Medical doctors should have M.D. listed after their names, but not Dr. before their names.
WRONG: Dr. Richard L. Shapiro of New York University says.
RIGHT: Richard L. Shapiro, M.D., of New York University says.
On first reference, give the specialty and location after the name.
Richard L. Shapiro, M.D., a surgeon at New York University Langone Medical Center in New York.