Mercer University has established its dose limits based on the dose limits recommended by the National Council on Radiation Protection (NCRP) and the Nuclear Regulatory Commission and Agreement States. The following guidelines provide the necessary information for determining the need for personnel monitoring. All dosimeters are provided and processed by a commercial company which meets the certification requirement of the Technology National Voluntary Laboratory Accreditation Program ( NVLAP ).

• If an adult is likely to receive an external radiation dose in excess of 10 % of the total occupational dose limit of 5000 mRem in one year, the institution is obliged to provide a personal dosimeter.

• If a minor, under the age of 18 years old, or a declared pregnant woman, is likely to receive and external radiation dose in excess of 10 % of their occupational dose limit of 500 mRem, the institution is obliged to provide a personal dosimeter.

1. Authorized User (AU)

It is the responsibility of the AU to identify all radiation workers to the RSO. Once the RSO has been notified, it is the duty of the RSO to determine the need for monitoring devices and to provide the radiation worker with the necessary monitoring device(s).

2. Radiation worker

It is the responsibility of all radiation workers to always wear their dosimeter in the research laboratories at the chest or waist level. In addition, if a ring badge has been issued it is required that it be worn when working with radioactive material. All dosimeters shall be stored outside the laboratories in a designated area, or other appropriate location when they are not being worn.

3. Radiation Safety Officer (RSO)

The RSO is responsible for training all radiation workers and providing them with the necessary dosimeters in a timely manner. The RSO must attempt to obtain previous exposure history on any new radiation worker who has been previously monitored elsewhere. In addition, the RSO is responsible for providing the radiation worker with a cumulative annual exposure report.

B. ALARA = As Low As Reasonably Achievable

Mercer University is committed to maintaining exposure levels as low as reasonably as achievable to all personnel within practical and economical limits. This commitment is accomplished in the following manner:

INSTITUTIONAL RADIATION SAFETY COMMITTEE (IRSC) through program review.

RADIATION SAFETY OFFICER (RSO) achieves this through monthly, and annual review of all exposures. In addition, the RSO presents the ALARA Program in all orientation and refresher training with radiation workers.

AUTHORIZED USER (AU) fulfills their commitment by evaluating their procedures, properly training their workers and their commitment to maintaining exposures ALARA in their labs.

RADIATION WORKERS carry through their commitment by properly using personnel monitoring dosimeters, protective clothing and shielding when necessary. Workers achieve the ALARA assurance by performing instrument and wipe surveys in a timely manner, in order to detect unexpected contamination that could lead to additional exposure.

As an integral part of the ALARA program, Mercer University is committed to maintaining all exposure as low as reasonably achievable. In addition, every effort will be made to determine the reason for the exposure, as well as trying to eliminate this occurrence in the future.

The following are dose limits that have been established by the National Council on Radiation Protection (NCRP) and the Nuclear Regulatory Commission and Agreement States

1. Occupation Dose Limits

SITE                                                        LIMIT(mrem/yr)

          Whole Body                                             5000

 Lens of Eye                                             15000

           Extremities/Skin                                     50000

           Pregnant, Fetus                                         500 mrem/term

 

2. Occupational Dose Limits For Minors

* limits are 10 % of the occupational dose limits

    SITE                                                      LIMIT (mrem/yr)

            Whole Body                                             500

            Lens of Eye                                             1500

            Extremities/Skin                                     5000

 

3. Pregnant Workers / Fetal Dose Limits

*Women who declare their pregnancy in writing have the following dose limits:

500 mRem /term; and 50 mRem per month.

4. Non-Occupational Dose Limits / Members Of The Public

100 mRem per year

Note: This figure represents exposure from terrestrial, celestial, and medical sources such as x-rays.

 

 

Bioassays are performed to measure internal exposure doses. Bioassays determine kind, concentration, and location of material in the body. The most common type of bioassay performed measures material that is excreted from the body such as urine. Another common type of bioassay is the thyroid bioassay for detecting the uptake of radioiodine. The need for bioassays is determined during the protocol / project review of the URSO and IRSC. However, other circumstances may require that bioassays are performed; the RSO or URSO can determine this. The following are two common bioassays that are performed.

Tritium Bioassay

Individuals working with 100 mCi or more of an unsealed form of ³H are required to have a bioassay by urinalysis performed with in one week following a single operation and at weekly intervals for continuing operations.

Bioassay by urinalysis must be performed whenever a radiation worker is likely to receive in one year, an intake in excess of 10 % of the Annual Limit on Intake ( ALI ) for ³H which is 8 mCi.

Thyroid Bioassay

Individuals working with volatile or dispersible ¹²⁵I and ¹³¹I are required to participate in the thyroid bioassay program as per the NRC Regulatory Guide 8.20 Applications of Bioassay for ¹²⁵I and ¹³¹I, Revision 1 September 1979. Listed below are a few key points that are applicable to the thyroid bioassay program. This reference is available upon request.

• Any individual handling 1 mCi of unsealed, volatile, radioactive iodine or sufficiently close to the process should participate in the thyroid bioassay program.
• Baseline Thyroid Bioassay: Prior to commencing work with material.
• Routine Thyroid Bioassay: Bioassay should be performed no sooner than 6 hours after the exposure, but within 10 days from the exposure.

 

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