgery (srs) treatments. accurate beam profile and central axis depth doses measurements of such beams are complicated due to the electron disequilibrium. hence the ebt2 (external beam therapy) gafchromic film was used for dosimetry of sm...

Background: Estimating dosimetric parameters for small fields under non-reference conditions leads to significant errors if done based on conventional protocols used for large fields in reference conditions. Hence, further correction factors have been introduced to take into account the influence of spectral quality changes when various detectors are used in non-reference conditions at differen...