First you must complete a 4-year bachelor's degree and be accepted into medical school. After 4 years of med school, you are required to complete a 5-year residency, which provides specialized training in diagnostics and various types of imaging. It adds up to 13 years of schooling.
Radiology is a very specialized field that requires 15 years of study after high school. This includes: 4 years of college, 4 years of medical school, 5 years of medical residency, and 2 years in a specialization program.
In order to become a radiologist you must complete the proper training and schooling. Depending on if you want to just take the x-rays or read them the schooling will vary from becoming a doctor to a two year degree.