Radionuclide Safety Guideline for Tc-99m

Physical Data

  • Radiation: Gamma 140.51 keV (89.1% abundance)
  • No beta particles emmited.

Half-Life

  • Physical: 6.02 hours
  • Biological: 24 hours
  • Effective: 4.80 hours

Range

  • Dose rates from unshielded 1.0 mCi point source.
    • 1.0 cm ........... 760.00 mR/hr
    • 10.00 cm ....... 7.6 mR/hr
    • 100.00 cm...... 0.076 mR/hr
    • 6.0 in.............. 3.270 mR/hr

External Hazard

  • External and internal exposure and contaminate hazard.

Internal Hazard

  • Critical Organ: Total Body
  • Carrier or compound (radiopharmaceutical dependent)

Shielding

  • 1/4" to 1/2" lead shielding is adequate for Tc-99m 140 keV gammas

Safety Guidelines

  • Tc-99m is used in clinical and research diagnostic scanning and imaging.
  • Always wear lab coat and disposable gloves.
  • Whole Body and ring dosimeters are required.

updated 1/2013