Stereotactic body radiation therapy (SBRT) involves the delivery of substantially larger doses over fewer fractions than conventional therapy. Therefore, SBRT treatments will strongly benefit patients using vivo patient dose verification, because the impact of the fraction is large. For in vivo measurements, a commercially available quality assurance (QA) system is the COMPASS system (IBA Dosim...

Introduction. In the International Code of Practice for dosimetry TRS-398 published by International Atomic Energy Agency (IAEA), water is recommended as the reference medium for the determination of absorbed dose for high-energy electron beams. Plastic phantoms may be used under certain circumstances for electron beam dosimetry for beam qualities R50 < 4g/cm2 (E0 below 10 MeV). In our study, w...

Electronic portal imaging devices (EPIDs) are potentially valuable tools for linear accelerator quality assurance and for measuring and analyzing geometric variations in radiation treatment delivery. Geometric analysis is more robust if referenced against an absolute position such as the isocenter (collimator axis of rotation), allowing the observer to discriminate between various setup errors ...

A Monte Carlo model of the Novalis Tx linear accelerator equipped with high-definition multileaf collimator (HD-120 HD-MLC) was commissioned using ionization chamber measurements in water. All measurements in water were performed using a liquid filled ionization chamber. Film measurements were made using EDR2 film in solid water. Open rectangular fields defined by the jaws or the HD-MLC were us...

Monte Carlo (MC) algorithms are recognized as the most accurate methodology for patient dose assessment. For intensity-modulated radiation therapy (IMRT) delivered with dynamic multileaf collimators (DMLCs), accurate dose calculation, even with MC, is challenging. Accurate IMRT MC dose calculations require inclusion of the moving MLC in the MC simulation. Due to its complex geometry, full trans...

background: a set of hardware stereotactic radiosurgery is designed and constructed. the scope of this article is to describe how we have designed and developed stereotactic collimation assembly for a 9 mv neptun 10 pc linac. materials and methods: one collimator holder and six collimators were made, with their radiation field diameter between 12.5 mm to 25 mm at isocenter level. beam data, suc...

In volumetric modulated arc therapy (VMAT), treatment is delivered using a continuous arc motion of the gantry with simultaneous variation of mlc position, gantry speed and dose rate. Several manufacturers offer VMAT facilities based on conventional accelerator gantries while others offer tomographic therapy based on ring gantries. A number of centres have begun clinical VMAT treatments in rece...

Stereotactic body radiation therapy (SBRT) using recently introduced multileaf collimators (MLC) is preferred over circular collimators in the treatment of localized prostate cancer. The objective of this study was to assess the clinical usefulness of MLCs in prostate SBRT by comparing the effectiveness of treatment plans using fixed collimators, variable collimators, and MLCs and by ensuring d...

ID: 7461 Title: Multileaf Collimator (MLC) for Field Matching Photon field matching at the beam isocenter using independent jaws is the method of choice in many radiation treatments that require abutted fields. This study evaluated the suitability of using Multileaf Collimator (MLC) for such matching. The study employed a treatment planning system to model the field matching and the modeling wa...