Teletherapy, otherwise known as external beam radiotherapy, is a type of radiation therapy used to treat various forms of cancer. This method uses focused beams of X-ray radiation or gamma rays generated by such machines as the linear accelerator, cobalt machine or gamma knife; the beams are aimed at the specific area of the tumor within the body to eliminate the cancer cells. The radiation therapy team working with the patient uses computer software to control the size of the beam in order to accurately bombard the tumor. This helps reduce damage to non-cancerous cells and the organs near the tumor.
Often teletherapy is an outpatient procedure that requires no hospital stay. Treatments can last up to 10 weeks, with most treatment sessions ranging from 10 minutes to half an hour five days per week. These sessions involve application of temporary ink to the body to mark the area of treatment and even small but permanent dot tattoos to help aim the radiation beam. A patient may also need to wear a body mold or a mask to keep the body or head in place during teletherapy treatment.
There are several types of teletherapy. In three-dimensional conformal radiation therapy, the oncologist creates an image of the patient’s insides using imaging technology such as CT scans or MRIs to assess the location of the tumor in relation to the patient’s other body organs. This method allows the oncologist to send a beam just the right size to attack the tumor.
Intensity modulated radiation therapy uses a similar method, but instead of one beam this therapy uses multiple small beams, all of which are aimed differently to create a more accurate radiation therapy. This increased accuracy allows for more powerful radiation to be transmitted while decreasing damage to nearby organs and tissues in the body. These teletherapy methods also may used as a part of another method called image guided radiation therapy, in which the oncologist takes a daily image scan of the body to figure out how to focus the beam as the tumor changes size from the radiation.
Some forms of teletherapy avoid the use of radiation; this is determined by the nature of the tumor and its potential resistance to radiation therapy. Instead of X-rays, oncologists can resort to proton beams or powerful neutron beams to help destroy the tumor. These methods typically are rare, however, and used only to treat specific kinds of cancer.