Monitoring Internal and External Exposure

Personnel Monitoring is the measurement of personnel dose through the use of personnel dosimetry, air samples, bioassays, radiation surveys or any combination of the above with related calculations. EHS can monitor the internal and external exposure of RWs by utilizing dosimeters, bioassays, and more. 

Dosimetry may be required for Radiation Workers depending on the isotope, activities, and use types. If you are unsure whether you will need dosimetry, contact your assigned HP or speak with your Authorized User. If you do need to wear dosimetry, fill out the Dosimetry Application found under the Rad Forms link to the right. On this page, you will also find resources and instructions for the following:


How to fill out the Dosimetry Application

  1. Fill out sections 1-9 with your personal information.
  2. Fill in your Dosimetry Series Code. Your AU should know what this code is, but if not, you can either leave it blank or ask your assigned HP.
    • If your AU does not have a Series Code yet, have them contact EHS or the assigned HP to get this set up.
  3. If you do not have a University ID number, contact your assigned HP.
  4. Select the action you wish to take (Add, Delete, Change or Transfer).  Attach a note if applicable.
  5. Circle the dosimeter type(s) you wish to order.  If ordering a fetal dosimeter, you must first contact your assigned HP as additional training may be necessary. You may find additional information on Declaring Pregnancy and Ordering Fetal Badges below.
  6. Check the appropriate Dosimetry History Information box and complete the employer information if required. Note: this section should only be filled out if you have worn a dosimeter within the calendar year. This allows EHS to combine your dose histories into one record. Do not fill this out if you have not worn a dosimeter within the past calendar year.
  7. If you begin working for a separate agency that requires dosimetry monitoring while you are still employed at MU, you must contact EHS.  EHS is required by the NRC to contact the second employer periodically for exposure information.
  8. If you are no longer at MU and your new employer needs your dose history, please contact EHS.
  9. You can either mail or fax the form to: Radiation Safety, 180 General Services Building, and Phone: 882-7018, Fax: 882-7940


How to Wear your Dosimeter(s)

  • Whole body badges should be worn as close to the midline of the body as possible between the waist and neck.
  • X-ray users may be assigned one or two whole body badges.
    • If assigned one whole body badge, it shall be worn outside the protective lead apron.
    • If assigned two whole body badges, one shall be worn under the lead apron and the second one shall be work outside the apron at the collar.  These dosimeters are marked as to the correct location and it is important to be sure they are used correctly.
  • Finger or wrist dosimetry should be worn with the detector medium facing towards the radiation source. 
  • Personnel radiation dosimetry is to be worn only by the worker assigned the dosimetry.
  • It is not the intent of EHS to interfere with any medical treatments or scans that might be medically necessary, but we do need to know if you are to receive a treatment that might impact the accuracy of your dosimeter.
  • Dosimetry issued by EHS is also not to be exposed to other sources of radiation at other facilities without consulting with EHS. This is also true for X-rays i.e. don’t wear your work related dosimeter to a personal radiology scan e.g. doctor’s visit.     
  • Do not store your personal dosimeter close to sources of radiation. For example, if you leave them on your lab coat or desk drawer, make for sure they are reasonably away from sources of ionizing radiation.  In other words don’t store you dosimeter near Radioactive Waste storage containers.
  • Ensure that you are wearing your assigned dosimeter, wearing it correctly as identified on the dosimeter itself, “Chest”, “Collar”, and wearing the correct color and date on dosimeter associated with wear period.  If you questions concerning your dosimetry contact your assigned HP at 882-7018.


General Bioassay Information and Scheduling

A bioassay is the determination of kinds, quantities or concentrations, and, in some cases, the locations of radioactive materials in the human body, whether by direct measurement (in vivo counting) or by analysis and evaluation of materials excreted or removed from the human body.

Generally, bioassays should be performed within seven (7) days after use of specified quantities of tritium (H-3) or within ten (10) days of specified quantities of radioiodines.  The activity level is determined by the way in which the isotopes are used i.e. either in fume hoods or in open bench conditions. 

Some isotopes may be volatile depending on their chemical structure. The Safety Data Sheets (SDS) should be consulted to determine airborne hazards for the specific chemical compounds in question involved in the use of the radioactive material reactions in question.  The SDS available on the EHS website may provide some guidance as to the volatility of the compounds and/or solutions but will not specifically address the radioactive properties.

If you have questions regarding the need for bioassays or to schedule one, contact your assigned HP at 882-7018.  Bioassays are conducted routinely throughout campus and one can usually be scheduled to meet your needs. Describe the isotope, activity and date the material was handled within the time frames mentioned above.


Declaring Pregnancy and Fetal Dosimeters

The following steps should be taken in order to gain the information necessary to make an informed decision regarding the risks of working with radioactive materials during pregnancy: 

  • The individual makes an appointment with a HP or the RSO to discuss the risks of ionizing radiation during pregnancy. See NRC Regulatory Guide 8.13 “Instruction Concerning Prenatal Radiation Exposure” for additional information.  
  • The individual can decide whether or not to declare a pregnancy.  If the individual decides to declare the pregnancy, then she must fill out and sign the "Declaration of Pregnancy" Form provided by EHS under the Rad Forms link to the right.  If she chooses not to declare her pregnancy, she may still request a fetal badge to measure external exposure to the fetus.  However, as a non-declared pregnant woman, her annual dose limit will remain at the 5000 mrem rather than 500 mrem.
  • For help with filling out the Dosimetry Application, see the How to Fill Out the Dosimetry Application section.


How to access Exposure History and the NRC Form 5

The following are instructions on accessing your exposure history and downloading the NRC Form 5 which may be required for a new employer.

  1. Log into the Form 5 EHS Assistant portal
  2. Enter your University Pawprint and associated password, and click the "Sign In" button.
  3. The "Individual Worker History" webpage will open. Select and click the "Dosimetry Exposure" tab at the top of the page next to "Training". This will display all current exposure history data.
  4. To view and download your NRC Form 5
    1. Click on your participant ID number located under the "Participant ID" cell and the line will highlight in red.
    2. Select "Dosimetry Exposure Reports" from the drop-down menu.
    3. Select "NRC Form 5 by Participant," and a pop-up box will appear.
    4. In the pop-up box, enter the calendar year of interest.
    5. Click "View Report"; the report will open in a new window with a pdf NRC Form 5
    6. To print the report, click the printer icon at the top right of the report window.
    7. To exit the report window, click the "x" on the internet menu tab. This will return you to the "Individual Worker History" webpage.
  5. To log out of the "Individual Worker History" web page, click the "Logout" ion at the web page's top right.


Page last updated on August 18, 2022.