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Radiation Safety Training Module

Study Guide
ISU Technical Safety Office, Campus Box 8106
Pocatello, ID 83209
(208) 282-2311/2310

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Radiation Safety Trng in .doc

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Radiographic Sci Trng in .doc

Radiographic Sci Trng in .pdf


Absorbed Dose
Annual Limit on Intake (ALI)
Bioassay Interval
Committed Dose Equivalent (CDE)
Committed Effective Dose Equivalent (CEDE)
Contamination Survey
Deep Dose Equivalent (DDE)
Dose Equivalent (DE)
Effective Dose Equivalent (EDE)
Eye Dose Equivalent
Radioactive Contamination
Radioactive Half-life
Radioactive Material
Reference Quantity (RQ)
Shallow-dose Equivalent
Tissue Weighing Factors
Total Effective Dose Equivalent (TEDE)

Absorbed Dose: The mean energy per unit mass imparted to any matter by any type of ionizing radiation.

Annual Limit on Intake (ALI): The quantity of a radionuclide which, if taken into the body, produces a committed effective dose equivalent of 5 rem.  Because of differences in physiological transport mechanisms, the ALIs vary depending on the route of intake.  For purposes of contamination control and bioassay procedures, the most conservative ALI, either for ingestion or inhalation, is used.

Bioassay: A bioassay involves directly measuring the radioactive material that may be present in an individual’s body. In some instance, bioassays mean the radioactive materials excreted from the body to infer what is present within human tissue.

Bioassay Interval: The bioassay interval is the maximum time that may elapse between bioassays that will assure detection of the verification level for a given nuclide and assay method.  The bioassay interval for a particular radionuclide is determined by its physical and metabolic characteristics, and by the instrumentation used for the measurement.  For most commonly used radionuclides and typical analytical systems, the bioassay interval is 13 weeks (one calendar quarter); for P-32, and a few other very short-lived radionuclides, however, the bioassay interval is only one month.

Committed Dose Equivalent (CDE): The dose equivalent to organs or a tissues of reference that will be received from an intake of radioactive material by an individual during the 50-year period following the intake.

Committed Effective Dose Equivalent (CEDE): The sum of the products of the weighing factors applicable to each of the body organs or tissues that are irradiated and the committed dose equivalent to these organs or tissues.

Contamination Survey: A systematic investigation to determine the presence, or to verify the absence, of radioactive materials in unwanted locations, e. g. on the body or personal clothing, on surfaces of objects that may be touched or handled, on equipment or materials to be removed from a restricted area, etc.

Deep Dose Equivalent (DDE): The dose equivalent at a tissue depth of 1 cm, resulting from whole body external exposure.

Dose Equivalent (DE): The product of the radiation absorbed dose and the radiation weighing factor, and all other necessary modifying factors at the location of interest.

Effective Dose Equivalent (EDE): The sum of the products of the dose equivalent to the organ or tissue, and the tissue weighing factors applicable to each of the body organs or tissues that are irradiated. 

Exposure: Usually refers to any condition which creates the potential for any individual to receive a radiation dose, either from external irradiation or from internal contamination with radioactive materials.

Extremity: Means hand, elbow, arm below the elbow, foot, knee, and leg below the knee. 

Eye Dose Equivalent: Applies to the external exposure of the lens of the eye and is taken as the dose equivalent at a tissue depth of 0.3 cm (300 mg/cm2).

Penetrating: The dose rate from photons at 1 meter from a point source of 1 millicurie, assumed to be proportional to the inverse of the square of the distance between the point source and the receptor.

Radioactive Contamination: Unwanted presence of radioactive substances on surfaces, air or inside the human body.

Radioactive Half-life: The amount of time that it takes for a radioactive isotope to be reduced by one half of its value through the process of radioactive decay.

Radioactive Material: Any material having a specific activity greater than 70 Bq/g (0.002 mCi/g), in accordance with 49 CFR 173.403. Also, any non-radioactive material (activity less than 70 Bq/g) with surface contamination (both fixed and non-fixed/removable) that, when averaged over each 300 cm2 (46.5 in2) of all surfaces, is equal to or greater than 0.4 Bq/cm2 (10-5 mCi/cm2) for beta and gamma emitters and low-toxicity alpha emitters; and equal to or greater than 0.04 Bq/cm2 (10-6 mCi/cm2) for all other alpha emitters.

Reference Quantity (RQ): A quantity of a radionuclide (expressed in microcuries) related to its relative hazard potential and used to prescribe requirements for handling, monitoring, labeling and disposal.  Reference quantities are obtained from 10CFR20, Appendix C.

Shallow-dose Equivalent: Applies to the external exposure of the skin or an extremity and is taken as the dose equivalent at a tissue depth of 0.007 cm (7mg/cm2) averaged over an area of 1 square centimeter.

Tissue Weighing Factors: The proportion of the risk of stochastic effects resulting from irradiation of that organ or tissue to the total risk of stochastic effects when the whole body is irradiated uniformly. 

Total Effective Dose Equivalent (TEDE): Sum of the deep dose equivalent and committed effective dose equivalent.




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