Electron MLC

The EMLC – a prizewinning development

Electron MLC

The EMLC opens up a new vista for the application of IMRT with electrons. “Better adjustment of the dose distribution on near-surface target volumes can be achieved by means of controlled segmentation using different electron energies”, the German Society of Medical Physics (DGMP) states about the development of the eMLC. Also the German Society of Radiation Oncology (DEGRO) and the European Society for Therapeutic Radiology and Oncology (ESTRO) awarded this development for its purpose to enable IMRT applications in electron radiotherapy.

Technical Details

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


eMLC Detail