When the photon beam exits the head of the Linear Accelerator, it passes through the Multileaf Collimator (MLC).  The MLC is composed of 120 computer controlled tungsten leaves that shift to form specific patterns, blocking the radiation beams according to the intensity profile from the treatment plan.

A computerized tool called a Multileaf Collimator (MLC) is located in the head of the Linear Accelerator The MLC is composed of 120 computer controlled tungsten leaves that shift to form specific patterns, blocking the radiation beams; this is performed according to the intensity profile generated from the Treatment Plan.

MLC capability offers patients two unique advantages:

Precision - The system in place at the Welch Cancer Center achieves a very high resolution and therefore maximizes tissue sparing. The MLC is capable of delivering unique doses to very small areas.

Speed - The Multileaf Collimator eliminates the need for the Radiation Therapists to enter and leave the treatment room numerous times to insert and remove previously used lead beam-shaping blocks. The patient is positioned only once per session, rather than multiple times.