Lec #1 - Principles of Radiation Protection

Question 1

What do we shield patients from?

Answer 1

-shield pt for off focus radiation not scatter.

Question 2

What are the 4 main aspects of radiation safety?

Answer 2

1. No unnecessary radiation
2. Shield when possible
3. protect personnel
4. general public require protection

Question 3

What does a low DI vs high DI indicate?

Answer 3

Low DI (-1) – quantum mottle (under exposed
High DI (+3) - saturation of image (over exposed)

Question 4

What does ‘should’ vs ‘must’ mean for radiation protection

Answer 4

• “Should” vs. “must”, recommendation vs. directive, seen in SC35, HARP

Question 5

What do dose limits account for?

Answer 5

• DL is occupational dose only.

Question 6

What is the dose limit for the whole body (radiation worker vs public)

Answer 6

worker - avg 20 mSv per year over 5 (100 total) max of 50 per year

Public - 1 mSv

Question 7

What is the dose limit for the lens of the eye (radiation worker vs public)

Answer 7

worker - 20 mSv per year (100 in 5 years) - max 50 in 1 year

public - 15 mSv

Question 8

What is the dose limit for the skin (radiation worker vs public)

Answer 8

worker - 500 mSv
public - 50 msV

Question 9

What is the dose limit for the hands and feet (radiation worker vs public)

Answer 9

worker - 500 mSv
public - ?

Question 10

How can you reduce dose to pt and operator?

Answer 10

1. Technique, collimation
2. Shielding, distance (also want to reduce scatter)

Question 11

What is the amount of radiation a pregnant women can receive after declaring pregnancy?

Answer 11

• 4 mSv for remainder of pregnancy

Question 12

How long should dosimetry records be kept?

Answer 12

dosimetry records must be maintained for the lifetime of the facility.