Training emergency responders to use a colorimetric dosimeter
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Training Emergency Responders to Use a Colorimetric Dosimeter. Arthur Desrosiers Sc.D. CHP Dade Moeller & Associates David Lewis Ph.D. International Specialty Products. RADView PD Detector. Visual reading dosimeter Wallet card size 14 month expiration 3-7 days incident use

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Training emergency responders to use a colorimetric dosimeter

Training Emergency Responders to Use a Colorimetric Dosimeter

Arthur Desrosiers Sc.D. CHP

Dade Moeller & Associates

David Lewis Ph.D.

International Specialty Products


Radview pd detector
RADView PD Detector Dosimeter

  • Visual reading dosimeter

    • Wallet card size

    • 14 month expiration

    • 3-7 days incident use

  • Penetrating radiation

    • ~0-500 rem by densitometer or scanner

    • 2-100 rem visual – 95% response within 0.1 s

    • Photons 50 keV – 10 MeV; β >150 keV

  • Dose thresholds set at protective action guides (PAGs) of EPA, DHS, CRCPD, etc.

  • Dade Moeller is design consultant to RADeCO




Gafchromic medical dosimetry films for therapy
GAFCHROMIC Medical DosimeterDosimetry Films for Therapy


Radview pd dosimeter badge
RADView PD Dosimeter Badge Dosimeter

Radiochromic Film

Reference Chart

Protective Action Guidance


Temperature history indicator
Temperature History Indicator Dosimeter

“False Positive” film

hidden under logo

protected from UV

Temperature History Indicator Film

Non-reversible Change to Red at ~60C°

Replace Badge if Red




Quantitative evaluation
Quantitative Evaluation temperature

  • Based on ANSI N13.11 Category I Protocol

    • Irradiating Laboratory: University of Wisconsin Calibration Laboratory, 137Cs

    • Bias + std. dev. : 7.5%


Why human testing and training
Why Human Testing and Training temperature

  • Visual dosimeters must be read by people

    • Goal – 70% correct assessment of PAG

    • Variations in eyesight and interpretation skill

    • Users cannot be calibrated – must adjust visual thresholds to compensate for human variances

    • Validate a training program for users

  • Measure bias and standard deviation of visual readings to calibrate reference chart thresholds

    • Participants read 20 badges with random doses in the range 2-100 rem and estimated dose in blind test

    • Data used to calculate |B| + SD for eye readings

    • ISP lab personnel not associated with project

  • Expand work by Gladys Klemic of DHS


True dose vs eye estimates
True Dose vs. Eye Estimates temperature

A B C D E F G H I J K L M N O P Q R S T



Sd vs bias of visual readout
SD vs. Bias of Visual Readout temperature

VISUAL

LAB


Frequency of bias
Frequency of Bias temperature

-20%

0%


Training and testing firefighters
Training and Testing Firefighters temperature

  • Participants were told that the test supported research into how workers interpret the dose

  • “Testing the dosimeter, not the firefighter”

  • Firefighters scored on Protective Action Guide

    • A correct estimate or a conservative response in next higher category is “correct,” but two categories higher or any lower category is a “failure”

    • Example – badge with 6 rads actual dose read as “LT 5” or “GT 25” rem scored as “failure”

    • Firefighter did not estimate numerical dose, only dose category for PAG determination

    • PAGs are correlated with dose on the badge


Success rates correct pag
Success Rates: Correct PAG temperature

  • ~80% ISP participants

  • ~70% first fire company

  • ~80% for second fire company

* Color shift & texture complicate reading


Adjusting the reference chart
Adjusting the Reference Chart temperature

  • Measurements of the human response curve were used to correct the visual reference chart

  • Account for negative bias of some users

  • Similar to setting a critical limit for lower limit of detection in lab measurements

  • Consistent with “projected dose” criterion of EPA and DHS guidance


Improved training program
Improved Training Program temperature

  • Participants scored a set of three badges with known doses

  • Proctor then displayed true doses for feedback

  • Participants gained proficiency in scoring

  • Small groups of 6-8 with reference control badges


Subsequent testing
Subsequent Testing temperature

  • 20 Dade Moeller office staff volunteers

  • Professional and hourly personnel

  • 21 badges tested in revised version and two variations: “Charley” and “Papa”

  • 420 total readouts

  • Variation “Papa” most accurate

  • Variation “Charley” highest safety





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