1. As Low As Reasonably Achievable (ALARA) – The guiding principle for the radiation safety program. Radiation exposure will be minimized to the point practical for both workers and the general public.
2. Committed Effective Dose Equivalent (CEDE) – “the sum of the products of the committed dose equivalents for each of the body organs or tissues that are irradiated multiplied by the weighting factors (W_T) applicable to each of those organs or tissues (H_E,50 = ΣW_TH_T.50)” [10 CFR 20.1003].
3. Control Dosimeter – A dosimeter kept in an area of the workplace representative of background radiation for the facility. This dosimeter is used to differentiate background dose from exposure for personal dosimeters.
4. Declared Pregnant Worker – A participant who has voluntarily chosen to disclose their pregnancy and provides the necessary information to the RSS for the issuance of a fetal dosimeter. 
5. Deep Dose Equivalent (DDE) – ”the external whole-body exposure dose equivalent at a tissue depth of 1 cm (1000 mg/cm²)” [10 CFR 20.1003]. 
6. Dose – a generic term that will refer to “effective dose equivalent” (EDE) unless otherwise specified. 
7. Dosimetry Coordinator (DC) – a worker in each department who receives and distributes dosimeters to participants and fulfills other delegated dosimetry duties as outlined below. 
8. Dosimetry Participant (Participant) – a radiation worker who has their radiation dose monitored as part of the overall dosimetry program. 
9. Dosimetry Provider – an individual or organization that provides, processes, and evaluates individual dose monitoring equipment to determine the radiation dose delivered to the equipment. 
10. Effective Dose Equivalent (EDE) – “the sum of the products of the dose equivalent to the organ or tissue (H_T) and the tissue weighting factors (W_T) applicable to each of the body organs or tissues that are irradiated (H_E = ΣW_TH_T)” [10 CFR 20.1003].
11. High Radiation Area – “an area, accessible to individuals, in which radiation levels from radiation sources external to the body could result in an individual receiving a dose equivalent in excess of 0.1 rem (1 mSv) in 1 hour at 30 centimeters from the radiation source or 30 centimeters from any surface that the radiation penetrates” [10 CFR 20.1003].

12. Lens Dose Equivalent (LDE) – “the external exposure dose equivalent to the lens of the eye at a tissue depth of 0.3 centimeters (300 mg/cm²)” [10 CFR 20.1003].

13. Minor – An individual less than 18 years of age.

14. Monitoring Period/Frequency – the duration that a given participant’s dosimeter should be worn. Typically, this will be one quarter or one month. 

15. Radiation Area – “an area, accessible to individuals, in which radiation levels could result in an individual receiving a dose equivalent in excess of 0.005 rem (0.05 mSv) in 1 hour at 30 centimeters from the radiation source or from any surface that the radiation penetrates” [10 CFR 20.1003].

16. Radiation Safety Staff (RSS) – radiation safety professionals, working as part of the University of Missouri’s Environmental Health & Safety (EHS) Department, responsible for safety and compliance of all radioactive material and radiation-generating equipment on campus and at university healthcare facilities.

17. RAM – radioactive material.

18. Shallow Dose Equivalent (SDE) – “the dose equivalent at a tissue depth of 0.007 centimeter (7 mg/cm²), which applies to the external exposure of the skin of the whole body or the skin of an extremity” [10 CFR 20.1003].

19. Subaccount – a group of participants as defined by the dosimetry provider; they have the same DC and generally receive the same dosimeter(s) per participant. They have the same radiation risk as evaluated by the RSS.

20. Total Effective Dose Equivalent (TEDE) – “the sum of the effective dose equivalent (for external exposures) and the committed effective dose equivalent (for internal exposures)” [10 CFR 20.1003].

     

1. General dosimetry requirements

   1. Dosimeters shall be issued to participants who are likely to receive, in one year from external sources to the body, a dose greater than 10% of the limits found in 10 CFR 20.1201(a) and shown in Figure 1. [10 CFR 20.1502(a)(1)]. 

   2. Participants may not exceed an annual TEDE of 5 rem (0.05 Sv) OR an annual LDE of 15 rem (0.15 Sv) OR a SDE of 50 rem (0.5 Sv) to the skin of the whole body or to the skin of any extremity, as shown in Figure 1.

      

   3. Dosimetry Coordinators shall notify the RSS if a minor needs to become a participant. Minors are not eligible to become participants without prior approval by the RSS. Annual doses to minors from external sources shall remain less than 100 mrem DDE, 150 mrem LDE, or 500 mrem SDE [10 CFR 20.1502(a)(2)]. 
   4. Declared Pregnant Workers may not exceed 500 mrem to the embryo/fetus during the entire pregnancy and shall wear dosimeters if they are likely to receive 100 mrem DDE during their entire pregnancy [10 CFR 20.1208(a), 10 CFR 20.1502(a)(3)]. 
      1. Fetal dosimetry will only be assigned to RWs who are currently issued dosimetry. Declared Pregnant Workers without already issued dosimetry are not considered to have a fetal dose that would require monitoring.
   5. Participants entering a high radiation area must wear dosimetry [10 CFR 20.1502(a)(4)].
      1. All entrances into a high radiation area must first be approved by the RSS.
      2. Any person entering a high radiation area must additionally have real time monitoring through an electronic personal dosimeter.
   6. Per MU’s License Tie-Down Requirements, persons handling greater than or equal to 1 millicurie of gamma or high-energy beta emitters shall wear extremity monitors unless dose estimates performed by EHS RSS can verify likely doses are below 10% of any applicable limit in 10 CFR 20.
   7. The RSS will perform a dosimetry evaluation to determine if RWs need dosimetry based on anticipated RAM or X-Ray uses. A dosimetry evaluation must be performed prior to actual first use of any new radiation source. Evaluations need not be made for every individual; evaluations can be made for employees with similar job functions or work areas.
   8. Anyone assigned a dosimeter must receive radiation safety training, regardless of the radiation source, as outlined in the Radiation Safety Manual.
   9. Control dosimeters are sent along with assigned dosimeters. These dosimeters should be stored in a background dose area (i.e. not an area with active RAM use) and returned with the assigned dosimeters.
2. Dosimetry Provider Responsibilities

   1. Personnel monitoring devices such as film badges, optically stimulated luminescence (OSL) dosimeters, or thermoluminescent dosimeters (TLDs) must be evaluated by a provider that is National Voluntary Laboratory Accreditation Program-approved, as required by [10 CFR 20.1501(d)].
   2. The dosimetry provider must process returned dosimeters in a reasonable timeframe to allow prompt communication of dose data with participants and oversight bodies. 
   3. Participant dose information must be made available to the RSS as needed for NRC reporting requirements.
   4. The dosimetry provider must comply with other RSS requests as needed for regulatory compliance.
3. RSS Responsibilities

   1. The RSS are responsible for maintaining overall radiation safety, including monitoring the recorded doses of all dosimetry participants. 
   2. Prior to any new use of radiation, whether RAM or x-ray generating machines, the RSS will perform a dosimetry evaluation to determine if personnel monitoring is needed. 
      1. Dosimetry evaluations should be performed by the RSS during the initial RAM permit application and during each renewal period of a RAM permit.
      2. When determining the need for personnel dosimetry, RSS will evaluate factors such as: 
         1. Radiation sources (radionuclides, device inventory, etc.)
         2. Room layout and wall/floor materials
         3. Participant orientation and distance to radiation source
         4. Estimated activity used per procedure and the frequency of procedures performed annually
         5. Standard operating procedures
      3. The results of this evaluation will be recorded in the Health Physicist Review document for the relevant RAM or X-ray use permit and/or special conditions of the permit.
      4. The Dosimetry Coordinator or Permitted Individual (PI) is responsible for notifying the RSS if changes in radiation uses occur. If changes are substantial, the RSS will perform a new dosimetry evaluation.
   3. If the need for dosimetry is determined, the RSS will assist with setting up a new subaccount or working with the Dosimetry Coordinator to have dosimeters ordered for a new RW.
      1. Dosimetry Subaccounts should be divided based on departments and/or employees with similar exposures that can be reasonably managed by a single Dosimetry Coordinator.
   4. The Radiation Safety Officer (RSO) will review all dose reports as they are received, and generate quarterly ALARA reports as part of the ALARA Program described in MU’s License Tie-Down Requirements and NUREG-1556 Volume 7.
   5. The RSS will maintain an online database of participant dose history. Paper and digital dose reports will also be available upon request. Annual dose reports (NRC Form 5) and cumulative dose reports (NRC Form 4) are accessible via the EHS Assistant website [10 CFR 19.13].
   6. If an individual’s dose exceeds 100 mrem TEDE or 100 mrem to any individual organ or tissue, the RSS will provide an annual dose report to that individual [10 CFR 19.13(b)(1)].
   7. The RSS will provide previous employer dose history reports upon request. These requests will be furnished within 30 days after the exposure of the individual or 30 days from the time of the request, whichever is longer [10 CFR 19.13(c)(2)].
   8. The RSS will oversee the application process for new dosimetry participants.
      1. New participants can apply for dosimetry monitoring online through the EHS Assistant website.
      2. Applications will be reviewed and approved by both the appropriate Dosimetry Coordinator and the RSS.
   9. The RSS is responsible for ordering new dosimeters from the dosimetry provider once the dosimetry application has been approved. 
   10. Participant removals and edits can be accomplished by emailing the RSS at rad@missouri.edu. 
4. Participant Responsibilities

   1. All dosimetry program participants must receive basic dosimetry training, with additional training requirements dependent on job function.
   2. Participants are responsible for wearing their dosimeters correctly and returning them via their Dosimetry Coordinator.
      1. Dosimeters should remain in the participant's workspace but not near radiation sources. Dosimeters should not be taken home.

      2. Participants must wear the dosimeter for the entire duration of activities involving radiation exposure in the correct orientation and position as assigned by the RSS.

         1. All whole-body dosimeters should have the plastic tab labeled ‘remove’ taken off before use.
         2. All dosimeters must have the labeled face with the participant’s name pointing towards the radiation source.
         3. When possible, chest dosimeters should be worn outside of a labcoat or other applicable garment. If wearing the dosimeter on the outside of the labcoat could potentially damage the dosimeter due to the work being performed, it should be worn on an inner layer of clothing with the label still facing outwards.
         4. Chest dosimeters should be worn towards the midpoint of the abdomen as shown in Figure 2. They can be worn on either side of the body and attached to a pocket or lapel.
         5. Collar dosimeters should be worn along the collarbone as shown in Figure 2.

         6. All collar dosimeters should be worn outside of lead protective garments unless otherwise specified by the RSS. Wearing a collar badge under lead will result in inaccurate EDE and LDE dose estimates due to the correction factor normally applied for RWs who wear lead.

            1. NOTE: fetal dosimeters should be worn underneath lead. Fetal dosimetry does not have the same lead correction factor applied.
            2. NOTE: chest dosimeters are not typically assigned for RWs who work around radiation sources that require lead protection. If a RW is assigned a chest dosimeter and needs to wear lead for a procedure, it should be worn underneath the lead.

             

            

         7. Ring dosimeters should be worn on the hand that will be handling RAM or in an X-Ray field and can be worn on any finger.
            1. The ring dosimeter label should be facing towards the source of radiation as shown in Figure 3. For handling RAM, the label should be facing towards the palm. For performing procedures in an x-ray field, such as fluoroscopy, the label should be facing away from the palm. 
            2. Ring dosimeters should be worn underneath gloves as shown in Figure 3.

          

         

   3. If an RW has multiple dosimeters due to work in multiple departments or external workplaces, they should not be used interchangeably. An RW should only use and store dosimeters at their specific workplace or department. 
      1. MURR is not a part of the MU Campus Materials License. All RWs who work at MURR and at MU (campus, MU Healthcare, CRMC, or the Veterinary Hospital) are considered as working under two different licenses. The RSS will work with the RW and MURR to ensure that dose limits are not exceeded under either license.
      2. RWs who work at CRMC and the associated Jefferson City clinics, are under the MU Materials License. They are not considered as being monitored under two licenses. 
         1. If the RW is working at multiple clinics, they will be assigned a dosimeter for each clinic.
      3. RWs who are working at MU and another location outside of MURR will be considered as being monitored under two or more licenses. The RSS will work with the RW and the other licensee(s) to ensure that dose limits are not exceeded for the RW.
   4. If an RW is assigned dosimetry from the University and plans to receive a diagnostic or therapeutic treatment with RAM (radiopharmaceuticals), then the RW must inform the RSS prior to the treatment. The RSS will advise the RW on how to continue to monitor occupational exposure without interference from the medical treatment or scan.
   5. Participants will not automatically receive a copy of their dose history unless they receive >100 mrem annually [10 CFR 19.13(b)(1)].
      1. Dose history can be obtained by the participant through the EHS Assistant website, or a copy of their dose history can be requested directly through the RSS. 
   6. Individuals who no longer work at the University of Missouri and desire a copy of their dose records must contact the RSS for a termination report.
   7. RWs who are pregnant have the option of declaring their pregnancy.
      1. If a pregnant RW chooses to declare their pregnancy to the RSS, then the Declared Pregnant Worker (DPW) will have their exposure limits reduced during the gestational period. The RSS will also monitor exposure monthly.
      2. Only RWs should declare a pregnancy. Non-RWs do not need to declare pregnancy.
      3. If a pregnancy is declared, the DPW will be assigned a fetal dosimeter with limits of 50 mrem/month and 500 mrem for the entire gestation period from the point of declaration [10 CFR 20.1208], [NCRP No. 174].
      4. If a pregnancy is not declared, the RSS will not enforce additional dose restrictions or assign a fetal dosimeter.
      5. If discretion is desired, DPWs can choose to work directly with the RSS rather than the Dosimetry Coordinator to declare pregnancy and order fetal dosimeters.
      6. The RSS is available for consultation regarding DPW status. Further information regarding prenatal radiation exposure can be found in NRC Regulatory Guide 8.13.

      7. To wear a fetal dosimeter, place the dosimeter at abdominal height as shown in Figure 4. If shielding such as lead aprons are worn, place the fetal dosimeter under the shielding.

          

         

      8. Fetal dosimeters are monthly dosimeters and should be exchanged on a monthly basis even if the DPW’s regular assigned dosimetry is on a quarterly basis. Dose reports will be reviewed by the RSO once received from the dosimetry provider. The DPW will not be automatically updated with fetal dosimetry reports and will only be notified if fetal dose limits are exceeded.
         1. The DPW has the right to request fetal dosimetry records at any point if they so choose.
5. Dosimetry Coordinator (DC) Responsibilities

   1. The Dosimetry Coordinator is the main point of contact for the dosimetry program in their department or subaccount. The Dosimetry Coordinator will maintain a working knowledge of all RWs in their area to build and maintain a current roster of dosimetry program participants. This will be accomplished by: 

      1. Assisting new participants in completing training, submitting dosimetry applications, and approving their applications for review by the RSS.

      2. Informing the RSS of any participants that need to be removed from the subaccount or have their dosimeter information otherwise altered. 

      3. Informing the RSS of any change in departmental or billing contact information.

   2. Dosimetry Coordinators will be provided training materials and working guides through the EHS department website with specific instructions for adding new participants and maintaining compliance with the broader radiation safety program. 

   3. The Dosimetry Coordinator is responsible for receiving mail from the RSS and distributing dosimeters to participants in their subaccount.

   4. The Dosimetry Coordinator is responsible for collecting used dosimeters and returning them to the RSS via campus mail or other means when the monitoring period is concluded. 

      1. For ease of use and completeness, the RSS recommends the use of badge boards, mail slots, or any other organizational aid to assist in collecting all dosimeters.

      2. Dosimeters will be batched and shipped by the RSS to the Dosimetry provider for evaluation.

   5. The Dosimetry Coordinator acknowledges that dosimetry equipment fees must be paid through departmental invoicing to the RSS which may include late and lost fees for missing dosimeters. Return schedule, and late and lost fees will be listed on the EHS website.

   6. Loss or damage to dosimetry equipment during a monitoring period will be reported to the RSS for replacement with spare dosimeters if possible. 

   7. A DC may request an updated dosimetry evaluation based on significant changes to the use of radiation in their subaccount such as new equipment, materials, or procedures. 

   8. Participant and subaccount dose records may be requested from the RSS as needed. 

   9. Dosimetry Coordinators can view dose records for their subaccount from the EHS Assistant website.

   10. Dosimetry Coordinators are not responsible for maintaining a dose history for their participants. However, Dosimetry Coordinators may be asked to assist the RSS in estimating missing dose information or participating in over-dose investigations. 

   11. Dosimetry Coordinators are not responsible for dose history requests from outside organizations, and such requests may be forwarded to the RSS for follow-up. 

        

References

1. K. J. Schiager, M. McDougall, R. Christman, E. Party, J. Ring, D. Carlson, C. Warfield, and W. Barkley, “Consensus Radiation Protection Practices for Academic Research Institutions”, Health Physics, vol. 71, no. 6, pp. 960-965, Dec. 1996. 

2. 10 CFR 19. U.S. Nuclear Regulatory Commission, “Notices, Instructions and Reports to Workers: Inspection and Investigations”, U.S. Code of Federal Regulations. Accessed: https://www.ecfr.gov/current/title-10/chapter-I/part-19

3. 10 CFR 20. U.S. Nuclear Regulatory Commission, “Standards for Protection Against Radiation”, U.S. Code of Federal Regulations. Accessed: https://www.ecfr.gov/current/title-10/chapter-I/part-20

4. National Council on Radiation Protection and Measurements, “Preconception and Prenatal Radiation Exposure: Health Effects and Protective Guidance”, Rep. no. 174, May 2013, pp.180.

5. U.S. Nuclear Regulatory Commission, “Consolidated Guidance About Materials Licenses; Program-Specific Guidance About Medical Use Licenses”,  NUREG-1556, vol. 9, rev. 3, 2019. Accessed: https://www.nrc.gov/docs/ML1925/ML19256C219.pdf

6. U.S. Nuclear Regulatory Commission, “Instruction Concerning Prenatal Radiation Exposure”, Regulatory Guide 8.13, rev. 3, 1999. Accessed: https://www.nrc.gov/docs/ML0037/ML003739505.pdf

7. U.S. Nuclear Regulatory Commission Materials License 24-00513-32, Tie-down Requirements, Sept. 2023.

8. Radiation Safety Manual, University of Missouri Environmental Health & Safety, Columbia, MO, June 2024. Accessed: https://ehs.missouri.edu/program-areas/radiation-safety/radiation-safety-manual

    

Revisions

1. Rev 00 – 2023-10-24 – New SOP.  

2. Rev 01 – 2026-06-17 – Revision.