Long-term Neurovascular Complications After Radiation Therapy in Head and Neck Cancer

This study tracks long-term brain and blood vessel (neurovascular) complications that can develop in head and neck cancer survivors after receiving radiation therapy. Researchers use brain imaging and blood vessel scans to detect problems like stroke risk, blood vessel narrowing, or cognitive decline. **You may be eligible if...** - You are 20 or older with a history of head and neck cancer - You received radiation therapy within the past 72 months (prospective group), or more than 10 years ago (retrospective group) - You have had at least one brain image and blood vessel study done since completing radiation **You may NOT be eligible if...** - You are under 20 years old - You are unwilling to sign informed consent Talk to your doctor to see if this trial is right for you.