Do you mean something like this:

@Stateless
public class BlaBlaBean implements BlaBla {
 ....
 public void editMyEntity(Doctor d) {
 // calling entityManager.merge(d) here
 }

 @AroundInvoke
 public Object mySessionBeanInterceptor(InvocationContext ctx) throws Exception {
 Doctor newDoctor = (Doctor) ctx.getParameters()[0];
 Doctor persistedDoctor = entityManager.find(Doctor, newDoctor.getId());

 // comparing the properties values of newDoctor and
 // persistedDoctor manually (or via reflection),
 // save the differences somewhere etc...

 return ctx.proceed();
 }
}