quiz 2 - radiation biology

Question 1

Which one of these is least susceptible to radiation?

Answer 1

Low sensitivity: neurons, muscle, MATURE BONE

high sensitivity: BLOOD CELLS lymphoid organs, BONE MARROW, testes, intestines, mucosal lining.

Question 2

Types of scattered radiation:

Answer 2

Unmodified (coherent) scattering. not enough energy to ionize. 7%.
Compton (incoherent) scattering. 57%. dangerous one, due to ionizing.

Question 3

Unmodified (coherent) scattering.

Answer 3

hits inner shell electron, changes direction.

Question 4

Compton (incoherent) scattering.

Answer 4

x ray photon comes in , knocks out outer shell electron. Compton electron ejected. No longer balanced because we hit out an electron, thus this causes ionization. Big biologic risk.

Question 5

X-ray beam absorption:

(photoelectric absorption)

Answer 5

x ray photon comes in, knocks out inner shell electron. This takes a lot of x-ray photon energy and stops it. Ionization occurs again but stops x-ray photon. image is blocked. useful because it contributes to image

always photoelectric absorption
27% occurrence.

Question 6

exposure dose:
absorbed dose:
equivalent dose:
effective dose:

Answer 6

exposure dose: x-ray output
absorbed dose: how much energy absorbed in a certain amount of area.
equivalent dose: type of radiation. it is the absorbed dose x weighing factor. weighing factors: just know that x-rays are not as dangerous as other things like high energy protons and alpha particles.
effective dose: equivalent dose x tissue weight factor.

Question 7

radiation injury:
direct vs indirect

Answer 7

direct: directly ionizes. 1/3 time
indirect: highly reactive, can hit water and make other things.

Question 8

somatic vs genetic effects of radiation

Answer 8

1.) give high dose radiation to dog. then these two occur:

genetic mutation: offspring of dog is bad
somatic mutation: dog itself went bad

Question 9

3 dose-response curves, which one is real, then which one does government use?

Answer 9

Linear non-threshold curve
threshold non-linear curve: this is what typically happens
nonlinear nonthreshold curve: gov uses this one.

Question 10

Radiation injury:
deterministic vs stochastic.

Answer 10

non-stochastic (deterministic): have a threshold. “if i give you this much does, you will get a skin burn”
stochastic: think of playing the lottery. think of outcome is cancer. one x ray can give you cancer, but a million x rays also can give no cancer.

Question 11

radiation injury:
sequence:

latent period, period of injury, recovery period.

question on this.

Answer 11

depending on how much dose you get and the amount of time that you get it in has a big effect on how this timeline happens.

once you get exposed, there is a latency period before you start to see outcomes. On kids, they live longer, so there’s a longer chance they will see effects so u want very low dose on kids.

Latent period: depends on TOTAL DOSE and AMOUNT OF TIME it took to receive dose.

Period of injury: skin burn.
Recovery period: body repairing things

Question 12

increased oxygen ->

Answer 12

increased ur reaction to radiation.

Question 13

Law of Bergonie and Tribondeau

Answer 13

we are more radiosensitive when we are young. we have more immature type cells, rapidly growing cells. have least specialized cells.

radioresistance - mature, specialized cells.