Introduction: One of the concerns about using of high energy photons in radiotherapy is neutron contamination production. The threshold energy of photoneutron production in most materials with high atomic number is about 7MeV. Therefore, it seems to be logical that the main components with high atomic number elements used in the LINAC head have a large contribution to the neutr...

introduction:  stereotactic  radiosurgery  is  a  technique  for  the  treatment  of  intracranial  lesions  with  highly  collimated  x-ray  beam.  linac-based  radiosurgery  is  currently  performed  by  two  techniques:  couch or pedestal mounted. in the first technique, a device is required to affix patient's head to a couch  and  moreover  to  translate  it  accurately.  structure  of...

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 optim...

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...

For the medical linear accelerators (linac) that utilize more than 10 MV of photon energy, components inside linac head become radioactivate during 10–15-year operating cycle. Prior to disposal, radioactive waste must be evaluated for activity, and same procedure should followed linacs. In Republic Korea, regulation methodology radioactivity evaluation is not established yet. this study, we emp...

Introduction: Monte Carlo calculation method is considered to be the most accurate method for dose calculation in radiotherapy. The purpose of this research is comparison between 6 MV Primus LINAC simulation output with commissioning data using EGSnrc and build a Monte Carlo geometry of 6 MV Primus LINAC as realistically as possible. The BEAMnrc and DOSXYZnrc (EGSnrc package) M...

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...

Background: The lack of lateral electronic disequilibrium (LED) becomes a main problem in small field. This factor affects the dose in target volume cannot predict correctly. In addition, utilization of high-energy linear accelerator (10 MV) can emit some unwanted particles (electron contamination). Therefore, the aim of this study was to characterize head linear accelerator (linac) Varian Clin...

BACKGROUND Stereotactic radiosurgery uses a single fraction high dose radiation while stereotactic radiotherapy uses multifractionated lower dose focused radiation. MATERIALS AND METHODS Radiosurgery used rigid CRW head frame while stereotactic radiotherapy utilized GTC or HNL relocatable frames. Stereotactic planning and radiation involved Radionics X-plan and LINAC system. RESULTS Since D...

Different types the spectrum of photons were studied; they were emitted from the flattening filter of a LINAC Varian 2100 C/D that operates at 15 MV. The simplified geometry of the LINAC head was calculated using the MCNPX code based on the studies of the materials of the flattening filter, namely, SST, W, Pb, Fe, Ta, Al, and Cu. These materials were replaced in the flattening filter to calcula...