Dosimetry for the study of medical radiation workers with a focus on the mean absorbed dose to the lung, brain and other organs

Abstract

Background

The reconstruction of lifetime radiation doses for medical workers presents special challenges not commonly encountered for the other worker cohorts comprising the Million Worker Study.

Methods

The selection of approximately 175,000 medical radiation workers relies on using estimates of lifetime and annual personal monitoring results collected since 1977. Approaches have been created to adjust the monitoring results so that mean organ absorbed doses can be estimated.

Results

Changes in medical technology and practices have altered the radiation exposure environments to which a worker may have been exposed during their career. Other temporal factors include shifts in regulatory requirements that influenced the conduct of radiation monitoring and the changes in the measured dose quantities.

Conclusions

The use of leaded aprons during exposure to lower energy X rays encountered in fluoroscopically based radiology adds complexity to account for the shielding of the organs located in the torso when dosimeters were worn over leaded aprons. Estimating doses to unshielded tissues such as the brain and lens of the eye become less challenging when dosimeters are worn at the collar above the apron. The absence of leaded aprons in the higher energy photon settings lead to a more straightforward process of relating dosimeter results to mean organ doses.

Keywords:

• Dosimetry
• epidemiology
• personal monitoring

Disclosure statement

The author’s report no conflicts of interest. RCY was employed by Landauer Inc. who provided the database being used by the NCRP for the Million Person Study. CNP is currently employed by Landauer, Inc. The work in preparing this paper is entirely voluntary, entails no financial implications and only involves the scientific interpretation and application of the radiation measurement data acquired many years ago by Landauer.

Additional information

Funding

This work was supported in part by grants from the National Aeronautics and Space Administration [Grants No. NNX15AU88G and 80NSCC17M0016], a grant from the Centers for Disease Control and Prevention [5EU1EH000989] and a grant from the U.S. Department of Energy [Grant No. DE-SC0008944 awarded to the National Council on Radiation Protection and Measurements, which included interagency support from the U.S. Nuclear Regulatory Commission, the U.S. Environmental Protection Agency and the National Aeronautics and Space Administration].

Notes on contributors

Robert C. Yoder

R. Craig Yoder directed the technical activities and programs at Landauer, Inc. from 1983 through his retirement in 2015. In this capacity he influenced the technologies and measurement protocols used by the Company as it delivered dosimetry services around the world. He currently is using his historical knowledge to advise the MPS epidemiologists regarding the methods to translate personal monitoring information into mean absorbed doses to various organs. He is a Council member of the National Council on Radiation Protection.

Lawrence T. Dauer

Lawrence Dauer is Associate Attending Physicist specializing in radiation protection at Memorial Sloan Kettering Cancer Center in the Departments of Medical Physics and Radiology. He is a Council and Board member of the NCRP and served as a member of the ICRP Committee 3, Protection in Medicine.

Stephen Balter

Stephen Balter is a Professor of Clinical Radiology (physics) at Columbia University. He is an international authority on all aspects of medical fluoroscopy. He is a member of Council of the National Council on Radiation Protection and Measurements, and served as the char of NCRP Report-168 – Radiation Dose Management for Fluoroscopically-Guided Interventional Medical Procedures.

John D. Boice

John Boice is President of the National Council on Radiation Protection and Measurements and Professor of Medicine at Vanderbilt University. He is an international authority on radiation effects and served on the Main Commission of the International Commission on Radiological Protection and on the United Nations Scientific Committee on the Effects of Atomic Radiation. He directs the Million Person Study of Low-Dose Health Effects.