Radiology nurses treat patients that are undergoing diagnostic radiation procedures such as radiation therapy, radiography, MRIs, mammography, computed tomography and ultrasound. The major professional organization for radiology nursing is the Association for Radiologic & Imaging Nursing (ARIN). The Radiologic Nursing Certification Board (RNCB), a subsidiary of ARIN, maintains the Certified Radiology Nurse (CRN) credential program. To be eligible to take the CRN credential exam, registered nurses must have an active RN license and at least 2,000 hours of radiology nursing experience within the past 3 years. The U.S. Bureau of Labor Statistics predicts excellent, overall job growth for registered nurses. The median registered nurse salary is $62,450.