SAFE HANDLING GUIDE Chromium-51 Handling Precautions Cr 27.7 d EC γ0.320 E0.752 51 This document contains general information designed to provide a basic understanding of radiation safety. While we believe the information to be accurate, regulatory requirements may change and information contained herein is not tailored to individual needs. A radiation protection specialist should be consulted for specific applications. Physical data Dosimetry Principal radiation emissions Gamma: 0.320 MeV (9.8%) X-ray: 0.005 MeV (22.3%) Auger electron: 0.004 MeV (66.9%) Unshielded exposure rate at 1 cm from a 1 mCi point source: 0.18 R/h(2) Unshielded exposure rate at 1 m from a 1 MBq point source: 0.13 nC/kg/h Half-value layer for lead shielding: 1.7 mm (0.067 in)(2) (1) Gamma emissions from 51Cr presents an external dose hazard. The retention of uptakes of 51Cr in the body is very dependent on its chemical form(4). It may be assumed that uptakes of 51Cr are retained in the transfer compartment with a biological half-life of 0.5 days(4). 5% of the uptake is then transferred to bone and retained with a biological half-life of 1000 days. 30% is directly excreted. 65% is distributed to other organs and tissues in the body; with 40% of the uptake retained with a biological half-life of 6 days and 25% retained with a biological half-life of 80 days(4). Occupational limits(3) Annual limit on intake: 40 mCi (1.5 GBq) for oral ingestion and 20 mCi (740 MBq) for inhalation Derived air concentration: 8 x 10-6 µCi/ml (300 kBq/m3) Decay table Physical half-life: 27.7 days(1). To use the decay table, find the number of days in the top and left hand columns of the chart, then find the corresponding decay factor. To obtain a precalibration number, divide by the decay factor. For a postcalibration number, multiply by the decay factor. Visit www.perkinelmer.com/toolkit to use our online Radioactive Decay Calculator. Days 0123456789 Days 0 1.0000.9750.9510.9280.9050.8820.8610.8390.8190.798 10 0.7790.7600.7410.7220.7050.6870.6700.6540.6380.622 20 0.6060.5910.5770.5630.5490.5350.5220.5090.4960.484 30 0.4720.4610.4490.4380.4270.4170.4060.3960.3870.377 General handling precautions for Chromium-51 1.Designate area for handling 51Cr and clearly label all containers. 2.Store 51 Cr behind lead shielding. 3.Wear extremity and whole body dosimeters while handling mCi (37 MBq) quantities. 4.Use shielding to minimize exposure while handling 51 Cr. 5. Use tools to indirectly handle unshielded sources and potentially contaminated vessels. 6. Prohibit eating, drinking, smoking and mouth pipetting in room where 51Cr is handled. 7. Use transfer pipets, spill trays and absorbent coverings to confine contamination. 8.Handle 51Cr compounds that are potentially volatile or in powder form in ventilated enclosures. 9.Sample exhausted effluent and room air by continuously drawing a known volume through membrane filters. 10.Wear lab coat, wrist guards and disposable gloves for secondary protection. 15. Establish surface contamination, air concentration and urinalysis action levels below regulatory limits. Investigate and correct any conditions that may cause these levels to be exceeded. 16. On completing an operation, secure all 51Cr, remove and dispose of protective clothing and coverings, monitor and decontaminate self and surfaces, wash hands and monitor them again. 51 Cr is slowly eliminated from the body. Whole body counting provides a more sensitive method than urinalysis for determining 51 Cr body burdens. Whole body counting may be used occasionally to verify the urinalysis results. References 1.Kocher, David C., Radioactive Decay Data Tables, Springfield: National Technical Information Service, 1981 DOE/TIC-11026. 12. Use end-window Geiger-Mueller detectors, NaI(Tl) detector or liquid scintillation counter to detect 51Cr. 2.Calculated with computer code “Gamma” utilizing decay scheme data from Kocher(1) and mass attenuation coefficient for lead and mass energy absorption coefficients for air from the Radiological Health Handbook, Washington: Bureau of Radiological Health, 1970. The HVL reported here is the initial HVL for narrow beam geometry. 13.Submit urine samples for bioassay at least four hours after handling 51Cr to indicate uptake by personnel. 3.U.S. Nuclear Regulatory Commission. 10 CFR 20 Appendix B – Standards for Protection Against Radiation, 1994. 14. Isolate waste in clearly labeled, shielded containers and hold for decay. 4.ICRP Publication 30, Part 2, Limits for Intakes of Radionuclides by Workers. Pergamon Press, Oxford, 1980. 11.Maintain contamination and exposure control by regularly monitoring and promptly decontaminating gloves and surfaces. PerkinElmer, Inc. 940 Winter Street Waltham, MA 02451 USA P: (800) 762-4000 or (+1) 203-925-4602 www.perkinelmer.com For a complete listing of our global offices, visit www.perkinelmer.com/ContactUs Copyright ©2007-2011, PerkinElmer, Inc. All rights reserved. PerkinElmer® is a registered trademark of PerkinElmer, Inc. All other trademarks are the property of their respective owners. 007031C_01 Oct. 2011