In the United States the Food and Drug Administration (FDA) in collaboration with the Conference of Radiation Control Program Directors (CRCPD) and state and local government agencies surveys clinical facilities about X-ray system air kerma and ancillary data related to patient dosimetry for a variety of diagnostic X-ray examinations. The survey program is known as the Nationwide Evaluation of X-ray Trends (NEXT). The survey utilizes reference patient-equivalent phantoms in the collection of comprehensive technical information. With knowledge of the skin-entrance air kerma, specific tissue doses can be calculated. An overview of NEXT and previously published FDA tissue dose handbooks for diagnostic X-ray examinations is presented.