A method for producing a solution including a positron emitting zinc cation of 63Zn, and the method comprises bombarding a solution target including 63Cu with high energy protons to produce a solution including a positron emitting zinc cation. A method for detecting or ruling out Alzheimer's disease in a patient comprises administering to a patient a detectable amount of a compound including a positron emitting zinc cation, wherein the zinc cation is targeted to beta-amyloid in the patient, and acquiring an image to detect the presence or absence of beta-amyloid in the patient.