Radiation Safety


Dosimetry and Bioassay
Radiation exposures can arise either from radioactive materials that spontaneously emit ionizing radiation or from devices that produce x-rays or other forms of radiation such as electrons or protons. Regulatory agencies require personnel radiation exposures to be maintained as low as is reasonably achievable (ALARA). Determining whether an individual receives a measurable radiation dose requires an effective personnel monitoring program; therefore, the measurement and documentation of personnel radiation doses are essential services offered by RSS. The RSS Dosimetry Program provides state-of-the-art radiation monitoring dosimeters and maintains permanent records of all personnel radiation doses. Dosimeters are currently exchanged at monthly or quarterly intervals. Refer to the Forms link to obtain necessary dosimetry forms. If you have questions regarding radiation monitoring dosimeters, please call 764-4294.

RSS also provides various radio-bioassay services to measure and record the intake of radioactive material resulting from inhalation or ingestion. Internal dosimetry techniques evaluate radioactive material intakes by locating the radionuclide in the body (in vivo) or by analyzing bodily fluids such as urine (in vitro).

Additional Information


All users of radioactive material or radiation-producing devices must be trained in the safe use of such material and devices. Please refer to list below for appropriate training.

Radioactive Material Users:
Radiation Safety Orientation Course

X-Ray Diffraction Users:
In-house training by a RSS Health Physicist

Radiographic or Fluoroscopy X-Ray Users (UMHHC Employees):
In-house training by a RSS Health Physicist

Radiographic or Fluoroscopy X-Ray Users (Campus Employees):
In-house training by a RSS Health Physicist

Declared Pregnant Woman (DPW) Program
Effective January 1, 1994, the Nuclear Regulatory Commission (NRC) implemented a revised set of federal regulations (10 CFR 20) limiting the dose to an embryo/fetus during an entire pregnancy, due to occupational exposure of a declared pregnant woman to 500 mrem.

Declared Pregnant Woman: a female employee who has voluntarily informed her employer, in writing, of her pregnancy and the estimated date of conception for the purpose of evaluating fetal radiation dose during the term of pregnancy to ensure the fetal dose is kept below the regulatory limit (500 mrem).

The Declaration of Pregnancy Form provides the formal means by which a pregnant occupational radiation worker voluntarily notifies RSS of her choice to authorize the application of federal and/or state radiation dose limits to an embryo/fetus (500 mrem / gestation period) as a condition of her radiation-related work at the University of Michigan. A Declaration of Pregnancy to Radiation Safety Service can only be made by use of this form.

The total dose to the embryo/fetus is the sum of the deep dose equivalent (external recorded dose) and the dose from any intakes of radioactive material by the declared pregnant woman [10 CFR 20.1208 (c)].

The 500 millirem dose limit applies only to occupational exposure, not from any dose (medical x-rays, Nuclear Medicine diagnostic tests or therapy treatments) the woman may receive as a patient.

If a woman chooses 'not' to declare her pregnancy to the U-M (ie: Radiation Safety Service), then she has the right to do so and her annual dose limit would remain that of a regular 'radiation worker' (5,000 mrem).

The choice of whether to declare one’s pregnancy is a personal one and is to be an informed one. A pregnant occupational radiation worker needs to be cognizant of information supplied by the NRC, and RSS as to the potential health effects from radiation to herself and to an embryo/fetus. RSS supplies written instructional material discussing such potential effects and will assist the pregnant worker in understanding the material contained therein to allow her to make an informed choice.

The pregnancy dosimeter badge is issued monthly and should be worn in addition to the participant’s regular badges around the naval area (waist).

The instructional material includes the following documents:

  • Declaration of Pregnancy Form:
    A pregnant occupational radiation worker can voluntarily declare her pregnancy by completing this form and submitting it Radiation Safety Service.
  • Pregnancy Declaration Expiration Form:
    A declaration of pregnancy automatically expires when the associated condition of pregnancy actually ceased or upon termination of employment as an occupational radiation worker with the University of Michigan. A declared pregnant worker should provide RSS with a signed and dated written notice of the expiration of pregnancy. This can be done by completing and submitting a Pregnancy Declaration Expiration Form.
  • Pregnancy Declaration Revocation Form:
    A declared pregnant worker may voluntarily revoke her declaration of pregnancy at any time for any reason. This can be done whether or not the pregnancy has concluded.
  • NRC Regulatory Guide 8.13 – Instruction Concerning Prenatal Radiation Exposure
  • NRC Regulatory Guide 8.29 – Instruction Concerning Risks From Occupational Radiation Exposure
  • Reproductive Health Awareness Guideline