How Radiation Therapy Works

The most common type of radiation therapy is external beam radiation therapy, also known as teletherapy. Teletherapy is delivered by a radiation-producing machine like a linear accelerator. The patient is precisely positioned on a table, also called a couch, near the machine. Positional devices such as a Vac-Lok™ cushion or a thermoplastic mask are often used to ensure accurate positioning of the patient. Radiation travels from the machine to the patient, where the radiation dose is delivered to the tumor, impacting normal tissues as little as possible. While the patient remains in position, the machine rotates around the patient so that radiation is delivered from many different angles.

Each treatment takes just a few minutes and does not cause any discomfort. The treatments are performed while the patient is under general anesthesia, to prevent movement of the patient and therefore, changes in the treatment field. Our veterinary anesthesiologists and technicians monitor the patients very carefully during the procedure to ensure appropriate depth of anesthesia is maintained.


