Principles of Radiation Protection

Question 1

Xray discovery when?

Answer 1

1895

Question 2

what is the purpose of radiation protection?

Answer 2

Ionizing radiation can cause
injury in human tissue
Must reduce the potential
likeliness of harmful biological effects

Question 3

four main aspects of radiation safety

Answer 3

1. patients should not be subjected to unnecessary radiographic procedures
2. the patient must be protected from excessive radiation exposure
   during the examination.
3. personnel within the facility must be protected from excessive exposure to radiation during the course of their work.
4. personnel and the general public in the vicinity of such facilities require adequate protection

Question 4

Cardinal principles of radiation

Answer 4

1. Time
   Patient: reduce the amount of x-ray beam ‘on’ time, reduce repeats (reciprocity
   does not apply)
   Personnel: shortening length of time in room
2. Distance
   Patient: maximize distance
   Personnel: maximize distance ex. mobiles
3. Shielding
   Patient: appropriate gonadal and or specific area shielding if required
   Personnel: behind lead walls/protective barriers

Question 5

Concepts of Dose Limits (DL’s)

Answer 5

The concept of radiation exposure and of the associated risk of
radiation-induced malignancy is the basis of the effective dose
limiting system
Medical imaging professionals must be familiar with previous,
existing, and new guidelines for radiation safety
- They share the responsibility for patient safety from radiation exposure.
- They are subject to radiation exposure in the performance of their duties.
Advisory groups

Question 6

Advisory Groups

Answer 6

Advisory groups and regulatory agencies involved in formulating risk
estimates of somatic and genetic effects of irradiation
Create language around radiation principles
Focus of Agencies (for Radiography) - Genetic damage

Question 7

Directive vs. Recommendation

Answer 7

Protective gonad shields for patients must have a lead equivalent of at
least 0.25 mm Pb and should have a lead equivalent thickness of 0.5
mm at 150 kVp.

Question 8

Radiation Measurements

Answer 8

Exposure- Coulomb per kg (C/kg) or milliroentgen (mR)
Absorbed Dose - milligray (mGy)
Effective Dose - millisievert (mSv)

Question 9

Dose Limits

Answer 9

Occupational
others (public)

Question 10

Dosimeters

Answer 10

worn by occupationally exposed personnel - anyone at risk of exceeding Public DL of 1 mSv
TLD always worn under lead apron
additional dosimeters may be required if pregnant