chapters 30, 31, 33, 34

Question 1

radiobiology

Answer 1

ionizing radiation effects on biological systems

Question 2

deterministic effects

• 3 characteristics
• ex

Answer 2

• higher doses over shorter times
• severity varies with dose
• usually a threshold
• acute radiation syndrome

Question 3

stochastic effect

• 3 characteristics
• ex

Answer 3

• lower doses over longer times
• probability of disease varies with dose
• assume no threshold
• cancer, cataracts

Question 4

acute radiation syndrome

• shows up
• 2 phases

Answer 4

• 1-2 months

- prodromal and latent

Question 5

prodromal phase

Answer 5

characterized by nausea, vomiting and diarrhea

Question 6

LET

-what does it stand for

Answer 6

amount of energy deposited per path length

-energy/length

Question 7

high LET

• type
• equation

Answer 7

• alpha

- high energy/short path

Question 8

low LET

• type
• equation

Answer 8

• beta

- lower energy/longer path

Question 9

RBE

• what does it stand for
• definition

Answer 9

• relative biological effectiveness

- dose to produce some effect/dose of 250 kVp x-rays to get same effect

Question 10

Laws of Bergonie and Tribondeau

Answer 10

1. stem cells are radiosensitive, mature cells are not as much
2. younger tissues and organs are more radiosensitive
3. tissues with high metabolic rates are more radiosensitive
4. cells that divide frequently and tissues that are rapidly growing are more radiosensitive

Question 11

biological factors affecting radiosensitivity

Answer 11

1. oxygen effect - lack of O2 makes cells radio resistant
2. age
3. cells can repair radiation damage
4. chemical agents can effect radiosensitivity
5. hormesis: some evidence that small levels of radiation can enhance survivability

Question 12

DNA damage results

Answer 12

1. cell death at next division
2. malignant diseases
3. genetic damage

Question 13

direct damage

Answer 13

radiation particles

Question 14

indirect damage

Answer 14

free radicals