VARIAN TrueBeam accelerator at DOSEO
The VARIAN TrueBeam accelerator, installed on the DOSEO platform, is a medical linear accelerator that can deliver photon and electron beams for calibration services and the development of new dosimetric references adapted to the technical evolutions of radiotherapy.
This accelerator allows the delivery of radiotherapy beams in all new photon and electron modes. It is equipped with a multi-blade collimator of 120 blades and onboard 3D imaging systems kilovolt (kV-CBCT) and megavolt (MV). It can deliver photon beams of 6, 10, 15 and 20 MV with flow rates from 0.05 Gy/min to 6 Gy/min. It also allows the delivery of 6 and 10 MV high-flow FFF beams (“Flattening filter free” or without equalizer cone) with flow rates up to 14 and 24 Gy/min respectively. Electron beams of 6, 9, 12 and 18 MeV are available with flow rates from 1 to 10 Gy/min. The accelerator is equipped with an interchangeable radio transparent carbon table with an aluminium profile table to fix and position various phantoms or instruments. A robot is fixed to the ceiling of the casemate and allows the detectors to move along the 3 axes in the beam, around the isocentre.
Our job: metrology
Implemented methods for the establishment of national references must be adapted to the radiation type and its intensity. They are based on measurement technics such as calorimetry, ionometry and chemical dosimetry.
The variety of the emitted radiation and physical forms of the sources oblige to adapt the measurement process in order to establish national references: methods with defined geometries, or 4 p countings geometries, coincidence countings, etc.