For the most part, state-of-the-art linear accelerators do provide effective and safe care for cancer patients, and Americans safely receive an increasing amount of medical radiation each year. Radiation helps to diagnose and treat all sorts of cancers, saving many patients' lives in the process, and is administered safely to over half of all cancer patients. Whereas older machines were only capable of imaging a tumor in two dimensions and projecting straight beams of radiation, newer linear accelerators are capable of modeling cancerous tumors in three dimensions and shaping beams of radiation to conform to those shapes.