What is a LINAC?
A LINAC is a Linear Accelerator which is a device that accelerates electrons through a linear tube to high speeds. These electrons then smash into a metal target in which the high speed electrons are stopped. In the process of being stopped they emit high energy x-rays in the direction of their initial motion. The energy of the resultant x-rays is approximately the energy of the electron when they hit the target. The final speed of these electrons is determined by the electrical potential drop across the linear accelerator. The electric potential is on the order of 6,000,000 volts, or "6 Megavolts", or "6 MV". Compare this to the standard electric potential which powers a toaster or refrigerator of 120 volts. Therefore the energy of the x-rays emitted from the LINAC is approximately 6,000,000 volts. Higher x-ray energies mean larger electrical potentials which leads to a longer accelerating cavity. The length of a typical 6 MV LINAC is approximately 6 feet. It is these high energy x-rays which are used to irradiate the patient's tumor.
The acceleration cavity is mounted on a gantry which allows the LINAC to be pointed at s single point in space, however with the freedom to rotate through a full circle. The LINAC can be used to treat lesions anywhere in or on the patient's body.
The Beth Israel Deaconess Medical Center currently has three LINACS in operation on the East Campus.