Personnel Monitoring Program

There are various ways to measure an individual’s exposure to radiation.  These methods measure internal and external exposure.

The most common methods to measure for external exposure are whole body and ring dosimeters or badges.  In order to detect and evaluate exposure to external radiation, dosimeters are issued to individuals who are likely to exceed 10% of the dose limits set for occupational workers.

The most common methods to measure for internal exposure are thyroid and urine bioassays.

External Exposure

Requirements for Individual Monitoring Devices (Badges)

In order to detect and evaluate exposure to external radiation, individual monitoring devices will be issued to individuals who are likely to receive in one year from sources external to the body a dose in excess of 10 percent of the applicable limits.  The limits are:

 

 

Dose Limit  (rem/year)

Adult Worker

 

 

Total Effective Dose Equivalent

5

 

Total Organ Dose Equivalent

50

 

Lens of Eye

15

 

Extremities/Skin

50

Embryo/Fetus

 

 

Declared Pregnant Worker

Total Effective Dose Equivalent  0.5 rem/9mo

Minor

 

 

< 18 years of age

10% of Adult Limits

    

Categories of Users for which Individual Monitoring Devices (whole body and ring badges) are required:


Radiation Emitter

Minimum Activity Used At Any One Time (mCi)


Example Radionuclides

I-125*

10

I-125

Other gamma emitters(1)
gamma constant > 0.2

1

I-123, Mn-54, In-111, Rb-86

Gamma constant< 0.2

10

K-42, Cr-51, Rb-86, Tc-99m, Cd-109, I-129, Ce-141

Β emitters(2)  Emax > 0.2

10

P-32, Sr-90/Y-90, P-33, Ca-45

Emax< 0.2

Not applicable,
no badge used

H-3, C-14, S-35

Beta-Gamma emitters

Lowest of above applicable activities

I-131, Na-22, Zn-65

(1) G = specific gamma ray dose constant at 1 meter (mrem/hr)/mCi.
(2) Emax = beta particle end point energy, MeV.
* I-125 is listed separately from other gamma emitters because the gamma dose rate constant varies above and below 0.2 (mrem/hr)/mCi depending upon the source of reference.

Pregnant Workers
A pregnant radiation worker may voluntarily declare her pregnancy in writing to Radiation Safety (see Form and Instructions for RS-13, Declaration of Pregnancy).  Radiation Safety will review the RS-13 form and recommend a personnel monitoring program based on the information supplied on the Declaration of Pregnancy form.  Upon declaration of pregnancy the radiation dose to the embryo/fetus during the entire pregnancy will not be allowed to exceed 0.5 rem Total Effective Dose Equivalent (TEDE).         

Minors
If an individual under the age of 18 will be handling radioactive material or will be frequenting laboratories posted for the use of radioactive materials an RS-14 form, Acknowledgment Of Radiation Exposure Limitations For A Minor, must be completed and submitted to Radiation Safety.  Radiation Safety will review the RS-14 form and recommend a personnel monitoring program based on the information supplied in the Acknowledgment Of Radiation Exposure Limitations For A Minor.  The radiation dose to the minor will not be allowed to exceed 500 mrem TEDE per year.

Other Badge Requirements
Some individual monitoring devices are issued due to license conditions apart from the Ohio Administrative Code:

  1. Minors and declared pregnant workers when there is a reasonable possibility for measurable exposure.  This includes working in a room where radioactive materials detectable with a dosimeter are being used:
  2. Individuals operating irradiators or other facilities as may be required by the appropriate license;
  3. Full time employees of the Nuclear Reactor Laboratory and other radiation workers visiting the NRL expected to exceed 10% of their occupational dose limit;
  4. Division of Radiation Medicine personnel handling radioactive materials;
  5. Division of Nuclear Medicine personnel handling radioactive materials;
  6. Regular personnel of the Radiation Safety Section of Environmental Health and Safety expected to exceed 10% of their occupational dose limit;
  7. Patient care coordinators (nurses) and patient care associates involved in the care of temporary brachytherapy implant patients or therapeutic radioiodine patients;
  8. Users of x-ray generating devices or state-registered radioactive material likely to receive a dose in any calendar quarter in excess of 10% of applicable limits;
  9. Individuals entering a high or very high radiation area;
  10. Users operating under requirements from ODH-issued licenses, the University Radiation Safety Officer, and/or the University Radiation Safety Committee.  Factors which may be considered typically include long handling times or lack of experience of handlers.

Obtaining Dosimeters

If an individual is joining a laboratory group already supplied with dosimeters, a copy of a badge requisition (RS-10) can be obtained from this website.  The form must be completed, signed and returned to Radiation Safety.  Upon receipt of the completed requisition and attendance at the OSU Radiation Safety Short Course, a temporary badge can be assigned until the permanent badge has been received.

If an individual or group needs to initiate dosimeter service, contact Radiation Safety for the appropriate forms.  New badge groups, or “series”, will not be started until Radiation Safety has received a completed RS-30: Set Up a New Badge Series form available from the Radiation Safety web site.

Guidelines for Wearing Dosimeters

Store dosimeters where they will not inadvertently be exposed to radiation, excessive heat or moisture.  Badges should only be kept at work, never taken home.

  1. Wear only the dosimeter(s) assigned to you.
  2. Wear the whole body badge on the trunk of your body, at the point where it is most likely to receive maximum exposure.  Be consistent in wearing the badges on the same area of the body.
  3. Wear ring badges under the glove on the hand that will receive the highest exposure, with the dosimeter name label side toward the palm.
  4. If wearing a lead apron, wear the orange collar badge on your collar, outside of the apron.  If you have two dosimeters, then the white whole body badge is worn under the lead apron and the orange collar badge is worn on your collar outside of the apron.
  5. If appropriate, declared pregnant workers will be issued a fetal dosimeter, along with their whole body dosimeter, for the duration of their pregnancy.
  6. Upon receipt of the new dosimeters, immediately turn in the previous dosimeters to your badge coordinator.
  7. If you leave the University, return your badges and holders  to your badge coordinator.  Badge coordinators must inform Radiation Safety to delete the badges of all individuals who have left their badge series and return the badges and holders immediately to Radiation Safety.
  8. Do not wear your dosimeter when you undergo medical exams or therapies which involve radiation exposure.  This includes medical and dental x-rays.
  9. If you suspect that you or your dosimeter may have been overexposed or contaminated, call Radiation Safety immediately.

Records 

Radiation Safety maintains the records of individual monitoring results for all individuals for whom monitoring is required, doses received during planned special exposures, accidents and emergency conditions.  If an evaluation shows that an individual is not likely to exceed 10 % of any applicable limits, there are no record keeping or reporting requirements.

  1. ​Quarterly summary reports for each badge are sent to Radiation Safety and to each series for all individuals issued dosimeters.
  2. ​“Occupational Exposure Record for a Monitoring Period” Forms (NRC Form 5 equivalent) are annual reports of an individual’s occupational radiation exposure.  This record will be maintained by RSS for all individuals who have received > 100 mrem. 

Determination of Prior Occupational Dose

For those individuals for whom monitoring is required, determination of current year exposure at other facilities is required.  To document determination of current year exposure, the individual must provide a Lifetime Occupational History Form signed by the individual or a statement that includes the names of all facilities that provided monitoring for occupational exposure to radiation during the current year and an estimate of the dose received.

In addition, an attempt will be made to obtain the records of lifetime cumulative occupational radiation dose. 

Internal Exposure

Requirements for Bioassays

Urine and thyroid bioassays are required if an individual is expected to exceed 2% of an Annual Limit on Intake (ALI).  An ALI is defined in OAC 3701:1-38-01 (A) (16) as the derived limit for the amount of radioactive materials taken into the body of an adult worker by inhalation or ingestion in a year.  ALI is the smaller value of intake of a given radionuclide in a year by the reference man that would result in a committed effective dose equivalent of 5 rems or a committed dose equivalent of 50 rems to any individual organ or tissue.

Urine Bioassays

  1. All radiation workers in a laboratory are required to submit monthly urine bioassays, if the laboratory uses unsealed or loose form, on a yearly basis, a quantity of radioactive material > 2000 ALI. For laboratories using multiple radionuclides, the need for urine bioassays is determined by whether the sum of the laboratory’s requested yearly activity, for each radionuclide, divided by 2000 ALI > 1.  Urine bioassays are recommended for non-radiation workers in these labs.
  2. A radiation worker is required to submit a urine sample within 72 hours for bioassay, if the individual’s use of an unsealed or loose form at any one time a quantity of radioactive material > 100 ALI.
  3. Urine bioassays will also be submitted in accordance with requirements from the University Radiation Safety Committee.

Thyroid Bioassays

  1. All radioiodine radiation workers in a laboratory are required to have a thyroid bioassay performed if the laboratory uses in unsealed or loose form on a yearly basis a quantity of radioiodine > 2000 ALI.  For laboratories using multiple radionuclides the need for thyroid bioassays is determined by whether the sum of the laboratory’s requested yearly activity for each radionuclide divided by 2000 ALI is greater or equal to 1.  Bioassays must be performed 24 - 72 hours post iodination or post manipulation of  > 1 mCi of radioiodine.  The term “manipulation” as used here includes transfers from stock containers containing >1 mCi.  Thyroid bioassays are recommended for non-radiation workers in these laboratories.
  2. All radiation workers are required to have a thyroid bioassay within 24-72 hours, if the individual uses an unsealed or loose form at any one time a quantity of radioactive material > 100 ALI. 
  3. Thyroid bioassays will also be performed in accordance with requirements from the University Radiation Safety Committee.

Additional Bioassay Requirements 

  1. Radiation Safety personnel, declared pregnant workers and minors are recommended to submit to monthly thyroid and urine bioassays when handling radioiodines and other radioactive materials, respectively.
  2. If a radioiodine therapy patient is critically ill, if there is a medical emergency or exposure to body fluids without protective wear, patient care givers are required to have a bioassay 24 - 72 hours after the period of greatest contact.
  3. Frequency of submission of urine samples and thyroid bioassays as a result of the following circumstances will be determined by Radiation Safety:
    1. The presence of unusually high levels of facial and/or nasal contamination,
    2. Entry into airborne radioactivity areas without appropriate exposure controls,
    3. Operational events with a reasonable likelihood that a worker was exposed to unknown quantities of airborne radioactive materials (e.g. loss of system or container integrity),
    4. Known or suspected incidents of a worker ingesting radioactive material,
    5. Incidents that result in contamination of wounds or other skin absorptions,
    6. Evidence of damage to or failure of a respiratory protective device. 

Single-Use Thresholds for Bioassay Participation

Single-Use Threshold for
TYROID Bioassays
per Radionuclide

Radionuclide

Activity (mCi)

I-123

27

I-124

5

I-125

6

I-131

5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Single-Use Threshold for
URINE Bioassays
per Radionuclide

Radionuclide

Activity (mCi)

C-14

200

Ca-45

80

Co-57

70

Cr-51

2,000

H-3

8,000

In-111

600

Na-22

60

P-32

90

P-33

800

S-35

2,000

Tc-99m

20,000

ALARA Program

Investigational Levels and Overexposures 

Dosimeters

  1. Investigational Level I Notification
    If an individual whole body badge receives 125 mrem deep dose equivalent (DDE) or more, and if a ring badge receives 1250 mrem shallow dose equivalent (SDE) or more, in a quarter, Radiation Safety will notify the individual in writing.
  2. Investigational Level II Notification
    If an individual whole body badge receives 375 mrem DDE or more, or if a ring badge receives 3750 mrem SDE or more, in a quarter, Radiation Safety will notify the individual and his/her supervisor in writing.  The Radiation Safety Section will investigate the exposure and implement reasonable corrective actions to avoid or reduce additional exposure.

Bioassays

  1. Investigational Level I Notification
    If an individual has an intake of >1%, but <10%, of the smallest Annual Limit on Intake (ALI) the University Radiation Safety Officer and the URSC will be informed.
  2. Investigational Level II Notification
    If an individual has an intake of >10% of the smallest Annual Limit on Intake (ALI), the Radiation Safety Section will investigate the exposure and implement reasonable corrective actions to avoid or reduce additional exposure.