Radiation Exposure & Effects

Question 1

identify the quantity
The fundamental dosimetric quantity for ionizing radiation; The energy ionizing radiation imparts to matter per unit mass

Answer 1

absorbed dose

Question 2

identify the quantity
Biological effect caused by ionizing radiation and whose probability of occurrence is zero at small absorbed doses but will increase steeply to unity (100%) above some level of absorbed dose (the threshold)

Answer 2

deterministic biological effect

Question 3

identify the quantity
The absorbed dose averaged over a tissue or organ (rather than at a point) and weighted for the radiation quality that is of interest

Answer 3

equivalent dose

Question 4

identify the quantity

The sum of the weighted equivalent doses in all the tissues and organs of the body.

Answer 4

effective dose

Question 5

identify the quantity
Expresses the relative amount of damage that a fixed amount of ionizing radiation of a given type can inflict on biological tissues.

Answer 5

relative biological effect

Question 6

identify the quantity
Biological effect caused by ionizing radiation whose probability of occurrence increases with increasing absorbed dose, probably with no threshold, but whose severity is independent of absorbed dose.

Answer 6

stochastic biological effect

Question 7

Which is false?
A. Higher RBE value=more damaging
B. For deterministic biological effect, there’s a threshold
C. Equivalent dose & effective dose have diff. units

Answer 7

C - parehong Sievert ang kanilang unit

Question 8

Which is false?
A. When exposure surpass the threshold, somehow direct relationship: ↑dose exposed to, ↑DBE
B. Effective dose’s special unit name: Gray
C. Use of equivalent dose is not appropriate for large absorbed doses delivered in a relatively short period of time

Answer 8

B is false. unit for effective dose is Sievert.

C is true because Equivalent dose: radiation safety qty

Question 9

identify the quantity
Represents the contribution of tissue or organ T to the total detriment due to all of the stochastic effects resulting from uniform irradiation of the whole body.

Answer 9

tissue weighing factor

Question 10

Which is false?
A. The RBE may not be a continuous number
B. The probability of stochastic effects due to an equivalent dose depends on the tissue or organ irradiated.
C. The sum of all tissue weighting factors is equal to 1

Answer 10

A - it may be a decimal number

Question 11

Which is false?
A. When exposure surpasses the threshold, higher dose of radiation means higher DBE.
B. Higher tissue weighting factor @ organs without actively dividing cells
C. BOTA
D. NOTA

Answer 11

B - higher TWF @ those with actively div cells

Question 12

Radiation effect of energy deposition: Explain how it affects the body

Answer 12

Ionizing radiation is capable of depositing enough localized energy to dislodge electrons from the atoms with which it interacts –> ions and free radicals which break chemical bongs –> CELLULAR INJURY

Question 13

Most radiation-caused DNA lesions are reparable, but less reparable are those produced by:
A. densely ionizing radiation
B. proton
C. alpha particle
D. NOTA

Answer 13

(D)

Question 14

Which is false?
A. Traversal of the DNA by a single ionizing particle is not enough to cause a mutation
B. The dose-response relationship for chromosome aberrations in human blood lymphocytes can serve as a useful biological dosimeter
C. Dividing cells are radiosensitive
D. The survival of dividing cells tend to decrease exponentially with increasing dose, 1 to 2 Gy –> reduce the surviving population by 50%

Answer 14

A - it’s enough

Question 15

Which is false?
A. Rate of atrophy is dependent on cell population dynamics within the affected tissue of surviving cells
B. Rate of atrophy is directly proportional to rate of cell division
C. Mature cells are relatively more radiosensitive compared to young dividing cells.

Answer 15

C - less dapat

Question 16

Enumerate two types of biological effects of radiation

Answer 16

heritable effects

somatic effects

Question 17

differentiate stochastic from non-stochastic effect

Answer 17

NON-stochastic or deterministic: result from depletion of progenitor cells in affected tissues and can be elicited only by doses that are large enough to kill many such cells; (+) threshold

Stochastic: in contradistinction to the mutagenic and carcinogenic effects of radiation; (-) threshold

Question 18

identify effect of radiation on skin (6 Sv)

Answer 18

Erythema —> Epilation

Question 19

identify effect of radiation on skin (10-20 Sv)

Answer 19

Blistering, Ulceration, Necrosis –> Fibrosis –> Atrophy

Question 20

identify effect of radiation on bone marrow (2-3 Sv, within hours)

Answer 20

impaired immune response

Question 21

identify effect of radiation on skin (2-3 Sv, 3-5 wks)

Answer 21

granulocytopenia & thrombocytopenia

Question 22

identify effect of radiation on intestines (10 Sv)

Answer 22

denuded intestinal villi –> dysentery-like syndrome

Question 23

identify effect of radiation on testes (0.15 Sv)

Answer 23

oligospermia

Question 24

identify effect of radiation on testes (2-4 Sv) & oocytes (1.5-2.0 Sv)

Answer 24

permanent sterility

Question 25

identify effect of radiation on respiratory tract (6-10 Sv)

Answer 25

acute pneumonitis

Question 26

identify effect of radiation on eyes (> 1 Sv)

Answer 26

microscopic posterior polar opacity

Question 27

one of the effects of radiation on the eyes is vision-impairing cataract. how can this happen? what are the doses/timeframes

Answer 27

2 - 3 Sv in a single brief exposure
OR
5.5 - 14 Sv accumulated over a period of months

Question 28

What is acute radiation syndrome?

Answer 28

results from rapid exposure of a major part of the body to a dose in excess of 1 Gy

Question 29

4 organ systems affected @ acute radiation syndrome. enumerate

Answer 29

1. hematological
2. gastro-intestinal
3. cerebral
4. pulmonary

Question 30

first day after irradiation: two most common forms/features of acute radiation syndrome

Answer 30

nausea

vomiting

Question 31

Which is false?
A. Radionuclides tend to be distributed systematically & to irradiate the body as a whole
B. Radioactive iodine concentrates in the pineal gland
C. Strontium-90 primarily injures skeletal tissues

Answer 31

B - thyroid gland dapat

Question 32

Carcinogenic effects’ induction - which is false?
A. has been detectable only after relatively small dose equivalents (0.1 Sv)
B. varied with the type of neoplasm
C. varies with the age and sex of those exposed

Answer 32

A – relatively big dose equivalents dapat (0.5 Sv)

Question 33

Enumerate two main mechanisms of carcinogenic effects of radiation

Answer 33

activation of oncogene

inactivation/loss of tumor-suppressor

Question 34

oncogene activation can induce carcinogenic effect of radiation. how?

Answer 34

Oncogenes - genes having the potential to cause a normal cell to become cancerous; accelerate cell growth and division

Question 35

Which is false?
A. Effects of radiation are only additive/synergistic with chemical carcinogens
B. Existing data is not enough to justify dose-incidence relationship
C. Heritable effects of radiation are not observed in humans

Answer 35

A - they may also be antagonistic :)

Question 36

False about prenatal irradiation
A.susceptibility to malformation is high all throughout the prenatal period
B.effects of a given dose is the same across all developmental stages
C.there’s dose-dependent increase in the frequency of severe mental retardation

Answer 36

B - effects of a gien dose depend on the developmental stage of embryo/fetus