MedWOW / Articles / Linear Accelerators / Linear Accelerators (LINAC) Today

Linear Accelerators (LINAC) Today

10 March, 2011 | Linear Accelerators

Linear Accelerator

Linear Accelerator

A Linear Accelerator, commonly known as LINAC, has become the standard method of producing photons and electrons for radiation therapy treatments, generating energy for external beam radiation treatments for cancer.  Linear accelerators now account for the majority of treatment machines used today and are complex, computer-powered systems that deliver precise, highly controlled doses of radiation to treat patients. The linear accelerator causes electrons to speed up as they pass through a wave-guide and shoots the particles at a heavy metal target, forming high-energy x-rays. Lines of accelerated x-ray radiation are shaped to target a tumor or surgery site, limiting radiation exposure to healthy tissue while destroying the cancer cells.

For example: a linear accelerator may be used during whole breast radiation, accelerated partial breast radiation, and Intensity-Modulated Radiation Therapy (IMRT). A portable linear accelerator can be brought into the operating room for intraoperative radiation therapy (IORT) during a lumpectomy for breast cancer.

LINAC expertise is most frequently used in multi-session treatments in order to avoid damaging healthy surrounding tissue with too high a dose of radiation. The most important usage of LINAC technology may be its ability to target larger brain and body cancers with a reduced amount of damage to healthy surrounding tissues. The device also has a number of other medical uses. Its radiation can suppress the rejection of an organ transplant, restrain the immune systems of patients undergoing blood and marrow transplantation, and correct certain neurological and cardiovascular disorders.

Linear accelerators produce high-energy electron or photon beams by means of an accelerating structure. Electrons are injected into one end of this structure and are accelerated as they travel towards the other end. If an electron beam is required, these electrons are then passed through several components before exiting the machine. When a photon beam is required, the electrons are directed towards high- density target material. These electrons are stopped in this material and result in the production of photons. These photons pass through several components in the machine to turn them into a therapeutic beam, before exiting the linear accelerator and entering the patient’s targeted area.

LINACs are mounted isocentrically and the system can be divided into four major subsections of linear accelerator parts: the stationary gantry stand/support, treatment table and control console. The major linear accelerator parts are:

  • The electron gun
  • The buncher
  • The LINAC itself

Each part is responsible for a stage in the acceleration of the electrons.