John Gough, MS, CHP
Radiation Safety Officer
Swedish Medical Center

• Established in 1910
• 3 Hospital locations
• Multiple specialty clinics
• Cancer, Heart, Surgery institutes
• 12 primary-care clinics
• Full range nuclear med, radiation oncology
• Research Hospital
• Type A Medical Broad Scope License

• X-rays discovered in 1895
• Radioactivity discovered in 1896
• First document radiation fatality – 1904
– Clarence Daly severely burned in
1986 by an x-ray fluoroscope

• First attempt at establishing a radiation dose limit – Skin Erythema Dose – 1920
• 200 mR/day dose limit established in 1931
• 25,000 mrem/year established during
WWII.

• scientific determination of amount, rate, and distribution of radiation emitted from a source of ionizing radiation, in biological d.
measuring the radiation-induced changes in a body or organism, and in physical d.
measuring the levels of radiation directly with instruments.

• Immediate Read
– Pocket Ionization Chambers, Solid state detectors, handheld GM/Ionization detectors with dose accumulation function
• Delayed read / Personnel monitors
– Film Badges, TLD (Thermo Luminescent
Dosimeters), OSL (Optically Stimulated Lightemitting Dosimeters)

• Most common type of radiation dosimeter used.
• Works by darkening of x-ray film in proportion to radiation absorbed.
• Cheap
• Not durable
• Short monitoring period per badge (6 months or less)

• “Captures” radiation dose information in a crystal matrix
• Releases light when heated, light intensity proportional to radiation dose absorbed
• Durable
• Can be expensive (reusable chips)
• Information destroyed when processed

• “Captures” information in an Aluminum
Oxide matrix
• Releases information by laser stimulation
• Can be reread after processing
• Durable
• Landauer Only

• Electro-statically charged “leaf” discharges as it is exposed to ionizing radiation
• Not considered a “legal” record
• Low accuracy (+/- 20%)
• Physical impacts can affect radiation dose readings

• Provides instantaneous information regarding dose accumulation
• Simple to use
• Not a “legal” record
• Dose range device dependent

• Ability to perform both dose rate and dose accumulation
• Good for spot checks
• Direction dependent
• Not considered a “legal” personnel dose record

"Occupational dose" means the dose received by an individual in the course of employment in which the individual's assigned duties involve exposure to radiation or to radioactive material from licensed and unlicensed sources of radiation, whether in the possession of the licensee, registrant, or other person. Occupational dose does not include dose received: From background radiation, from any medical administration the individual has received , from exposure to individuals administered radioactive material and released under chapter 246-240 WAC, from voluntary participation in medical research programs, or as a member of the public.

Activity
1 day of background radiation
1 Chest x-ray
Public Dose Limit
Nuclear Stress Test
Whole Body CT
Dose (mrem)
1 mrem
10 mrem
100 mrem
500+ mrem
1000+ mrem

Part of Body
Whole Body (TEDE)
Organ or Extremity
Lens of the Eye
Dose to Fetus
Annual Limit
(mrem)
5,000
50,000
15,000
500

Part of Body
Whole Body (TEDE)*
Organ or Extremity
Lens of the Eyes
Annual Limit
(mrem)
5,000*
50,000
15,000
* Not to exceed 1000 mrem x Individual’s Age for
Cumulative Lifetime exposure.

“As Low As Reasonably Achievable” means making every reasonable effort to minimize the dose received when working with sources of radiation. Essentially it means minimizing the risks while understanding that the cost vs. benefit for the dose reduction.

Part of Body
Whole Body
Organ or Extremity
Lens of the Eyes
Fetal
Quarterly Action Level
(mrem)
Level I Level II
125
1250
375
3750
375 n/a
1125
150

Isotope
Ir-192
Co-60
Se-75
X-ray
Typical
Activity (Ci)
100
Gamma
Constant (R/hr
– Ci @1 meter)
0.48
Dose rate
(R/hr @ 1m)
48
20 1.32
26.4
0.2
20 100 n/a