exam 2 review: module 3

cellular response to radiation that involves the cells stalling in G2

division delay (mitotic delay)

what is it called when the cell overcomes the division delay and all the cells move into mitosis at once

mitotic overshoot

cellular response to radiation that involves the cells stalling in G2

division delay (mitotic delay)

what is it called when the cell overcomes the division delay and all the cells move into mitosis at once

mitotic overshoot

this is when the cells die before reaching mitosis

interphase death (Nonmitotic or Nondivision Death)

what is the most common cellular response to radiation; when the cells die during mitosis

reproductive failure (mitotic death)

programmed cell death

aptosis

on a cell survival curve, the horizontal (x) axis represents:

dose

parameter of the target model that is also referred to as the “target number” or the “extrapolation number”

n

mammalian cells have a “n” number of

2-10

if the “n” number is small the cell is more

radiosensitive

which parameter of the multitarget theory represents the width of the cell survival curve’s shoulder

D_q

T/F the wider the shoulder on the multitarget theory the better the cell can survive from sublethal damage

true

T/F a narrow shoulder on a cell survival curve indicates that the cell is radiosensitive

true

what does the shoulder of a high-LET look like on the multitarget theory

there isn’t one

what does D₀ or D₃₇ of the multitarget theory indicate

dose at which only 37% of cells survive

Represents the final slope of the survival curve (linear portion)

D₃₇

cells with a low D₃₇ indicate that they are

radiosensitive

on a linear quadratic model, which parameter represents the accumulation of sublethal dose kills

beta

linear component of the linear quadratic model

alpha

The dose at which the linear (αD) and quadratic (βD²) components are equal.

alpha/beta ratio

single event killing of the linear quadratic model

alpha

multiple hit event killing of the linear quadratic model

beta

early responding tissues or acutely responding tissues have a large alpha/beta ratio (large alpha to the beta)

true

would fractionation be good for acutely responding tissues with a high alpha/beta ratio

no (it doesn’t matter because they can’t repair)

would fractionation be good for late-responding tissues with a low alpha/beta ratio

yes

what kind of alpha/beta ratio do tumors have

high

Acutely Responding Tissues graph is more (LQ Model)

linear

Late-Responding Tissues graph is more (LQ Model)

curved

Nonlethal and can be repaired or accumulated if further radiation is received is considered (doses separated by time)

sublethal

Damage that can be repaired before the next mitosis if conditions allow is considered (environment comes into play)

potentially lethal damage

the key factor of potentially lethal damage

environment

LET has a ____ relationship with radiation damage

direct

RBE has a ____ relationship with radiation damage

direct

dose rate has a ____ relationship with radiation damage

direct

fractionation has a ____ relationship with radiation damage

inverse

T/F number of fractions is apart of the BED formula

true

T/F dose per fraction is apart of the BED formula

true

T/F alpha/beta ratio is apart of the BED formula

true

T/F target number is apart of the BED formula

false

Accounts for the effects of fractionation; Considers differing behaviors of acutely and late-responding tissues (applies alpha/beta ratios)

biologically effective dose (BED)

Most potent radiosensitizer

oxygen

oxygen as a radiosensitizer is most effective when given simultaneously with ______

radiation

Oxygen as a radiosensitizer enhances

free radicals

oxygen as a radiosensitizer has impact with ___-LET radiation

low

Numeric representation of the dose comparison for a given biological effect under anoxic and aerobic conditions

oxygen enhancement ratio (OER)

OER for mammalian cells:

2.5-3

Be familiar with fractionation schedule