Working with Radioisotopes: Reducing the Risk

UW Radiation Safety Manual

Chapters 2, 3 and 4

http://nuclearchem.wikispaces.com/file/view/radioactivity_atom.jpg/30290660/radioactivity_atom.jpg

Radioisotopes as biological hazards

• high energy beta emitters: both external and internal hazards

• low energy beta and alpha emitters: internal hazards only

http://s2.hubimg.com/u/4824005_f520.jpg

Biological Half-life

• T 1/2B: the time required for the body to reduce the amount of a chemical or substance to one-half its original amount

Effective Half-life

• At the same time, in the case of a radioisotope, the isotope is decaying according to its physical half-life

• Biological and physical half-lives combined give an effective half-life which reflects the amount of time that isotope is damaging the body

Effective Half-life

http://www.ionactive.co.uk/uploadedimages/ionactive_dose_internal_03_400.jpg

Working with radioactivity

• Risks?– Unclear– Some studies suggest low risk

The risks of low-level exposure

The knowledge is lacking

http://1.bp.blogspot.com/_8adFNycaanI/Sfg9tEgeENI/AAAAAAAAAoU/yHyRa-JeCUI/s400/Leukemia2.JPG

The linear, no-threshold model

• Regulatory agencies use a linear, no threshold model to predict effects of radiation

http://nuclearsafety.gc.ca/eng/mediacentre/perspectives/no_threshold_image1_eng.jpg

Occupational risk factorsHealth risk Estimated loss in life expectancySmoking 20 cigs/day 6 yearsOverweight (15%) 2 yearsAvg. alcohol intake 1 yearCar accidents 207 daysHome accidents 74 daysNatural disaster 7 daysMedical diag. radiation 6 daysAvg. rad. worker 15 daysAgriculture 60 daysConstructions 227 daysMining 167 daysManufacturing 40 days

Sources of radiation exposure

The average American receives a dose of 357 mrem per year.

http://www.umich.edu/~radinfo/images/doseus.gif

• 82% of this is from natural exposure sources

• Man-made: Major source is medical or dental

Basic principles of protection

• TIME, DISTANCE, SHIELDING

http://www.nrc.gov/images/about-nrc/radiation/time-distance-shielding.gif

Types of shielding• Different isotopes require different materials and

thicknesses of shields

http://www.coal2nuclear.com/Radiation%20Types%202%20-%20Short.gif

Safety Guidelines • Always wear protective clothing• Monitor frequently.• Remove gloves and wash hands when

finished.

http://upload.wikimedia.org/wikipedia/commons/4/40/Geiger_counter.jpg

Safety Guidelines

• Do work in a fume hood if gas, vapor, dust or aerosols can occur during the procedure.

• Do not eat, drink, etc

• Do not mouth pipette

http://www.facilities-buffalo.org/files/EHS/images/rad/caution-RAM.jpg

Safety Guidelines

• Lock and secure stock vials when not in use.

• Do not store food or drink containers in the same location as radioactive materials.

• Do not bring personal belongings into the radioactive work areas of the lab.

http://www.taylorscientific.com/taylorscientific/Assets/ProductImages/13-9830.jpg

Safety Guidelines

• Always wear dosimeter

• Bandage cuts

• Watch for contamination of containers

http://dwb.unl.edu/teacher/nsf/C03/C03Links/www.dac.neu.edu/oehs/slide45.jpg

Safety Guidelines

• Employ the three basic safety principles of time, distance and shielding.

• Contain any spills

http://www.ndt-ed.org/EducationResources/CommunityCollege/RadiationSafety/Graphics/TimeDistShield.gif

Safety Guidelines

• Monitor!!• Be familiar with properties of radioisotopes in

use

http://blink.ucsd.edu/_images/import/2/2769th.jpg