Radiation Biology Ch 6

Front 1

The branch of biology with effects of ionizing radiation on living systems.

Back 1

Radiation Biology

Front 2

Ineraction of radiation in cells is a matter of what?

Back 2

chance

Front 3

Can damage by radiation be repaired?

Back 3

yes

Front 4

Radiation deposits energy in a cell in a _________ fashion.

Back 4

random

Front 5

Is radiation damage any different than normal trauma?

Back 5

no

Front 6

Do biologic changes appear immediately?

Back 6

no

Front 7

What does the length of latency depend on?

Back 7

dose given, as well as to biological characteristics of the irradiated.

Front 8

What 3 concepts determine severity of injury?

Back 8

1. Linear Energy Transfer

2. Relative Biologic Effectiveness

3. Oxygen Enhancement Ratio

Front 9

What has a low let?

Back 9

external electromagnetic radiations such as x-rays and gamma rays

Front 10

What has a high let?

Back 10

particles that possess substantial mass and charge such as alpha particles.

Front 11

A large QF= what?

Back 11

large rbe

Front 12

What is the oxygen enhancement ratio?

Back 12

Radiation is more damaging to tissue in an aerobic state.

Front 13

When ionizing radiation interacts with a cell, ionizations and excitations are produced where?

Back 13

targets(dna) or medium which organelles are suspended(water)

Front 14

Radiation damage is seen on what 3 levels?

Back 14

molecular, cellular, and organic

Front 15

Any visible radiation induced injuries always begin with damage at what level?

Back 15

molecular

Front 16

with somatic cell involvement what can be disrupted?

Back 16

entire body

Front 17

When germ cells are damaged what are the affects?

Back 17

genetic mutations of future generations

Front 18

What is direct action?

Back 18

when photon hits DNA

Front 19

What is indirect action?

Back 19

photon hits H2O, causes chemical reaction that is toxic to DNA

Front 20

Are the effects of direct action and indirect action the same?

Back 20

yes

Front 21

What percentage is indirect action?

Back 21

95%

Front 22

Break in backbone of one chain of DNA- repairable

Back 22

Single Strand Break

Front 23

widely spaced , may repair with difficulty or may result in cell death?

Back 23

Double Strand break

Front 24

causes irrepairable damage or cell death

Back 24

Double strand break on same rung

Front 25

change or loss of a base casues mutation which cell divisions result in daughter cells with incorrect genetic information.

Back 25

Nitrogenous Base damage

Front 26

Effects of ionizing radiation on chromosomes deals with primarily what type of x-ray modality?

Back 26

radiation therapy

Front 27

If radiation damage is severe what may be detected?

Back 27

visible chromosome aberrations

Front 28

What are the effects of ionizing radiation on chromosomes? and explain them.

Back 28

1. Terminal delection
2. Dicentric formation
3. ring formation4.
4. radiation induced reicprocal translocations.

Front 29

States that there are targets in a cell, all of which must be "hit" to kill the cell. If one target is not hit, the cell will survive and repair the damage. As dose increases, the more damage accumulates and the cell dies.

Back 29

Target theory

Front 30

What are the main concepts of target theory?

Back 30

there is a key molecule that is deactivated
can happen with direct or indirect hit
when oxygen is present, more probability of a hit

Front 31

What are the two factors dealing with the law of bergonie and tribondeau?

Back 31

1. x-rays appeared to destroy the cells of a malignant tumor without permanently damaging the healthy tissue.
2.Some tissues were damaged by doses that did not appear to harm other tissues.

Front 32

What hypothesis did Bergonie and Tribondeau come up with?

Back 32

1. The stem cells are radiosensitive
2. Younger tissues are more sensitive
3. When metabolic activity is high, radiosensitivity is high
4. As proliferation rate increases, radiosensitivity increases. embryo-fetus most sensitive
5. Undifferentiated cells are more sensitive.

Front 33

what cells are highly radiosensitive?

Back 33

lymphocytes, spermatogonia, erythroblast, intestinal crypt cells

Front 34

What type of cells have intermediate radiosensitivity?

Back 34

endothelial, osteoblasts, spermatids, fibroblasts

Front 35

What ype of cells have low radiosensitivity?

Back 35

muscle, nerve

Front 36

responses such leukemia cancer and genetic effects referred to as stochastic.

Back 36

Linear non threshold

Front 37

certain dose will show an effect such as skin erythema referred to as nonstochastic.

Back 37

Linear non threshold

Front 38

Factors on which amount of somatic and genetic damage depends.

Back 38

1. Quantity of ionizing radiation(mas)
2. Ability to cause ionization(QF)
3. Amount of body exposed(collimation)
4. Specific parts exposed(shielding)

Front 39

Before radiation monitors how was exposure measured?

Back 39

blood test

Front 40

In humans, a response to radiation that occurs within months from the time of exposure is called an _______ __________.

Back 40

Early Effect

Front 41

Effects that become more severe with increased radiation dose are __________ and there is usually a close _________.

Back 41

deterministic, threshold