Electron Multileaf Collimator: a price winning development for RT with electron beams
In photon Radiation Therapy Multi Leaf Collimators are standard equipment for modern Linacs. The leaves are close to the beam source and need to be of high density material and thin in order to get good beam shaping properties in ISO centre. MLC are a basic requirement for IMRT.
In electron therapy still applicators are used to shape the beam, which needs to be done close to the patient.
The EMLC was designed as a substitute for all electron applicators, and as it made similar to photon-MLC design, remote controlled beam collimation and isocentric dose delivery can be done, similar to photon RT.
EMLC is a device enabling Linacs for IMRT of Electron beams!
EMLC is mounted to the Gantry by means of an adapter, and the 30 leaf pairs made of brass shaper the field up to the field size of 21.4 cm x 21.4 cm in 100 cm ISO center distance. The leaf pairs are located 16 cm above the ISO center.
In comparison to the standard applicators there are some difference in penumbra and surface dose, which can be compensated.
The total weight of the EMLC is 23 kg, a special cart helps to do the mounting to the gantry fast and safe.
Adapters for all types of Linacs are available.
EMLC was developed in cooperation between Euromechanics Medical GmbH and University Medical Center Hamburg-Eppendorf and is 'Made in Germany'. The German Society of Medical Physics' awarded the "Elekta Research Prize", and both the "German Society of Radiation Oncology" and "European Society for Therapeutic Radiology and Oncology" for its purpose to enable IMRT applications and electron radiotherapy.
EMLC - Milestone in electron beam therapy:
- No Block Absorber
- Optimal Therapy of superficial cancers
- IMRT with electrons feasible
- Close to the patient
The EMLC consists of 30 brass leaf pairs with bottom edge located 16 cm above the isocenter. The resulting maximum field size at 100 cm isocenter is 21.4 cm x 21.4 cm. All leaves can be moved up to a fourth of the maximum field size beyond the central field axis (leaf overtravel).
In comparison with the standard applicator from 6 to 14 MeV, the only differences in dose distribution are the greater beam penumbra of 0.7 to 0.3 cm and the larger build-up effect in the depth-dose curves quantified by the lower surface dose of 3 to 4%. Radiation leakage of the EMLC at 14 MeV amounts to 1.5 to 2.5% relative dose, which could be effectively reduced up to the dose contribution from photon contamination of the electron beam due to our tongue-and-groove leaf design. The total weight of the EMLC is 23 kg.
Compact and user-optimized control unit
- Dual independent position measuring system for increased safety
- System design enables an independent function of the real controller
- Flexible user interface individually adaptable to the user’s needs
- Space saving single unit directly attached to the EMLC
- Thin cable loom with connectors provides ease of installation and operation