Duhaime's Law Dictionary

Linear Accelerator Definition:

The primary device used by radiation onologists to deliver and target radiation therapy.

Related Terms: Oncology, Chemotherapy

According to the website of he Radiological Society of North America, Inc., as consulted on August 9, 2004, a A linear accelerator (LINAC) is the device most commonly used for external beam radiation treatments for patients with cancer.

The linear accelerator can be/is used to treat all parts/organs of the body. It delivers high-energy x-rays to the region of the patient's tumor. These x-ray treatments can be designed in such a way that they destroy the cancer cells while sparing the surrounding normal tissue.

"The first clinical use (of a linear accelerator) was n the mid 1970s. The first clinical accelerator began operating at Hammersmith Hospital, London, in 1953. Today more then 4,000 accelerators are in use for radiotherapy around the world."1

linear acceleratorAgain, according to the Radiological Society of North America (RSNA)

"The linear accelerator uses microwave technology (similar to that used for radar) to accelerate electrons in a part of the accelerator called the "wave guide," then allows these electrons to collide with a heavy metal target. As a result of the collisions, high-energy x-rays are produced from the target. These high energy x-rays are shaped as they exit the machine to conform to the shape of the patient's tumor and the customized beam is directed to the patient's tumor. The beam may be shaped either by blocks that are placed in the head of the machine or by a multileaf collimator that is incorporated into the head of the machine. The patient lies on a moveable treatment couch and lasers are used to make sure the patient is in the proper position. The treatment couch can move in many directions including up, down, right, left, in and out. The beam comes out of a part of the accelerator called a gantry, which can be rotated around the patient. Radiation can be delivered to the tumor from any angle by rotating the gantry and moving the treatment couch."


  • NOTE 1: Suhami, Robert, Tannock, Ian, Hohenberger, Peter and Horriot, Jean-Claude, The Oxford Textbok of Oncology, 2nd Ed. (Oxford, Oxford University Press, 2002) at page 398.

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