Patients and their organs move; so do tumors. The motion that results simply from breathing can cause a radiation beam to miss its target. Image-guided radiation therapy is one of the most cutting-edge innovations in fighting cancer. Using technology called an on-board imager, your doctor is able to map the tumor's exact location at the time of treatment, and make very fine adjustments to your position to greatly increase the precision of your radiation treatment. Knowing exactly where the tumor is allows clinicians to target only the tumor, sparing the healthy tissue nearby.