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Technicium 99

Beta Max Half Life
0.1013 MeV Mean energy 2.111 x 105 years
0.2935 MeV Max energy  

In Use

The following quantities will give a dose rate of 2 mSv/h without shielding.

  • If handled at distances of 10 cm or more 3 MBq
  • If handled at distances of less than 10 cm 30 KBq

Note that these quantities may be handled for a maximum of 15 minutes per day, five days a week, before the dose rate to the fingers is exceeded.

Effective Dose Coefficients

Inhalation coefficient Ingestion coefficient Skin dose coefficient
2.9 x 10-10 Sv.Bq-1 - 1μm AMAD, fast clearance 7.8 x 10-10 Sv.Bq-1 3.38 x 10-10 Gy.s-1 per Bq.cm-2 

Classification

If the total quantity of technicium - 99 in the laboratory is over 50 MBq, it is necessary to classify the laboratory as a controlled area.

If the total quantity of technicium - 99 in the laboratory is over 10 MBq it is necessary to classify the laboratory as a supervised area.

*50 MBq if inhaled would give rise to an effective dose of 15 mSv.