1. A method for detecting and diagnosing Parkinson's disease in a human, comprising: administering a derivative compound of glycerophosphocholine (GPC) to a human subject, wherein the derivative compound of GPC is capable of being imaged by the medical imaging process; imaging a brain of the human subject with the medical imaging process; measuring a signal intensity from the brain of the human from the medical imaging process, wherein the signal intensity includes an output from a binding of plural molecules of the derivative compound of GPC to α-synuclein within the human brain to detect and diagnosis Parkinson's disease.