CT imaging systems are regulated by the FDA under two statutes. They are regulated as radiation-emitting electronic products under the Radiation Control for Health and Safety Act and as medical devices under the Medical Device Amendments to the Food, Drug, and Cosmetic Act. The regulations implemented under these laws place controls or requirements on the manufacturers of the CT systems rather than on the users of the CT systems.
The use of CT systems for medical purposes is controlled, in the U.S., largely at the State and Local government levels. States control the practice of medicine, license medical practitioners and typically license or register facilities operating medical x-ray systems such as CT systems. Some States have established regulations regarding the operation of screening programs that employ ionizing radiation.
Radiation Safety Standard
Under the Radiation Control for Health and Safety Act, CT imaging systems are subject to the equipment performance standard for diagnostic x-ray systems administered by the FDA. This standard:
- establishes minimum radiation safety requirements for CT systems
- requires that manufacturers produce CT imaging systems that comply with the radiation safety requirements of the performance standard
- requires manufacturers certify that their products meet the standard.
For CT systems, the standard primarily establishes requirements for labeling and for providing product performance information. It does not establish patient radiation dose limits nor does it address the imaging performance or efficacy of CT systems.
Medical Device Controls
Through the Medical Device Amendments, FDA is responsible for assuring the safety and effectiveness of medical devices. Medical devices are classified into one of three classes, based on the risk associated with the device and controls needed to assure safety and effectiveness. CT imaging systems are Class II medical devices. This means they are subject to:
- manufacturer registration and listing
- manufacturer premarket notification to FDA
- good manufacturing practices (quality system) regulations
- general and special controls.
Manufacturers of CT imaging systems must submit premarket notifications (510(k)s) to FDA. In these notifications, they must demonstrate that each new CT system is "substantially equivalent" in terms of its characteristics, performance and safety to CT systems previously cleared or already on the market before the 1976 Medical Device Amendments.