Radioactive Materials Safety Manual

47 Radioactive Materials Safety Manual 32P PHOSPHORUS-32 Half - Life Physical Biological Effective 14.3 days 1,157 days (bone) 14.1 days (bone) Radiation Emitted Type Energy (max) Range (max) Beta 1.71 MeV Air: 6m Tissue: 8 mm Bremsstrahlung 1.71 MeV Infinite (theoretical) External Hazard 1 meter Surface Dose rate from a 1 mCi (37 MBq) point source: 9.1 µrad/hr (.091 µGy/hr) 780 rads/hr (7.8 Gy/hr) Dose rate to live skin from 1 µCi/cm2 (.037 MBq/cm2) skin contamination: 9.2 rad/Hr (92 mGy/hr) Internal Hazard Effective Committed Dose Ingestion Inhalation Equivalent per Unit Intake: 8.8 mrem/µCi (2.37 x 10-9 Sv/Bq) 6.1 mrem/µCi (1.64 x 10-9 Sv/Bq) Annual Limit on Intake: (ALI)* 600 µCi 900 µCi *ALIs expressed are from Appendix B, Table 1 – Iowa Administrative Code 641.40 (136C). Special Considerations • 32P emits the highest energy beta particle of any commonly used radionuclide. • Relatively small quantities of 32P (microcuries) can result in extremely high external dose rates to live skin and underlying tissue when the distance between the source and skin is short (a few centimeters or less). • The interaction of 32P beta particles with matter can result in the production of high levels of bremsstrahlung which may require the use of lead shielding (this is particularly true if quantities of 10 mCi (370 MBq) or more are used).