What is a Linear Accelerator and What Does it Do?

Linear accelerators, LINAC, are used in the treatment of cancer.  High energy x-rays (electrons) are shaped to conform to the size and shape of the patient’s tumor and delivered using a LINAC.   The radiation, simply put, is used to destroy cancerous cells.  They are delivered in the shape of the tumor to hopefully eliminate damage to the healthy tissues surrounding the cancerous tumor.  A LINAC offers several built-in features, depending on the model, that make sure that the prescribed dose of radiation is delivered.

If radiation has been scheduled and will be delivered using a linear accelerator your radiation oncologist will work in conjunction with both a radiation dosimetrist and medical physicist to create a treatment plan that is uniquely designed for you.  Your physician will review your treatment plan with you before it begins and put quality assurance procedures in place to be certain that all parties involved are on the same page and that your treatment will be delivered in the exact same manner.

What is linear accelerator equipment used for?

LINAC, which is short for linear accelerator, is a large-scale piece of medical equipment used in external beam radiation treatment.  Radiation is a treatment option that is given to patients that have been diagnosed with cancer.  Linear accelerators are used to treat a variety of cancers throughout the body.  The LINAC distributes high-energy x-rays (electrons) directly on to the cancerous tumor.  The treatment is deployed in a manner that allows the healthy tissues to receive less of a direct hit than the tumor to help prevent damage.  Several techniques are used when delivering radiation from LINAC systems including:

  • Intensity-Modulated Radiation Therapy (IMRT)
  • Volumetric Modulated Arc Therapy (VMAT)
  • Image Guided Radiation Therapy (IGRT)
  • Stereotactic Radiosurgery (SRS)
  • Stereotactic Body Radio Therapy (SBRT)

How does a LINAC work?

Microwave technology is used in LINAC to speed up electrons within the wave guide (a part inside the linear accelerator).  It then lets the sped-up electrons to strike a dense metal target to produce the high-energy x-ray that is delivered to the cancerous tumor.  Before the radiation (high-energy x-ray beams) are delivered they are shaped into custom beams that match up with the patient’s unique tumor.

Radiation beams are manipulated into the shape of the tumor as they exit the LINAC by a multi-leaf collimator.  The multi-leaf collimator is uniquely designed to each patient and is integrated into the head of the LINAC.  Patients are required to lie completely motionless on a treatment couch.  In order to make sure that the patient is in the correct position laser are used as guides.  The couch that patients are lying on can be manipulated about to make sure the laser beams are in the correct location.  radiation beams are directed out of the LINAC through the gantry.  The gantry revolves around the patient on the couch.  Radiation can literally be delivered from any number of angles simply by rotating the gantry on the LINAC and moving the couch that the patient is lying on.

Who runs the LINAC?

Radiation therapy is prescribed by a patient’s radiation oncologist.  They are the individual in charge of making sure you receive the appropriate dosage of radiation.  Together a medical physicist and dosimetrist decide how the prescribed dose of radiation will be delivered and how long the process will take.  Finally, a radiation therapist will operate the LINAC to give the patient the prescribed dose of radiation treatment.

How is the patient’s safety guaranteed?

The safety of the patient and the radiation therapist are of utmost importance and therefore secured in several ways throughout treatment.   Before treatment is carried out a unique plan is created.  This strategy is evaluated and approved through a few specialists working together including your radiation oncologist, radiation dosimetrist, and medical physicist.  The proposal is double, and triple checked before treatment can be delivered and quality-assurance procedures are done to make sure that the therapy is delivered according to the plan.

LINAC safety is also another important factor in quality assurance.  Linear accelerators have several built-in features that work to ensure a proper dose of radiation is given.  Daily equipment checks are performed on linear accelerators.  Radiation therapists check to ensure radiation intensity is uniform throughout the beam.  Monthly checks are performed by medical physicists monthly and annually on linear accelerators. There are also several internal checks within the LINAC that don’t let the machine run unless all the prescribed treatment requirements are in place.

Radiation therapists continue to observe the patient during treatment using closed-circuit TV monitors.  A microphone is in place within the treatment room to allow patients and therapists to speak during treatment.  Imaging tools are regularly examined to be sure that beam position is the same as it was in the original plan.

The LINAC operator is crucial as well.  Linear accelerator equipment sits within a room that consists of lead and concrete walls.  This prevents radiation beams from exiting the treatment room.  LINAC systems only release radiation when it is turned on so the accidental risk of exposure to radiation is low.

As an independent LINAC service company, Acceletronics is dedicated to delivering the best equipment performance and services for linear accelerators and CT scanners across all major brands and models, as well as new and refurbished LINAC systems for sale.  More information can be found online at https://www.acceletronics.com/.