PUBLIC AND ENVIRONMENTAL SAFETY
Environmental Health and Safety
RSP-061
External Dosimetry Procedure
1. Overview
a. The external dosimetry program is designed to monitor radiation exposure to areas or
individuals as generated by radiation producing machines or radioactive materials.
Assignment is based upon the likelihood for a workers exposure to approach a fraction of
the regulatory limit and radioactive material quantity threshold levels established by
Radiation Safety staff. Dosimeters are supplied and processed by an accredited outside
vendor. Radiation Safety personnel administers the dosimetry program on all campus
locations as a service.
2. Dosimetry Assignment Criteria
a. Radiation workers likely to receive in excess of 10% of the occupational limits
b.
c.
d.
e.
i. Whole body: 5000 mrem, or
- Individuals working with 1 mCi or more of unsealed materials
where beta emission maximum energy exceeds 1 Mev
- Individuals working with .5 mCi or more of unsealed gamma or
xray emitting materials
ii. eye: 15000 mrem
iii. hands, skin, extremities: 50,000 mrem, or
- Individuals working with 5 mCi or more of unsealed materials
where beta emission maximum energy exceeds 1 Mev
Dosimetry assignment for a declared pregnant worker is made in consultation with the
Radiation Safety Officer.
Any employee requesting dosimetry may be assigned a dosimeter after consultation with
the Radiation Safety Officer and/or Radiation Safety staff.
Departments that require all visitors to wear dosimetry may be provided with an
electronic dosimeter for monitoring radiation dose.
Individuals are assigned to a specific series code for the purpose of segregating exposure
groups and managing the dosimetry program.
3. Dosimeter Wear Period
a. Dosimeters are worn for either a one month period or on a quarterly basis. Wear periods
are determined by Radiation Safety staff for each individual and based upon the potential
to be exposed to radiation and the above established criteria.
i. Quarterly
- Researchers
- Hospital Personnel as determined by Radiation Safety staff
ii. Monthly
- Hospital Personnel as determined by Radiation Safety staff
4. Acquiring Dosimeters
a. Boston Campus - contact Geoffrey C. Sirr at 6-3450 or visit the Tufts EHS website at
http://publicsafety.tufts.edu/ehs/?pid=66. Completed Radiological Worker Registration
forms should be forwarded to Geoff.sirr@tufts.edu .
TUFTS ENVIRONMENTAL HEALTH AND SAFETY
b. Medford and Grafton Campus - contact Chris Rock at 8-4556 or visit the Tufts EHS
website at http://publicsafety.tufts.edu/ehs/?pid=66. Completed Radiological Worker
Registration forms should be forwarded to chris.rock@tufts.edu .
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5. Receipt/Storage of Dosimeters
a. Dosimeters are initially received and stored by Radiation Safety staff. Packages received
by vendors include all assigned, spare, and control dosimeters. After distribution of the
personnel dosimeters, the control dosimeters remain in their package inside the assigned
dosimeter storage area.
6. Distribution and Use of Dosimeters
a. Radiation Safety staff distribute dosimeters to research groups & medical staff or
assigned areas, prior to the beginning of the monitoring period.
b. Radiation exposure to dosimeters should be representative of the assigned work
environment. Dosimeters are not to be worn during medical procedures or at other
licensed facilities where radiation exposures could occur.
c. Return the dosimeter to the badge board, or low background storage area when not in use.
d. Control badges are provided for each series code to accumulate background radiation
exposure and should be co-located with assigned dosimeters when not in use.
7. Collection & Shipment
a. Dosimeters should be gathered by Radiation Safety staff within 5 days after the end of
the monitoring period. To facilitate collection, the supervisor or manager from the
assigned area is contacted the day prior to collection and asked to collect the dosimeters.
This person then transfers badges to or stores the dosimeters for pickup by Radiation
Safety staff.
b. Radiation Safety staff then verifies those collected to the original packing slip provided
by the vendor and subsequently ships the dosimetry package for processing.
8. Care of Dosimeters
a. Personnel are expected to properly handle and care for their dosimeters.
b. Dosimeters should be protected from exposures not representative of occupational
exposure, contamination from radioactive materials, chemical or biological agents, and
physical damage.
c. Locations should be established by supervisors that ensure low background radiation
conditions for temporary storage of assigned personnel dosimeters. Controls should be
co-located at the storage location to ensure occupational exposures are best estimated.
9. Contaminated, lost or damaged dosimeter
a. Dosimeters contaminated, lost or damaged should be immediately reported to Radiation
Safety staff.
b. Replacement dosimetry is available as needed.
c. Dose assignment is conducted by the RSO and based upon assessment by Radiation
Safety staff (i.e. direct interview and often time sensitive assessment) when warranted.
10. Missing or Late dosimeters
a. Those assigned to the dosimetry program are expected to change out dosimeters in a
timely fashion.
b. Immediately contact Radiation Safety staff if it is discovered that your dosimeter is
missing.
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