Cancer accounts for more than a quarter of deaths around the world and in the United States.  The main treatment options for cancer are surgery, systemic therapy (for example, chemotherapy, hormones), and radiation therapy. Sometimes, just one of the treatment types can be used to cure a cancer (for example, internal radiation for certain prostate cancers); other times, multiple treatment types are necessary together (for example surgery and radiation for certain breast cancers).  Radiation therapy plays a key role in our battle against cancer.  There are two principal types of radiation therapy.

(1) External radiation therapy, also called external beam radiation therapy (EBRT), is delivered with a linear accelerator. It includes intensity modulated radiation therapy (IMRT), image guided radiation therapy (IGRT), hypofractionated radiation therapy, stereotactic body radiation therapy (SBRT) / stereotactic ablative radiation therapy (SABR), and stereotactic radiosurgery (SRS).  

(2) Internal radiation therapy, also called brachytherapy (BT), is delivered with an implantable radioactive source.  Brachytherapy includes both high dose rate brachytherapy (HDR-BT) and low dose rate brachytherapy (LDR-BT).