Radionuclide Safety Data Sheets
Phosphorus - 33(33P)
|Beta Energy:||249 keV (maximum)
85 keV (average)
|Physical Half-Life:||25.4 days|
|Biological Half-Life:||1155.0 days|
|Effective Half-Life:||24.9 days|
|Maximum Beta Range in Air:||51.00 cm = 20 inches|
|Maximum Beta Range in Water / Tissue:||0.06 cm = 0.025 inches|
|Maximum Range in Plexiglas / Lucite / Plastic:||0.05 cm = 0.020 inches|
|Half-Value Layer (HVL):||0.008 cm (water / tissue)|
|NOTE:||(1) A beta with an energy of 795 keV can penetrate to the lens of the eye (0.3 cm) depth.
(2) A beta particle with an energy of > 70 keV is required to penetrate the dead layer of skin.
(3) Rule of Thumb:
• 250 keV betas can penetrate about 0.6 mm of tissue/water
[Fraction of P-33 beta particles transmitted through the dead layer of skin (0.007 cm) ~35%]
- Critical Organ (soluble form): Bone marrow
- Critical Organs (insoluble forms or non-transportable P-33 compounds): Lung (inhalation) and G.I. Tract/Lower Large Intestine (ingestion)
- Routes of Intake: Ingestion, Inhalation, Puncture, Wound, Skin Contamination (Absorption)
- Internal exposure & contamination are primary radiological concerns
|Committed Dose Equivalent (CDE):||0.5 millirem / uCi (inhalation)|
|Annual Limit on Intake (ALI):||6 millicuries (oral ingestion)
8 millicuries (inhalation / Class "D")
3 millicuries (inhalation / Class "W")
- [1.0 ALI = 6 millicurie (ingested) = 5,000 millirem CEDE (Whole Body)]
|Skin Contamination Dose Rate:
(Dose Rate to Basal Cells)
|2,659 mrem/hour per 1.0 uCi/cm2
(7 mg/cm2 or 0.007 cm depth in tissue without air reflection)
Skin Contamination Dose Rate (Extremity Skin): P-33 betas cannot penetrate 0.3 cm or 30 mg/cm2 of tissue
- Tissues with rapid cellular turnover rates show higher retention due to concentration of phosphorus in the nucleoproteins.
- P-33 is eliminated from body primarily via urine.
|Phosphorus Metabolism:||30% is rapidly eliminated from body
40% has a 19-day biological half-life
60% of P-33 (ingested) is excreted from body in first 24-hours;
only about 1% per day is excreted after the 2nd or 3rd day.
SHIELDING: Not Required; however, low-density (low atomic number) material is recommended (> 3/8” of plexiglas, acrylic, plastic, or plywood).
- Use G-M survey meter and pancake / frisker probe (15.5 cm2 area). Counting efficiency is approx. 6% for P-33 beta energy (249 keV)].
- Liquid scintillation counter (indirect counting) should be used to detect removable P-33 contamination on smears or swabs.
PERSONAL RADIATION MONITORING DOSIMETERS: Not Required (beta particle is too weak)
REGULATORY COMPLIANCE INFORMATION (10 CFR 20 / Appendix B)
|Derived Air Concentration (DAC):
|4.0E-6 uCi/mL (Class "D")
1.0E-6 uCi/mL (Class "W")
|Airborne Effluent Release Limit:*
|1.0E-8 uCi/mL (Class "D")
4.0E-9 uCi/mL (Class "W")
* Applicable to the assessment & control of dose to the public (10 CFR 20.1302). If this concentration was inhaled or ingested continuously over one year it would produce a TEDE of 50 millirem.
- Urinalysis: Not Required; however, may be requested by RSS personnel after a radioactive spill of P-33 or a suspected intake.
- Unrestricted Area removable Contamination Limit: 1,000 dpm / 100 cm2
- Container Labeling Requirement [10 CFR 20.1905]: ≥ 100 uCi
GENERAL RADIOLOGICAL SAFETY INFORMATION
- Inherent Volatility (STP): Insignificant
- Skin dose, internal contamination, and area contamination are the primary radiological concerns.
- Drying can form airborne P-33 contamination.
- Always wear a lab coat and disposable gloves when handling P-33.
- Monitor work areas for removable surface contamination by smearing, swabbing, or wipe testing where P-33 is used. Count smears or swabs in a liquid scintillation counter (LSC).