title: Radiation exposure from work-related medical X-rays at the Portsmouth Naval Shipyard.
abstract: BACKGROUND
  Previous analyses suggest that worker radiation dose may be significantly increased by routine occupational X-ray examinations. Medical exposures are investigated for 570 civilian workers employed at the Portsmouth Naval Shipyard (PNS) at Kittery, Maine. The research objective was to determine the radiation exposure contribution of work-related chest X-rays (WRX) relative to conventional workplace radiation sources.
  
  
  METHODS
  Methods were developed to estimate absorbed doses to the active (hematopoietic) bone marrow from X-ray examinations and workplace exposures using data extracted from worker dosimetry records (8,468) and health records (2,453). Dose distributions were examined for radiation and non-radiation workers.
  
  
  RESULTS
  Photofluorographic chest examinations resulted in 82% of the dose from medical sources. Radiation workers received 26% of their collective dose from WRX and received 66% more WRX exposure than non-radiation workers.
  
  
  CONCLUSIONS
  WRX can result in a significant fraction of the total dose, especially for radiation workers who were more likely to be subjected to routine medical monitoring. Omission of WRX from the total dose is a likely source of bias that can lead to dose category misclassification and may skew the epidemiologic dose-response assessment for cancers induced by the workplace.
authors.affiliation: Division of Surveillance, Hazard Evaluations, and Field Studies, National Institute for Occupational Safety and Health, Cincinnati, Ohio, USA. RTD2@CDC.gov
authors.forename: Robert D
authors.initials: RD
authors.lastname: Daniels
authors.forename: Travis L
authors.initials: TL
authors.lastname: Kubale
authors.forename: Henry B
authors.initials: HB
authors.lastname: Spitz
mesh_terms: D001853:Bone Marrow / Q000528:radiation effects*; D016022:Case-Control Studies; D006801:Humans; D008281:Maine; D016273:Occupational Exposure / Q000009:adverse effects*; D010779:Photofluorography; D011829:Radiation Dosage; D013902:Radiography, Thoracic; D011874:Radiometry; D012767:Ships; D018709:Statistics, Nonparametric; D014965:X-Rays / Q000009:adverse effects*