Please note that it is the policy of Children's National Hospital to ensure a "drug-free" work environment: a workplace free from the illegal use, possession or distribution of controlled substances (as defined in the Controlled Substances Act), or the misuse of legal substances, by all staff (management, employees and contractors). Services provided at the main hospital include general radiography, fluoroscopy, special procedures (interventional), nuclear medicine, positron emission tomography, ultrasound, computerized axial tomography, bone densitometry, and magnetic resonance imaging.