Stanford University

In-111 Radionuclide Fact Sheet

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Forms: All Soluble

Physical Characteristics:

Half-Life: 2.83 days

Type Decay: e capture

gamma: 0.171 MeV (90%) 0.245 MeV (94%)

X-rays: 0.022 – 0.026 MeV

Conversion electrons: to 0.244 MeV

Auger electrons: to 0.019 MeV

What are the hazards?

Hazard category:

  • C- level (low hazard ) : 100 uCi to 10 mCi
  • B – level (Moderate hazard) : > 10 mCi to 1 curie
  • A – level (High hazard) : > 1 Ci

External Radiation Hazards and Shielding:

The exposure rate at 1 cm from 1 mCi is 3200 mR/h. The exposure rate varies directly with activity and inversely as the square of the distance. Then tenth value of lead for this energy of radiation is 0.2 cm.

Hazards if Internally Deposited:

The annual limit on oral intake (ALI), based upon limiting weighted dose equivalent to the gonads, red bone marrow and G.I. tract, of In-111 corresponding to a whole-body guideline gamma exposure rate of 500 mrem/year is 540 uCi.

How can I protect myself?

When 5 millicuries are used, work behind lead shielding. Survey frequently. Handle stock solution vials in shields or use tongs or forceps. Change gloves often.

How do I dispose of this?

  1. Segregate wastes to those with half-lives less than 4 days.
  2. Dilute aqueous wastes may be disposed to the sewer system in amounts of up to 100 uCi daily per lab.

Dosimetry and bioassay requirements

Film badges and dosimeter rings are required if 10 millicuries are handled at any one time or 5 millicurie levels are handled on a frequent (daily) basis.

Urine assays may be required after spills or contamination incidents.

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