Can rabbis become doctors

If one has the fortitude and the financial resources to sustain the necessary years of study, a rabbi can become a doctor, and a doctor can become a rabbi ... the only difference being which course of study one decides to complete first. There are many individuals in the US and around the world who hold both Rabbinical ordination and Doctorate in medicine or some other field. The choice of which field to pursue as one's primary source of income is also entirely up to that individual ... or he can practice both, if he can find a way to fit them in.