Radiation

Question 1

Describe Ionizing radiation

Answer 1

Energy that can dislodge electrons it can appear as gamma rays, x-rays, high-energy neutrons, & alpha or beta particles

Question 2

Radiation can be measure in 3 ways

Answer 2

Curie: Ci (Radiation emitted)
Gray: Gy (radiation absorbed)
Sievert: Sv (biological effect)

Question 3

1rad = _______
1cGy = _______
1Sv= _________

Answer 3

1rad = 100 erg
1cGy = 1 rad
1Sv= 1Gy gram

Question 4

Describe how rate of delivery can impact the biological effects of ionizing radiation

Answer 4

Fractioned doses of radiation induce less damage because repair is able to happen

Question 5

Describe how field size can impact the biological effects of ionizing radiation

Answer 5

A smaller field size can reduce complications with ionizing radiation exposure

Question 6

Describe how cell proliferation rate can impact the biological effects of ionizing radiation

Answer 6

Rapidly dividing cells are at less risk then quiescent cells

High risk cells:
- gonads
- Bone marrow
- Lymphoid
- GI mucosa

Question 7

Describe how vascular endothelium can impact the biological effects of ionizing radiation

Answer 7

It’s moderately sensitive to radiation & exposure to IR can lead to narrowed blood vessels or occlusions both of which reduce healing and increase fibrosis

Question 8

What effect does fractional radiation therapy have on the body?

Answer 8

Systemic inflammation

Question 9

Describe how oxygenation of irradiated tissues can impact the biological effects of ionizing radiation

Answer 9

Tissues with less oxygenation are more resistant to IR (less free radical dmg)

Question 10

Describe how fibrosis can impact the biological effects of ionizing radiation

Answer 10

Scar & adhesion formation result from IR therapy when the dead parenchymal cells are replaced with CT

Question 11

Describe the acute effects of ionizing radiation

Answer 11

• Free radicals
• DNA dmg
• P53 activation

Question 12

List tissues in order from most radiosensitive to least

Answer 12

1. Blood forming & reproductive organs
2. Gi tract & lungs
3. Skin
4. Bones & teeth
5. Muscle
6. Nervous system

Question 13

What cell is the most radiosensitive cell?

Answer 13

Lymphocytes!

they will always die first

Question 14

When are developing embryos most sensitive to radiation during mom’s pregnancy?

Answer 14

The first trimester, the earlier the worse it gets :(

Question 15

Describe the common hematopoietic effects of exposure to ionizing radiation

Answer 15

• Hypoplastic bone marrow (anemia)
• Leukopenia
• Thrombocytopenia
• Petechiae
• Recurrent infections (pneumonia/septicemia)
• Purpura

Question 16

Describe the common Intestinal effects of exposure to ionizing radiation

Answer 16

-Epithelial necrosis & ulceration
- High infection risk
- Acute diarrhea *dmg villa, then later constipation *due to scarring
- Septicemia

Question 17

Describe the morphological changes to tissues experiencing acute changes due to IR exposure

Answer 17

Vasculitis leading to fibrinoid necrosis

Question 18

Describe the morphological changes to tissues experiencing chronic changes due to IR exposure

Answer 18

Fibrosis