Sealed Source Users

Sealed source training is recommended for persons who handle sealed and plated radioactive sources.    Sealed and plated sources consist of radioactive material that is either encased in metal or plastic (sealed sources) or radioactive material that has been plated as a thin film onto metal or plastic (plated sources).  Because the radioactivity is encapsulated or plated onto a surface, under normal conditions sealed and plated sources do not present a significant contamination hazard but they may present a significant external exposure hazard, depending on the properties of the radionuclide or the amount of activity present. While most sealed sources are stand-alone sources used to calibrate or check instrumentation, to irradiate materials, or for experiments in laboratories, sometimes analytical equipment such as gas chromatographs and liquid scintillation counters contain sealed sources.

Persons who use Gamma Irradiators may need specific training that goes beyond this module to fulfill training requirements to use these devices.  This training also does not fulfill training requirements for persons who use open sources of radioactivity, which is the form used in most biomedical research. Contact the Radiation Safety Office (RSO) at 206.543.0463 for information about other radiation safety training available.


This page describes the radiation safety training program for people who handle sealed sources at the University of Washington.  The sealed source training has two components.  Click on the buttons for additional information about these training elements.

  1.  Computer-based training modules covering Sealed Source Radiation Basics topics

  2.  A test on the topics included in the Sealed Source Radiation Basics modules


There are seven computer-based training modules:

  • Radiation Properties
  • Background Radiation & Other Sources of Exposure
  • Biological Effects
  • Government Regulations and the Radiation Safety Program
  • External Dose Limits
  • Radiation Dosimetry
  • Working Safely with Sealed Sources

These modules provide information on the following topics:

  • the basic characteristics of  radiation, including the properties of various radioactive emissions
  • half-life
  • radiation units
  • natural background and other sources of radiation exposure
  • the biological effects of radiation exposure
  • the risks of radiation exposure
  • rules and regulations
  • the administration of the radiation safety program at the University of Washington
  • annual radiation dose limits
  • the ALARA Philosophy
  • when radiation dosimetry is required and when it is not
  • the Declared Pregnant Worker Program
  • The properties of the sealed sources used at the University of Washington
  • Guidelines and requirements for handling sealed sources


You may take this test if you have completed the Sealed Source Radiation Basics Modules.  If you have attended radiation safety training at any other institution, you must read through the Regulations Module, the Dose Limits Module, the Dosimetry Modules and the Working Safely with Sealed Sources Module before you take the test.

Completion of this test does not certify you to use any other radioactive materials except sealed sources.  If you plan to use open sources of radioactive material, you must complete the radiation safety training program for open source users
Radiation Safety Training.


If you have never attended radiation safety training at any institution or would like to review all of the training modules:
Go to the beginning of the Sealed Source Radiation Basics Modules

If you have taken radiation safety training at another institution, you must read about the rules, regulations and the administration of the University of Washington's radiation safety program, the dosimetry program at the University of Washington, and the guidelines and requirements for handling sealed sources:
Begin at the Government Regulations portion of the Modules

If you would like to go to a specific module:

If you are ready to take the test:

Go to the Sealed Source Radiation Basics Test