http://www.nucleusinc.com/medical-ani... This 3D medical animation describes the process of intensity modulated radiation therapy, or IMRT, including the use of CT scans and the linac machine. Intensity modeled radiation therapy is a procedure used to treat certain forms of cancer, to kill cancer or control cancer growth. Cells in the body grow and divide as part of the normal cell cell cycles, when cells become cancerous however they can continue to grow uncontrollably. Radiation can be used to kill cancer. Intensity modulated radiation therapy can be used to deliver a higher does of radiation to the the cancer cells while sparing the healthy tissue around the cancer cells.