Radiation/Imaging

Question 1

What’s most significant source of radiation during procedure?

Answer 1

Scatter

Question 2

Where is scatter greatest?

Answer 2

Below the table

Question 3

What’s most common organ affected by deterministic effect of radiation? By Stochastic?

Answer 3

Deterministic: skin, eyes
Stochastic: Thyroid, breast

Question 4

What’s a radiation “sentinel event”?

Answer 4

> 15 Gy to single field over 6 mo-1y
Radiation delivered to wrong area
Actual dose >25% above planned

Needs to be reported

Question 5

Where is most sensitive area of skin to radiation? Least sensitive?

Answer 5

Most: anterior neck
Least: Palm/soles

Question 6

What radiation typically leads to radiation induced skin injury? When should you prophylactically follow up?

Answer 6

2+ Gy.
Follow up for >5 Gy

Question 7

What are the signs/progression of radiation induced skin injury?

Answer 7

First sign: transient erythema
Radiation induced telangiectasia: rarely develops <1y after exposure

Question 8

What dose of radiation can lead to cataracts? What’s total recommended eye dose?

Answer 8

5+ Gy
<20 mSv averaged over 5 years

Question 9

What’s safe radiation exposure during pregnancy?

Answer 9

<50 mRem/month, <500 mRem/pregnancy