Dosimetry

Any individual who is occupationally exposed to ionizing radiation and is likely to receive a dose in excess of 10 percent of the applicable annual allowable limit will be issued a radiation monitoring device (radiation dosimeter). The radiation dosimeter is worn by the individual to monitor and track external radiation exposures. Individuals working with volatile or large quantities of unsealed radioactive material are required to undergo in vivo or in vitro bioassay measurements to assess the intake of radioactive material and determine the corresponding radiation dose. Thyroid probes are performed on workers handling I-131 and I-125 as sodium iodide, and urine bioassays are performed on workers handling high activities of beta emitters. In addition, bioassays are performed as part of the response to spills or accidental releases.

Reports of the personnel exposures and bioassay measurements are reviewed monthly by the Radiation Safety Office (RSO) to look for unusual or unexpected levels. In accordance with the as low as reasonably achievable (ALARA) philosophy, any exposures greater than 10 percent of the maximum permissible dose are investigated and reported to the University Radiation Safety Committee.

Copies of the dosimetry reports may be sent to departments and posted for individuals to view their exposures for each monitoring period. Individual radiation exposure or bioassay measurement results may be requested at any time from the RSO.