Technically there is one board (the ABR) with 4 exams- Radiation Biology, Radiation Physics (both of which can be take during residency), Clinical Radiation Oncology (can be taken right after graduation) and Clinical Oral Exam (taken ~1 year after passing all written exams). There is a maintenance of certification which required an exam every 10 years; this has been changed to continuous examination (questions on continuous basis). There is also a requirement for continuous education (CME) and self-assessment CME
