Historical review of occupational exposures and cancer risks in medical radiation workers

Abstract

Epidemiological studies of medical radiation workers have found excess risks of leukemia, skin and female breast cancer in those employed before 1950 but little consistent evidence of cancer risk increases subsequently. Occupational radiation-related dose-response data and recent and lifetime cancer risk data are limited for radiologists and radiologic technologists and lacking for physicians and technologists performing fluoroscopically guided procedures. Survey data demonstrate that occupational doses to radiologists and radiologic technologists have declined over time. Eighty mostly small studies of cardiologists and fewer studies of other physicians reveal that effective doses to physicians per interventional procedure vary by more than an order of magnitude. For medical radiation workers, there is an urgent need to expand the limited information on average annual, time-trend and organ doses from occupational radiation exposures and to assess lifetime cancer risks of these workers. For physicians and technologists performing interventional procedures, more information about occupational doses should be collected and long-term follow-up studies of cancer and other serious disease risks should be initiated. Such studies will help optimize standardized protocols for radiologic procedures, determine whether current radiation protection measures for medical radiation workers are adequate, provide guidance on cancer screening needs, and yield valuable insights on cancer risks associated with chronic radiation exposure.

Figure 1

Average annual occupational effective radiation dose estimates and time trends in average annual doses in radiologists. National Council on Radiation Protection and Measurements (NCRP) recommendations for whole body doses are shown for comparison with the reported radiation doses. Sources: see detailed dose estimates and references in Table 5.

Figure 2

Average occupational effective radiation doses per procedure and trends in effective doses per procedure to interventional cardiologists for three types of interventional procedures: (a) diagnostic catheterization (DC), (b) percutaneous coronary interventions (PCI), and (c) ablation. Each data point represents the mean value from one published study under similar exposure conditions where the year of publication is used as a surrogate for the year when the procedures were conducted. The size of the data points represents the number of procedures reported. Source: Kim K et al. Health Phys 2008;94:211-227.