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Improved Tc-99 Analysis in Air Filters for Cancer Diagnosis

Learn about a new approach to Tc-99 analysis in air filters that eliminates high bias, simplifies procedures, and reduces false positives, aiding in the diagnosis of cancer. The innovative TEVA resin method enhances accuracy and efficiency, with significant improvements over traditional TBP methods. Discover how the new air filter procedure streamlines the process and enhances results, meeting required detection limits. Acknowledging the contributions of key professionals, this method offers faster processing times and eliminates mixed waste, contributing to a more effective methodology.

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Improved Tc-99 Analysis in Air Filters for Cancer Diagnosis

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  1. Tc-99 Analysis in Air Filters, An Approach to Eliminate High Bias Mitch Abbate Barringer Laboratories Golden, Colorado

  2. Technetium • Discovered in 1937 by Segrè and Perrier • First Element Produced Artificially • Fission by-product • 213,000 Year Half-life, Beta Emitter • Very Soluble • Can Cause and Help Diagnose Cancer

  3. Barringer Analysis of Tc-99 • Historically, Tc-99 extracted into TBP • Messy/ Difficult to meet TAT and MDL • Mixed Radioactive/ Organic Waste • Evaluation of Eichrom’s TEVA Resin • Simpler Procedure • No Mixed Waste • Concern over False Positives with Air Filters

  4. Eichrom TEVA Procedure • Oxidize Tc to TcO4-, Tc(VII) • Pass sample through TEVA Resin (pH=2) • Rinse Resin with 0.01 N HNO3 • Transfer Resin to LSC Vial • Add Cocktail • Count via LSC

  5. False Positives • Air Filter Samples • Pb-210 Possible Culprit • Pb-210 in U-238 Decay Chain • Beta Emitter/ Interference with Tc-99

  6. Pb-210? • Spiked Samples with 500 pCi Pb-210 • Up to 30% Activity Found on TEVA Resin via LSC • Tried ppt. Pb w/ FeOH • Slight Activity Reduction • Recounted Original Samples • Significant Activity Drop • Bi-210 Half-Life 5.01 days

  7. Bi-210 • Ca(PO4)2 ppt. • Good Results but Too Time Consuming • Bi uptake in HF on Strong Base Resin • No Adsorption • Ref. J.P. Feris, Anal. Chem., 32, 520 (1960)

  8. Re (VII) Uptake

  9. HF Evaluation • HF Added to Load Solution • Precipitation • Rinse with HF • Bi Removed to Near Background • Some Tc-99 Yield Reduction • Rinse with HF/Nitric Acid • Near 100% Tc-99 Recoveries: no Bi or Pb • TSIE’s best with 5 N HF although 1 N OK

  10. New Air Filter Method • Tc-99 Leach w/ 1 N Nitric • H2O2 + Heat to Insure TcO4- • Dilute to < 0.3 N Nitric Acid • Load on TEVA Resin (100-150µ) • 25 mL Rinse w/ 0.01 N Nitric • 20 mL Rinse w/ 5 N HF-0.01 N Nitric • 25 mL Rinse w/ 25 mL 0.01 N Nitric • Direct Addition of Resin to LSC Cocktail • After Dark Adaptation: LSC Counting

  11. TEVA RESIN

  12. Barringer Vacuum Box

  13. Summary • Method Used for All Sample Types • Tc-99 yields average >91% • Batch of 18 Samples (+ 6 QC) • 6 Hours Total Processing Time • Two Times Faster than TBP Method • Meeting Required Detection Limits • Eliminate Mixed Waste • Eliminate Reruns

  14. Acknowledgement • Jim Preston, Barringer Laboratories • Anil Thakkar and Larry Jassin, Eichrom • Phil Horwitz and Andy Bond, PGRF

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