Brachytherapy uses radioactive sources called 'seeds' to treat cancer. There are two main types of brachytherapy - intercavitary treatment and interstitial treatment. Intercavitary treatment involves placing the radioactive sources near the tumor such as the vagina, esophagus or lung. Interstitial treatment requires that the radiation is applied directly into the tissue, such as the prostate or breast. High dose rate (HDR) brachytherapy devices robotically insert radioactive sources into the tumor for a short period of time and are later removed. Depending on the area treated, patients may receive several treatments over a number of days or weeks. Often, these procedures are performed on an outpatient basis. Low dose rate (LDR) brachytherapy uses tiny radioactive seeds permanently implanted into tissue such as the prostate. The radiation from these seeds is slowly released over time to treat the cancer. These implants are placed in the operating room, and patients are often able to go home the same day.