Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

ORAL RADIOLOGY EXAM 2 > radiation biology > Flashcards

radiation biology Flashcards

(86 cards)

Start Studying
1
Q

interactions of x radiation with matter

A

ionization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

radiation injury

A

a. direct vs indirect
b. dose response curves
c. deterministic vs stochastic risk
d. somatic vs genetic effects
e. sequence of radiation injury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

dose units for radiation measurement:
1. exposure dose
2. absorbed dose
3. equivalent dose
4. effective dose

A
  1. exposure dose: R vs. coulombs/kg
  2. absorbed dose: RAD vs. Gray (G)
  3. equivalent dose: REM vs. Sievert (Sv)
  4. effective dose: REM vs. Sievert (Sv)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

ionize air

A

exposure
traditional unit: R
SI unit: air kerma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

energy absorbed by tissue

A

absorbed dose
traditional unit: rad
SI unit: Gy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

modified by radiation weighting factor

A

equivalent dose
traditional unit: rem
SI unit: Sv

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

modified by tissue weight factor

A

traditional unit: rem
SI unit: Sv

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

measure of the capacity of radiation to ionize air

A

exposure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

exposure traditional unit

A

R roentgen

and air kerma in metric (kinetic energy released in matter)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

absorbed dose:

A

rad
radiation absorbed dose

100 radiation energy in 1 gram of absorbed material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

use to compare the biological effects of different types of radiation

A

equivalent dose (I)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

radiation weighing factor (Wr) depends on the type and energy:

A

of the radiation involved

Ht (equivalent dose)= Dt (absorbed dose) x Wr (radiation weighing factor)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

measure of the biological effectiveness of a radiation to ionize matter

A

equivalent dose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

the quality factor for x-radiation is

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

equivalent dose unit is REM that stands for

A

roentgen equivalent in man

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

equivalent dose is equivalent to

A

RAD x QF

(absorbed dose x Wr)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

since QF for x-radiation is 1, the RAD units for x-radiation are ____to REM units

A

equal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

effective dose calculation

A

E= SUM(Z) Wt x Ht
E= Z (tissue weight factor) x (dose equivalence to tissue)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

this measure is used to specifically calculate risks of radiation to human tissues on a common scale

A

effective dose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

product of the sum of dose equivalence to the specific tissues or organs exposed and the biological tissue weighting factor

A

effective dose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

**used to assess risk of non-uniform radiation to localized part of body and degree to which this would increase a person’s whole body risk of:

A

effective dose

  1. cancer induction and or
  2. induction of genetic mutations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

area exposed is related to the

A

maximum size of the beam

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

1 of 4 things can happen when you expose an object to x-radiation

A
  1. no interaction (pass right thru) 9%
  2. coherent scattering (heat and no ionize) 7%
  3. photoelectric absorption 27%
  4. compton scattering 57%
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

two ionizing effects are

A
  1. compton (incoherent) scatter
  2. photoelectric effect
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
mechanism of injury from xray interaction with matter (ionization)
radiation injury
26
ionization from ionizing radiation exposure sets off multiple direct and indirect molecular reactions in ____secs enzymatic repair or further deleterious molecular changes occur in deterministic and stochastic effects take place over time from
< 1 second in mins to hours months to decades to generations
27
x-ray photon enters object (patient or other tissues) and exits with no change in its energy
no interaction 9%
28
x-ray photon collides with an orbital electron and loses its energy. -ejected photoelectron loses its energy and results in an atom with an altered electric state ( example: + charge)
photoelectric interaction 30% of all interactions
29
in this interaction, the ionized matter is unstable and seeks a more stable configuration. the new configuration may include new ionic bonds, different covalent bonds, etc. if the degree of photoelectric effect is significant, this may affect:________ these effects are often deleterious biologic changes, like altered metabolic function or malignancy
photoelectric interaction AND compton interaction/scatter affect biologic structure, function or both
30
1. xray photon collides with an outer orbital electron losing some energy 2. xray photon continues in different direction with less energy creating more scatter until all the energy is lost 3. results in an atom with an altered eletric state (ex: + charge)
compton interaction/scatter 62% of interactions
31
1. xray photon of low energy interacts with an outer orbital electron and changes direction 2. no photoelectron produced 3. no ionization occurs
coherent interaction 8% of interactions
32
with direct and indirect radiation injury, both:
1. effects occur quickly 2. take hours to decades to become evident 3. result of ionization
33
this ionizes biologic maromolecules contributes to ~1/3 of biologic effects
direct effect
34
xray photons absorbed by H2O-> free radicals-> biologic damage contributes to ~2/3 of biologic effects
indirect effect
35
radiation strikes biologically active molecule= biologically active
direct effect
36
damaged molecule no longer capable of proper function= molecular death
radiation damage theory (bioloically active equals this)
37
3 outcomes of direct effect of UV light on skin DNA
1. repair (healed) 2. inaccurate repair (mutation) 3. no repair (death)
38
method of cell damage from radiolysis of water caused by x-radiation
primary indirect effect
39
indirect effect. photon + ____-> H2O-> OH+H
H2O
40
free atom or molecule carrying an unpaired orbital electron in the outer shell
free radical
41
free radical formation
xray photons interact with water in cells ionization occurs resulting in free radical formation
42
highly reactive and unstable lifetime=10^-10 seconds
free radical formation
43
free radicals seek a more stable configuration which results in formation of
toxic substances
44
(dose) amount of radiation is correlated with response or damage
dose-response curves
45
curves are ______for diagnositic xradiation
theoretical
46
threshold non-linear curve, small exposures to a substance (does/does not) produce measurable change
doesn't
47
what must be reached for exposure to produce measurable change
must meet threshold before changes are observed
48
most biologic effects are (linear/non-linear)
non-linear
49
dose is proportional to the response -no matter how small dose, there is some damage or risk
linear non-threshold curve
50
no threshold -minimal damage at first with increased rate of damage with increased dose
nonlinear nonthreshold curve
51
determinisitic risk/effect
1. have threshold 2. severity is proportional to the dose examples: erythema xerostomia'cataract fertility alopecia *fetal development
52
fetal effective dose
OMR imaging, 0.01mGy
53
threshold radiation erythema dose (TED)
250 rads
54
average radiation erythema dose
500 rads
55
maximum radiation erythema dose
750 rads
56
1. have no dose threshold 2. probability of occurrence is proportional to dose 3. severity of effects does not depend on dose
stochastic effect
57
genetic mutations cause malignancy (stochastic effect)
to somatic cells
58
genetic mutations cause heritable effects (stochastic effect)
to germ cells
59
radiation-induced cancer is not seen in doses _____10 mGy throughout pregnancy
<
60
no affect on parent, affects future generation
genetic injury
61
affects parent and no effect on future generatiion
somatic injury
62
all those except reproductive cells
somatic cells
63
seen in the person irradiate and NOT transmitted to future generations (induction of cancer, leukemia, cataracts)
somatic effects/mutations
64
not seen in person irradiated passed on to future generations
genetic effects/mutations
65
sequence of radiation injury
1. latent period 2. period of injury 3. recovery period
66
time that elapses between exposure and appearance of clinical signs
latent period
67
latent period can be short or long depending on
total dose and dose rate
68
shorter latent period if
1. increased amount of radiation 2. faster dose rate
69
genetic effects of latent period
may be generations before clinical effects are seen
70
* Cell death * Changes in cell function * Breaking or clumping of chromosomes * Giant cell formation * Cessation of mitotic activity * Abnormal mitotic activity
period of injury
71
* full recovery for a large percentage of individuals from a few weeks up to two years after exposure
recovery period
72
No recovery period i.e, death likey at higher does of >1.2 Gy (120 Rads).
>1.2 Gy (120 Rads).
73
factors modifying effects of x-radiation
1. Total dose 2. Dose rate 3. Oxygen 4. Area exposed 5. Cell type and function 6. Age
74
increase total dose:
increase damage
75
increase dose rate
decrease cellular repair which increases damages
76
increase oxygen content
increase radiosensitivity increase tissue damage
77
young, immature, rapidly growing and dividing, least specialized (what cell type)
radiosensitive
78
mature, specialized cells (what cell type)
radioresistant
79
____ more sensitive than reptiles, insects, bacteria
Mammals (species)
80
Mitotic activity increase frequency of cell division = ___sensitivity
increase sens
81
Mitotic activity Immature cells/not highly specialized = ___sensitivity
increase sens
82
Cell metabolism increase metabolism = ___sensitivity
increase sens
83
tissues/organs 1. high sens to radiation 2. least radioresistant
Blood cells Small lymphocyte – most sensitive Bone marrow Reproductive cells Intestinal mucosa Mucous membrane
84
tissues/organs Intermediate sensitivity to radiation
Connective tissue Breast (women) Small blood vessels Growing bone and cartilage Salivary gland
85
tissues and organs Fairly low sensitivity to radiation
Thyroid gland Skin
86
tissues/organs Low sensitivity to radiation Most radioresistant
Muscle Nerve Mature bone

ORAL RADIOLOGY EXAM 2 (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions