Phosporus-33 (P-33)

DOE-HDBK-1106-97

PHOSPHORUS-33 (P-33)

Phosphorus-33 is a low-energy beta emitter. Most common means of detection is with a thin-

window probe or liquid scintillation.

Maximum energy: 0.248 MeV; the average energy is 0.083 MeV.

Maximum range in air: 1.5 feet (0.5 m).

Maximum range in tissue: 1 mm.

IAEA toxicity classification: Medium-low.

Physical half-life: 24.4 days.

6. Effective half-life (Teff): 10-24 days.

7. Critical organ:

Bone for transportable compounds.

Lung and lower large intestine are critical organs for inhalation and ingestion,

respectively.

8. Personnel monitoring: NOT detected with a dosimeter (thermoluminescent dosimeter

or film) dosimeter and finger rings, uptakes may be determined by urinalysis.

9. ALI:

3 mCi (1 x 108 Bq) by inhalation, clearance in weeks.

6 mCi (2 x 108 Bq) by ingestion.

10. Shielding: 3mm of plexiglass (if needed).

11. Special considerations:

Detection of P-33 by radiation survey instruments requires special care due to the low

efficiency of detection.