Radiation oncology is also a distinct specialty from diagnostic radiology with a separate residency training program and separate certification exam (administered by the American Board of Radiology). Whereas in radiology, ionizing radiation is administered to diagnose disease and to guide therapeutic interventions, in radiation oncology, ionizing radiation is delivered as a therapeutic intervention itself. While radiation is most commonly used in an attempt to cure or palliate cancer, it can also be used to treat non-malignant conditions. Some of these include trigeminal neuralgia, acoustic neuroma, meningioma, pterygium, pigmented villonodular synovitis, and prevention of keloids. Key concepts/topics in radiation oncology, which are worth reading more about if interested, include fractionation, intensity-modulated radiation therapy, brachytherapy, stereotactic radiation, and organ sensitivity/toxicity.