1. Radiation Safety Lavin: Chapter 16 CTVT: 566-570
Test Friday– Must pass with an 80% to be able to participate in labs

2. Learning Objectives: Chapter 16
Understand radiation risks
Differentiate ALARA and maximum permissible dose
Understand the use of personal exposure dosimeters
List practical methods personnel can use to reduce exposure
Describe and understand the importance of personal protective equipment (PPE)

3. Radiation Doses to Staff
ALARA
NOT a set number, but a general guideline
The workplace program developed to ensure that radiation dosages are kept as low as possible
Governs everything we do in lab
Setting exposure factors
Protecting ourselves and patients
National Council on Radiation Protection & Measurements
Governmental body that sets standards for radiation safety

4. What are the dangers?
Concern is not high doses, it’s the diagnostic dose over time
Human body = 80% water
Liquid is a conductor of electricity
Radiation targets DNA
Especially rapidly growing/dividing cells
Young people
Unborn babies
Certain tissues/organs are more susceptible

5. Radiation targets DNA…
Radiation is nonselective – affects where it hits
3 things can occur:
No immediate effect – latent effects
Cell is damaged – repairable or not
Cell death
Main concern is “latent” effects
No recorded cases of death from diagnostic x-ray exposure (today’s safety standards)
Biggest risk to personnel: ___________ effects
Malignancy
Genetic effects

6. Two Causes of Radiation Danger
1. Primary – Direct exposure to the primary beam
2. Secondary (scattered radiation)
Photons still have energy after penetrating patient
Produce radiation from atoms in the patient
*Most important impact on healthcare workers
What can increase the amount of scattered radiation?
Why is scattered radiation more of a danger than primary?

7. Tissue Damage from Radiation
Two types of tissue damage:
Somatic – Occurring within the life of the individual
Genetic – Occurring in future generations (gene mutations)
Organ systems most sensitive:
Reproductive organs
Hematopoietic cells
Thyroid gland
Intestinal epithelium
Lens of the eye
Developing fetus

8. Legal Prohibitions Prohibited from exposing radiographs:
Individuals under age 18
Declared pregnant women
Most critical time is first trimester: period of organogenesis
No safe limit has been determined
Concerns in clinic should be directed to your Radiation Safety Officer
VTI = Ms. Huff
*If you are pregnant, see me ASAP!

9. Maximum Permissible Dose (MPD)
The dose the NCRP has determined should not harm the person receiving it over their lifetime
The maximum permissible dose for occupational whole- body radiation/year that is allowed by law:
MPD = 5 rem/year
Sievert (sv) = the unit for dose equivalent
Dose of radiation equivalent to the absorbed dose in tissue
1 sv = 100 rem

10. MPD (cont.) Other radiation dosage units: How much is too much?
Gray (Gy) – Unit of absorbed dose
Amount of radiation needed to deposit 1 joule of energy into 1 kg of matter
How much is too much?
No one really knows
Dose limits for non-radiation workers > radiation workers
Radiation worker: An individual who could be exposed to radiation from man-made sources during their work

11. ALARA ≠ MPD ALARA: As Low As Reasonably Achievable
NOT a set number but a general guideline
No set safe amount is known
“Keep exposure as low as possible”
MPD: Maximum Permissible Dose
Amount of ionizing radiation a person may be exposed to supposedly without being harmed
Is a set number
Assumed to be safe, but no one knows for sure

12. Minimizing Exposure 3 rules of protection:
Time – Minimize time spent near radiation sources
Distance – Maximum practical distance from radiation source
Shielding – Placing a shield between the subject and source

13. Minimizing Exposure: Time
Reducing time is an important factor
Use the shortest exposure time possible
Use the fastest film-screen combination
Use a customized technique chart
Dosimeters must be worn by anyone working with or in the vicinity of an x-ray machine
Measures radiation dose for one person in one location over time

14. Minimizing Exposure: Distance
What determines the intensity of radiation at a given distance?
Maximizing distance:
Maximize distance from you to the primary beam
Lean/turn head away from the beam
Exit the room, if possible
Sandbags or other mechanical restraint
Sedate if needed

15. Minimizing Exposure: Shielding
Positioning a barrier between you and the radiation source greatly reduces the level of radiation exposure.
What you can do:
Wear aprons, gloves, glasses, thyroid shield, etc.
Wearing gloves provides no protection from primary x-ray beam!

16. Personal Protective Equipment (PPE)
Made of thin sheets of lead layered together
Minimum safe lead thickness is 0.79 mm
VTNE Prep materials and old edition say 0.5 mm…
Use & care of PPE:
Hang aprons up by the shoulders
No folding or creasing!
Clean regularly - warm water/mild soap
Should fit correctly and be tied tightly
Shoulders AND waist
Treat thyroid collars with the same respect
Eye wear should be stored in protective case

17. Personal Radiation Dosimeters
Whole body dosimeters
Worn above the waist but below the head
Monitors exposure of the thyroid and lenses of the eye
Outside other protective equipment
Extremity dosimeters
Fetal dosimeters
Worn in conjunction with other gear
Worn on the belly under other equipment
Film badge
Thermoluminescent (TLD)

18. Dosimeters Thermoluminescent dosimetry:
Registers a charge over time if exposed to radiation
Rules of usage:
Remain in radiology room at all times
Store away from radiation
Store away from heat, sunlight
Must be worn EVERY time you are in
the lab while exposure is happening
Attach outside of thyroid collar