by DrDave » Wed Mar 03, 2004 11:35 pm
All types of doctors first go to medical school (or osteopathic school) and then choose a residency in the field they want to practice. For example, a pediatrician would go through medical school and then do a residency in pediatrics.
There are some doctors, called "sub-specialists" who have to do a fellowship after residency for extra training. For example, to become a cardiologist, you'd first go to medical school, then do a residency in internal medicine (3 years), then do a fellowship in cardiology (3-4 years last I checked). Some people even further subspecialize, so if you wanted to be a cardiologist who specializes in echocardiograms, you would do a fellowship in echocardiography after your cardiology fellowship.
Hope that helps.