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

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individual dose limits

Federal and State Authorities establish legal dose limits that an employee should not exceed in a calendar year. Administratively, ISU establishes more conservative values than allowed by Federal and State authorities and the ALARA goals (explained in the next section) are set and self imposed by the ISU Radiation Safety Committee in order to minimize personnel exposure.

"NRC" occupational dose limits

The annual adult (persons 18 years of age or older) occupational dose
limit established by the United States Nuclear Regulatory Commission is the more limiting of:
  • The total effective dose equivalent being equal to 5,000 mrem (5 rem); or
  • The sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue other than the lens of the eye being equal to 50,000 mrem (50 rem).
  • An eye dose equivalent of 15,000 mrem (15 rem), and
  • A shallow dose equivalent of 50,000 mrem to the skin or to each of the extremities (50 rem).

"Idaho State University's" Administrative Occupational Dose Limits (legal limits set by ISU)

The annual adult occupational dose limit is the more limited of:

  • The total effective dose equivalent being equal to 2,000 mrem (2 rem); or
  • The sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue, being equal to 10,000 mrem (10 rem)
ISU's administrative occupational dose limits are far less than the occupational dose limits set by the NRC or the State of Idaho.

"Idaho"Quarterly Occupational Dose Limits (applies to X-ray and accelerator users only)
  • Whole body; head and trunk; active blood-forming organs; lens of eye or gonads                             1,250 mrem/calendar quarter.
  • Hands and forearms; feet and ankles 18,750 mrem/calendar quarter.
  • Skin of whole body 7,500 mrem/calendar quarter.


General Public Dose Limits

The dose limit for members of the general public, including all persons who are not classified as radiation users, is a total effective dose equivalent not to exceed 100 mrem per yearThe State limit is actually 500 mrem per year, however, we use 100 mrem to be consistent with the Nuclear Regulatory Commission (NRC).


Fetal Dose

The embryo-fetus may be more susceptible to radiation effects than an adult and is, therefore, subject to a lower dose limit.  The dose limit for the embryo-fetus is 500 mrem (5 mSv) during the entire gestation period.  As a further precaution, this limit should not be experienced in an acute fashion, but rather distributed relatively uniformly during the gestation period if it is to be experienced (Regulatory Guide 8.13). This degree of protection for the embryo-fetus can only be achieved with the cooperation of the employee. It is recommended that she notifies her supervisor or the RSO as soon as the pregnancy is known. In order for a pregnant worker to take advantage of the lower exposure limit and dose monitoring provisions, the woman may declare her pregnancy in writing to the TSO. A sample letter for declaring a pregnancy is available on the TSO web page or by clicking here. This notification is optional, and at the discretion of the employee the TSO encourages the act of notification, when appropriate. Unless a woman declares her pregnancy, ISU can not set special dose equivalent limits for her. A sample letter for declaring a pregnancy is available on the TSO web page.

Dose Limits for Minors

The dose limits for minors (persons under 18 years of age) are 10% of the adult occupational dose limits.

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This web based training was developed for use within Idaho State University.  It is intended for use by, and applies to ISU employees, staff, visitors, and students.  If this web site or any part of it is used elsewhere, neither its authors nor the University accept responsibility for its contents.  This information may NOT be used for commercial development or profit.