Monitoring of Radiation Exposure

EXTERNAL EXPOSURE

At UIC, whole body exposures to external radiation sources are monitored with Luxel badges and TLD rings.  The Luxel badge is sensitive to x rays, gamma rays, and higher energy beta particles.  They will not detect exposure from H-3, C-14, and S-35, which emit low energy beta particles that cannot penetrate the pouch in which the detector is sealed.  Luxel badges are pictured below.
 

Landauer Luxel 
Radiation Monitoring Badge

Extremity (hand or finger) exposures are monitored with TLD rings which contain a small chip of LiF.  The TLD ring badge is capable of monitoring exposure to x rays, gamma rays and beta particles exceeding about  keV.  They are not useful for monitoring H-3, C-14, S-35, Ca-45, etc.
 

Landauer TLD Ring

OBTAINING A LUXEL OR RING BADGE

Luxel badges and TLD rings may be obtained from the Radiation Safety Section, extension 6-7429.  Download and print the application forms or call us at 6-7429 to have forms sent by mail or fax. Most departments have a departmental badge representative who can also provide forms.

BADGE DISTRIBUTION

Radiation monitoring badges should be exchanged on the first working day of the month.  Bring badges and rings to your badge representative promptly.  All badges worn during the prior month should be returned to Radiation Safety by the 10th.  Our office personnel will be glad to help you to identify your badge representative if needed.

MONITORING REPORTS

After collection, badges are sent to Landauer for processing.  Monthly monitoring reports are received by Radiation Safety and are reviewed by a health physicist.  Copies of the reports are sent to the badge representatives and should be posted or provided to the personnel being monitored.  Individuals can also see their monitoring reports at our office, 339 CSN, during normal working hours.

All dosimetry reports are reviewed by a health physicist.  Personnel receiving exposures that exceed 10% of any maximum permissible dose notified in writing about their exposure and the need to review work practices to ensure they are As Low As Reasonable Achievable (ALARA).  Levels exceeding 25% of any maximum permissible dose are investigated by a health physicist.  Overexposures are reported to the individual and to IDNS.  Quarterly ALARA Reports are prepared for review by the UIC Radiation Safety Committee.

INTERNAL EXPOSURE

A small number of personnel who use radioactive material are subject to monitoring for internal radioactive contamination.  Personnel who use millicurie quantities of I-125 to perform iodinations and medical personnel who administer therapeutic quantities of I-131 are required to be monitored by thyroid counting.  Monitoring is performed to verify that radiation safety precautions that are used to prevent exposure to the worker are effective and to calculate the dose to the individual should an uptake occur.  The Radiation Safety Section has a calibrated thyroid monitoring station which is equipped with a 2x2 NaI(Tl) crystal in a shielded collimator.  The individual being monitored places his or her neck in close proximity to the detector.  A health physicist performs the monitoring, which takes only one minute, and prepares a report that is given to the monitored individual.  In our experience, internal contamination is very rare.

The results of radiation contamination surveys for many years indicates monitoring of individuals for internal exposure to other radioactive materials is not warranted.  If an accidental internal contamination is suspected (ingestion, inhalation, absorption through the skin, needle stick, etc.) monitoring using an appropriate bioassay method will be performed by a health physicist.