Half-life: 163 days
Type of decay and Energy: Beta () particle, 0.257 Mev (max)
Range in Air: 50 cm
Range in Water: 0.06 cm
Dose rate for typical quantities: No significant external exposure hazard.
Recommended Shielding: Plastic shield, any thickness, absorbs all beta particles.
Special Considerations: The low energy particles emitted from
Ca-45 have a minimal penetration fraction for protective gloves or the outer layer of skin.
Internal uptake is the primary concern since the critical organ is the bone. The annual limit on intake (ALI) is 2 mCi for oral ingestion or 800 µCi for inhalation.
Carbon-14
Half-life: 5730 years
Type of decay and Energy: Beta particle, 0.156 Mev (max)
Range in Air: 25 cm
Range in Water: 0.03 cm
Dose rate for typical quantities: No significant external exposure hazard.
Recommended Shielding: Plastic shield, any thickness, absorbs all beta particles.
Special Considerations: The low energy particles emitted from
C-14 have a minimal penetration fraction for protective gloves or the outer layer of skin.
Internal uptake is the primary concern since the critical organ is the bone for carbonates and body fat for many other compounds. The annual limit on intake (ALI) for compounds is 2 mCi for oral ingestion or for inhalation.
Hydrogen-3
Half-life: 12.7 years
Type of decay and Energy: Beta particle, 0.019 Mev (max)
Range in Air: 0.6 cm
Range in Water: 0.0006 cm
Dose rate for typical quantities: No external exposure hazard.
Recommended Shielding: None required
Special Considerations: The low energy particles emitted from
H-3 cannot penetrate the outer dead layer of skin.
Internal uptake is the primary concern since the critical organ is the whole body water. The annual limit on intake (ALI) is 80 mCi for oral ingestion or for inhalation.
Iodine-125
Half-life: 60 days
Type of decay and Energy: Gamma Rays, 35 keV (7% of decays)
k-shell x-rays, 27-32 keV (140% of decays)
Range in Air: 50 cm
Range in Water: 0.06 cm
Dose rate for typical quantities: 1.4 R per hour at 1 cm away from 1 mCi.
Recommended Shielding: Lead foil, 1mm thick, absorbs 99+% of photons
Special Considerations: Store NaI solutions at room temperature to minimize volatilization of compounds. Avoid acidic solutions.
The thyroid is the critical organ for uptake. The annual limit on intake (ALI) for the thyroid is
40 µCI for oral ingestion or 60 µCi for inhalation.
Phosphorus-32
Half-life: 14 days
Type of decay and Energy: Beta particle, 1.709 Mev (max)
Range in Air: 790 cm
Range in Water: 0.8 cm
Dose rate for typical quantities: 26 rem per hour at the mouth of an open 1 mCi vial in 1 ml of liquid.
Recommended Shielding: Plastic shield 1cm thick absorbs all beta particles.
Special Considerations: Do not use lead shielding for high energy particles. This produces x-rays that are harder to shield.
The bone is the critical organ for uptake. The annual limit on intake (ALI) is 600 µCI for oral ingestion or 900 µCi for inhalation.
Phosphorus-33
Half-life: 25 days
Type of decay and Energy: Beta particle, 0.249 Mev (max)
Range in Air: 50 cm
Range in Water: 0.06 cm
Dose rate for typical quantities: No significant external exposure hazard.
Recommended Shielding: Plastic shield, any thickness, absorbs all particles.
Special Considerations: The bone is the critical organ for uptake. The annual limit on intake (ALI) is 6 mCi for oral ingestion or 8 mCi for inhalation.
Sulfur-35
Half-life: 87 days
Type of decay and Energy: Beta particle, 0.167 Mev (max)
Range in Air: 26 cm
Range in Water: 0.03 cm
Dose rate for typical quantities: No significant external exposure hazard.
Recommended Shielding: Plastic shield, any thickness, absorbs all beta particles.
Special Considerations: S-35 amino acids can decompose to volatile compounds during storage. Always open stock vials in an operating chemical fume hood.
Incubation of S-35 methionine may release volatile compounds. The incubator may become contaminated.
The low energy particles emitted from
S-35 have a minimal penetration fraction for protective gloves or the outer layer of skin.
Internal uptake is the primary concern since the critical organ is the whole body. The annual limit on intake (ALI) for most compounds is 10 mCi for oral ingestion or 20 mCi for inhalation.