Radiation Protection in the biomedical laboratory- biennial update

1. Radiation Protection in the biomedical laboratory- biennial update Dept. of Health Physics and Radiopharmacology Brigham and Women’s Hospital

2. Refresher tutorial - purpose • provide update of BWH radiation safety policies and initiatives • review of lab practice • compliance with regulatory requirements

3. Responsibility for Radiation Safety U.S. Nuclear Regulatory Commission • Guidance documents and model procedures at www.nrc.gov Mass. Dept. of Public Health - Radiation Control • Inspects, regulates, enforces regulations of 105CMR.120 Radiation Safety Committee – BWH • Reviews protocols, exposures, events, authorizes users

4. Responsibility for Radiation Safety Radiation Safety Office • Consult, audit, assist with requirements of radiation protection program PI/Permit holder • Responsible for safe and appropriate use of radioactive materials in lab, may delegate/appoint radiation safety liaison Individual user • Uses radiation protection guidelines and protocols (PPE, routine surveys, etc.)

5. Additional responsibilities – radiation user • Check packages for removable contamination – log results • Safe handling, with attention to good laboratory practices (e.g., no eating, drinking in lab area, protective equipment worn, radioactive materials labeled and secured, etc.) • Consolidate and isolate radiation work areas/benches • Maintain a calibrated and functional radiation detector • Conduct regular surveys of lab (work surfaces, equipment) and personnel (clothing, hands, shoes) • Proper waste disposal

6. Occupational dosimetry • Staff and trainees working with ionizing radiation are issued bi-monthly radiation dosimeters (a single whole body badge) • The badges will be delivered several days prior to the beginning of every other month. Once you have collected the new badge, remove the current badge and return them to Health Physics by the 10th of the succeeding month. • A monthly dosimetry report posted in your lab contains your personal dosimetry (deep dose, eye dose, and shallow dose) for the month, the last quarter, the year-to-date, and full BWH lifetime, e.g., 4-5 years of cumulative exposure/ residency. • A dose value of M = minimal dose (< 1 mrem).

7. Sample report from vendor

8. Maximum permissible annual dose limits Whole body = 5,000 mrem/yr Eyes = 15,000 mrem/yr Skin = 50,000 mrem/yr If pregnant: ≤ 500 mrem for the declared pregnancy period ≤ 50 mrem/month

9. BWH - all for 2008

10. BWH –Research staff (2009) Max. dose = 32 mrem (<1% max. permissible dose)

11. Radiation spill protocol • Unsealed sources should be handled over absorbent pads, with impermeable gloves, and appropriate warning signs/labels • Nevertheless, spills occasionally happen, though if promptly contained and reported, rarely pose a significant problem

12. Radiation spill protocol • In the event of a spill, try and contain the spilled volume with absorbent pads, and limit access to the area • Clean from the outside area , working inward • Check gloves and replace, as needed • Resurvey or re-wipe until manageable radiation levels attained • Isolate all contaminated materials • Hand-washing with warm, soapy water removes 90% of radiocontamination *Contact the RSO for assistance in decontamination and area monitoring

13. Geiger-Müller (GM) detector use (gamma and high energy beta emitters) • Check calibration date (annual calibration requirement) • Test battery • Turn sound on • Determine background level (usually 0.02-0.05 mR/hr, or, 40-100 cpm with GM) • Place as close to monitored area as is practical (within 1 inch) • Move the probe at 1-2 inches / second • Record exposure values • If ≤ 2x bgd; = not contaminated and no further action required • If > 2x bgd; decontaminate and resurvey

14. Inverse square relationship implies that the intensity of the radiation significantly drops off with distance from the source Example 5.0 mR/hr @ 0.3 m. Change the distance from 0.3 m to 0.6 m What is the resulting exposure rate? 5.0 mR/hr = (0.6 m)2 ? mR/hr (0.3 m)2 = 1.25 mR/hr @ 0.6 m Distance changes by a factor of 2….Exposure reduced by a factor of 4.0

15. Waste disposal guidelines • Deface all radioactive labels for materials no longer radioactive (e.g., packaging) • Reduce volume; do not place non-radioactive packaging materials or Pb containers in waste • Place needles, broken glass, and other hazards in sharps box • 3H and 14C can be mixed together (for shipping to long-lived disposal facility)

16. Waste disposal guidelines • Segregate scintillation vials from other waste • Liquid and solid waste segregated • Use an abundant amount of absorbent materials so that the liquid is completely absorbed (reduces spill/contamination potential) • All other rad waste segregated in radionuclide-specific bins, e.g.,125I box, 32P box

17. Adhere to radionuclide-specific daily limits Record disposals Maintain records Inadvisable for radio-iodine Designated “hot sink” is also a disposal option,provided that users:

18. Radionuclide T 1/2 Emission Detector Shielding Cautions 3H 12.2 years b 0.18 KeV Liquid Scintillation counting ______ Not easily detected. Could be hazardous if internalized 14C 5730 years b 50KeV LSC or GM ______ Same as above 32P 14.3 days b 1710 KeV (maximum) 700 KeV (average) GM Plastic > 3/8” Use plenty of shielding and safety eyewear 33P 25.3 days b 80 KeV (average) GM Plastic Less energetic than 32P 35S 87.9 days b 49 KeV (average) GM (if >250 mCi ) Plexiglas depending on quantity 51Cr 27.8 days 320 KeV GM or Nal Lead > ¼” High energy , use plenty of shielding 125I 60.2 days 35 KeV Nal Lead >1/10” Internal hazard to thyroid.

19. Summary-radiation protection in biomedical research labs • Most significant hazard is contamination • Skin • Clothing • Work surfaces • Control and Precautionary Measures • PPE (gloves, lab coat) • Routine area and personnel surveys • Wipe tests, as needed