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Chapter 7 Flashcards

1
Q

Potentially harmful effects of ionizing radiation on living systems occur primarily at what level

A

Cellular

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2
Q

Biologic damage occurs from what types of radiation

A

Xrays
Gamma Rays
Alpha particles
Beta particles
Protons

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3
Q

What differs among various types of radiation

A

Charge, mass, and energy

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4
Q

What attributes determine the extent to which different radiation modalities transfer energy into biologic tissue

A

Charge, mass, and energy

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5
Q

What are the three concepts to understand how ionizing radiation causes injury to biologic tissue

A

Linear Energy Transfer
Relative Biologic Effectiveness
Oxygen Enhancement Ratio

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6
Q

The average energy deposited per unit length of track by ionizing radiation as it passes through and interacts with a medium along its path

A

LET

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7
Q

How is LET measured

A

keV/um

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8
Q

What are the 2 radiation categories of LET

A

Low-linear energy transfer
High-linear energy transfer

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9
Q

What type of radiation has a low-LET

A

Gamma rays
X-rays

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10
Q

What type of radiation has a high-LET

A

Alpha particles
Ions of heavy nuclei
Charged particles released from interactions between neutrons and atoms
Low-energy neutrons

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11
Q

Describes the comparative capabilities of radiation with differing LETs to produce a particular biologic reaction

A

Relative Biologic Effectiveness

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12
Q

What is the ratio to determine RBE

A

Dose (in Gy) of reference radiation to Dose (in Gy) of test radiation

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13
Q

What is typically used as the reference radiation to determine RBE

A

250 kVp x-rays

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14
Q

What is the Oxygen Enhancement Ratio

A

Radiation dose required to cause biologic damange without oxygen to Radiation dose required to cause biologic damage with oxygen

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15
Q

What is the OER for x-rays and gamma rays

A

3

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16
Q

Biologic damage resulting from exposure to ionizing radiation can be observed on what 3 levels

A

Molecular
Cellular
Organic systems

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17
Q

Any visible radiation-induced injuries of living systems at the cellular or organic level always begin with damage at what level

A

Molecular

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18
Q

If a sufficient quantity of _______ cells are affected by ionizing radiation, entire body processes may be disrupted

A

Somatic

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19
Q

If radiation damages _____ cells, the damage may be passed on to future generations

A

Germ cells

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20
Q

What are the two classifications of ionizing radiation interactions on a cell

A

Direct action
Indirect action

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21
Q

Essentially all effects of irradiation in living cells result from _______ action

22
Q

Ionization of water molecules

A

Radiolysis

23
Q

Effects of radiolysis

A

Production of free radicals
Production of unstable chemical reactions and biologic damage
Production of cell-damaging substances

24
Q

Ionizing radiation interacts with DNA macromolecule, transfers energy, and ruptures one of the molecule’s chemical bonds

A

Single-strand break

25
Ionizing radiation interacts with DNA macromolecule, transfers energy, and ruptures additional breaks of the molecule's chemical bonds
Double-strand break
26
Double-strand breaks occur more commonly with densely ionizing _____-LET radiation
High
27
Result is a cleaved or broken chromosome with each new portion containting an unequal amount of genetic material
Double-strand break
28
Alteration of the base sequence caused by ionizing radiation interacting with a DNA molecule
Mutation
29
Mutation is a/an ______ consequence (indirect/direct)
Direct
30
Chemical unions created between atoms by the single sharing of one or more pairs of electrons
Covalent cross-links
31
Covalent cross-links are initiated by ____ -LET radiation
High
32
Types of cross-link patterns
Intrastrand Interstrand
33
Types of radiation-induced chromosome breaks in both somatic and reproductive cells
Chromosomal fragments Chromosomal anomalies -chromosome aberrations -chromatid aberrations Structural changes
34
Consequences to the cell from structural changes in biologic tissue
Restitution Deletion
35
The chromosome break rejoins in the original configuration with no visible damage
Restitution
36
Part of a chromosome is lost at the next cell division, creating an acentric fragment
Deletion
37
Theory that there is a master, or key, molecule that maintains normal cell function is present in every cell
Target Theory
38
Damage to the cell's nucleus reveals itself in what ways
Reproductive death Apoptosis (interphase death) Mitotic (genetic) death Mitotic delay Interference w/ function
39
What does the cell survival curve display
Sensitivity of a particular type of cell to radiation
40
Radiosensitive cells
Basal cells Blood cells Intestinal crypt cells Reproductive (germ) cells
41
Radioinsensitive cells
Brain cells Muscle cells Nerve cells
42
______ enhances the effects of ionizing radition on biologic tissue by increasing tissue radiosensitivity
Oxygen
43
Law of Bergoine and Tribondeau established that radiosensitvity was a function of the _________ state of the cell receiving the exposure
Metabolic
44
Law of Bergoine and Tribondeau states that the radiosensitivity of cells is _______ proportional to their reproductive activity and _______ proportional to their degree of differentiation
Directly Indirectly
45
Law of Bergoine and Tribondeau observed the effects of ionizing radiation on ____________ cells of rabbits that had been exposed to x-rays
Testicular germ cells
46
The most pronounced radiation effects occur in cells having the _______ maturity and specialization or differentiation, the _____reproductive activity, and the _______ mitotic phase
Least Greatest Longest
47
Equation for linear energy transfer
Total energy/total length of track
48
What is x-rays LET
3 keV/um
49
What is the result of the interaction of radiation with water
Formation of an ion pair H+ and OH- and 2 free radicals H and OH
50
Chromatid break rejoins in the original configuration with no visible damage
Restitution
51
Chromosome is lost at the next cell divison, creating an acentric fragment
Deletion
52
The cell will die after exposure to ionizing radiation if the master, or key molecule (DNA) is inactivated in the process
Target Theory

Rad Bio (14 decks)

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