Background: Megavoltage beams used in radiotherapy are contaminated with secondary electrons. Different parts of linac head and air above patient act as a source of this contamination. This contamination can increase damage to skin and subcutaneous tissue during radiotherapy. Monte Carlo simulation is an accurate method for dose calculation in medical dosimetry and has an important role in opt...

BACKGROUND In modern radiotherapy, it is crucial to monitor the performance of all linac components including gantry, collimation system and electronic portal imaging device (EPID) during arc deliveries. In this study, a simple EPID-based measurement method has been introduced in conjunction with an algorithm to investigate the stability of these systems during arc treatments with the aim of en...

In Korea, when replacing or discarding parts of a medical linear accelerator (linac), self-disposal is required in the consideration activity, but there no standard regulation to manage radioactive waste. The aim this study check activity each part determine disposal time according clearance level for self-disposal. results measuring components linac head disposed Varian, Elekta, and Siemens eq...

PURPOSE A key factor limiting the effectiveness of radiation therapy is normal tissue toxicity, and recent preclinical data have shown that ultra-high dose rate irradiation (>50 Gy/s, "FLASH") potentially mitigates this effect. However, research in this field has been strongly limited by the availability of FLASH irradiators suitable for small animal experiments. We present a simple methodologi...

PURPOSE Using magnetic resonance imaging (MRI) for real-time guidance during radiotherapy is an active area of research and development. One aspect of the problem is the influence of the MRI scanner, modeled here as an external magnetic field, on the medical linear accelerator (linac) components. The present work characterizes the behavior of two medical linac electron guns with external magnet...

Radiation therapy treatment planning for many clinical situations requires wedgeshaped isodose distributions. The wedged dose distributions can be generated through the use of physical wedges (PWs), motorized wedges and the synchronization of jaw or multileaf collimator dynamic motion with accelerator dose output. Modern medical accelerators are usually equipped with a dynamic wedge (DW) option...

A novel platform for LINAC-based SRS treatment, the Edge, (Varian Medical Systems, Palo Alto, CA) offers multiple imaging modalities for treatment localization, including an optical surface monitoring system (OSMS) for surface tracking, 2.5 MV portal imaging, triggered monoscopic kV imaging to track intra-fractional motion, 4D CBCT to evaluate tumor motion offline, extended CBCT images by stitc...

Background/Aim. In the past two decades, we have witnessed emergence of new radiation therapy techniques, radiotherapy treatment planning system (TPS) with calculating algorithms for dosage calculation in a patient, units multislice computed tomography (CT) and image-guided delivery. The aim study was investigating significant difference dosimetric TPS relation to values obtained by measuring o...

Individual QA for IMRT/VMAT plans is required by protocols. Sometimes plans cannot pass the institute's QA criteria. For the Eclipse treatment planning system (TPS) with rounded leaf-end multileaf collimator (MLC), one practical way to improve the agreement of planned and delivered doses is to tune the value of dosimetric leaf gap (DLG) in the TPS from the measured DLG. We propose that this ste...