Answer to Question #2536 Submitted to "Ask the Experts"

Category: Doses and Dose Calculations — External dose calculations

The following question was answered by an expert in the appropriate field:

We use TLD (thermoluminescent dosimetry) in our personnel monitoring service. We have a two-element card. I want to know how we can estimate the effective dose from the two readings.

Your question addresses an area that has been evaluated in research for some years. Thermoluminescent dosimetry (TLD) results are generally expressed to give the dose to the skin and the lens of the eye and the deep dose equivalent. Extrapolating the results beyond this requires a detailed knowledge of the photon spectrum and the geometry of the radiation field with respect to the wearer of the TLD. Of course, the TLD has an angular response itself that also must be considered. ANSI N13.11 (available to Health Physics Society members at this Web site) gives the information on TLD calibration requirements for the various categories under NVLAP (the National Voluntary Laboratory Accrediation Program) for whole-body dosimeters. Also, you may refer to NCRP Report 122, "Use of Personal Monitors to Estimate Effective Dose Equivalent to Workers for External Exposure to Low-LET Radiation."

Philip C. Fulmer, CHP, PhD

Answer posted on 21 April 2003. The information and material posted on this Web site is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of materials and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Web site. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.