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)
annual adult occupational dose limit is the more limited of:
ISU's administrative occupational
dose limits are far less than the occupational dose limits set by the NRC or
the State of Idaho.
total effective dose equivalent being equal to 2,000 mrem (2 rem); or
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).
"Idaho"Quarterly Occupational Dose
to X-ray and accelerator users only)
body; head and trunk; active blood-forming organs; lens of eye or gonads
1,250 mrem/calendar quarter.
and forearms; feet and ankles 18,750 mrem/calendar quarter.
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 year. The State limit is actually 500 mrem per year, however, we
use 100 mrem to be consistent with the Nuclear Regulatory Commission (NRC).
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
a pregnant worker to take advantage of the lower exposure limit and
monitoring provisions, the woman may declare
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.
The dose limits for minors (persons under 18 years of age)
are 10% of the adult occupational dose limits.