External Beam Radiation Therapy (EBRT) refers to the delivery of direct radiation beams from outside to inside the body at cancer tissues inside the body. A course of EBRT involves several daily treatments over a few days to a few weeks depending on the disease and stage. It is a cancer treatment option that uses radiation to shrink the tumors. EBRT can be delivered in various forms.
Three-dimensional conformal radiotherapy (3DCRT) goal is to deliver a conformal dose distribution to tumors, while sparing surrounding normal structures. The 3DCRT generally uses increased number of radiation beams to improve dose to the tumors. Very beneficial for tumors close to vital organs and structures.
Intensity-modulated radiation therapy (IMRT) is an advanced mode of high precision radiotherapy in which non uniform fluence is delivered. It manipulates photon beams of radiation to conform to the shape of a tumors using collimator leaves. The intensity of each beam is controlled and it changes shape during treatment. This modality limits side effects
Image guided radiation therapy (IGRT) is the process of using imaging to improve the precision and accuracy of treatment delivery. IGRT is used to treat tumors in area that moves. The linear accelerator itself is equipped with imaging technology that helps image the tumors before and even during treatment. It accurately pinpoints where radiation should target.
Rapid arc is an extremely fast and precise form of image guided IMRT. Delivers complete treatment with one or two rotations. Whole treatment takes less than two minutes.Creates better dose distribution with reduction of time.
Stereotactic radio surgery (SRS) is a non surgical radiation therapy used to treat small tumors of brain. Few high dose treatments are delivered compared to normal conventional treatment. Helps to preserve healthy tissue. When SRS is used to treat body tumors it is called SBRT (Stereotactic body radiotherapy). These are outpatient procedures.