Ch 30 Fundamental Principles of Radiobiology

Question 1

What are the different names for Stem Cells?

Answer 1

• Immature Cells
• Precursor
• Undifferentiated Cells

Question 2

What type of cells are sensitive to Radiation?

Answer 2

Immature cells

Question 3

What does proliferation mean?

Answer 3

The splitting/ dividing of cells

Question 4

What happens to cells the more mature they are?

Answer 4

They become more resistant to radiation

Question 5

What is the law needed to understand the biologic effects of radiation?

Answer 5

The Law of Bergonie and Tribondeau

Question 6

What are the Laws of Bergonie and Tribondeu?

Answer 6

• Stem cells are radiosensitive, the more mature a cell, the more resistant to radiation
• The younger the tissue, the more radiosensitive
• When metabolic activity is high, radio sensitivity is high
• As proliferation increases, so does radio sensitivity

Question 7

What is the radiosensitvity of cells proportional to?

Answer 7

Their reproductive activity

Question 8

The radio sensitivity is inversely proportional to:

Answer 8

Their degree of differentiation

Question 9

When does the most pronounced radiation effects in cells occur?

Answer 9

When they have the least maturity and specialization or differentiation

Question 10

What law mainly has application in Radiation Therapy?

Answer 10

The law of Bergoine and Tribondeau

Question 11

What type of cell is more sensitive to radiation, immature or mature cells?

Answer 11

Immature cells

Question 12

What does LET stand for?

Answer 12

Linear Energy Transfer

Question 13

What does RBE stand for?

Answer 13

Relative Biologic Effectiveness

Question 14

What does OER stand for?

Answer 14

Oxygen Enhancement Ratio

Question 15

What are the (3) attributes that determine the extent to which radiation energy is transferred into biologic tissue?

Answer 15

LET
RBE
OER

Question 16

What is the rate radiation energy is transferred into soft tissue in diagnostic x-rays?

Answer 16

3 keV

Question 17

What is an important factor in assessing potential tissue and organ damage from exposure to ionizing radiation?

Answer 17

LET

Question 18

What two categories, can LET be divided into?

Answer 18

High and Low

Question 19

What attribute is a method of expressing radiation quality?

Answer 19

LET

Question 20

What are examples of Low- LET radiation?

Answer 20

External Electromagnetic Radiations

  - X-rays
  - Gamma rays

Question 21

Does low LET relinquish their energy quickly or over a sustained amount of time?

Answer 21

Over time

Question 22

How does low LET cause damage?

Answer 22

Primarily through indirect action; involves free radicals

Question 23

What does High LET radiation include?

Answer 23

Particles that possess substantial mass and charge.

Question 24

What are some examples of High LET radiation?

Answer 24

• Alpha particles
• Ions of heavier nuclei
• Beta radiation

Question 25

How well does High LET radiation penetrate?

Answer 25

Not very well, | It gives up energy quickly

Question 26

What type of LET causes the most damage?

Answer 26

High

Question 27

What increases as LET increases?

Answer 27

The ability of ionizing radiation to produce a biologic response

Question 28

Does beta radiation have more energy than x-rays?

Answer 28

No, beta particles just lose their energy into the tissue faster

Question 29

What escalates as the LET of radiation increases?

Answer 29

Biologic damage produced by radiation

Question 30

What are some Biologic Factors that Affect Radiosensitivity?

Answer 30

- Oxygen effect (OER) - Age (consistent with the law of B&T) - Recovery - Chemical agents - Hormesis

Question 31

What does Hormesis mean?

Answer 31

A little bit of radiation is good for you

Question 32

What is OER?

Answer 32

- Oxygen Enhancement Ratio - The ratio of the radiation dose required to cause a particular biologic response of cells in an oxygen deprived environment

Question 33

What is more sensitive to radiation, a fetus or a newborn?

Answer 33

A fetus

Question 34

Who is more sensitive to radiation, a newborn or a young child?

Answer 34

A newborn

Question 35

What happens to radiosensitivity in teens?

Answer 35

It decreases

Question 36

At what age specifically in teens does radiosensitivity decrease the most?

Answer 36

18 y/o

Question 37

Radiosensitivity stabilizes as we age. At what age does it begin to increase again?

Answer 37

70 y/o

Question 38

When are breast cancer rates increased?

Answer 38

When children are exposed to radiation at a time when breast tissue is developing

Question 39

What are growing children 2-3 times more radiosensitive than adults in developing?

Answer 39

Leukemia

Question 40

What does Dose Protraction mean?

Answer 40

Continuous dose of radiation at a lower rate, Bigger dose in a smaller amount of time

Question 41

Define Dose Fractionation:

Answer 41

Divided doses of radiation given at a low rate, more of a treatment plan over time

Question 42

Define Nonthreshold:

Answer 42

Small dose could cause an effect

Question 43

Define Threshold:

Answer 43

Level is reached below, which no effects are observed

Question 44

Curves are either:

Answer 44

Linear or non linear

Question 45

As dose increases:

Answer 45

So do the effects

Question 46

What is another name for Deterministic radiation responses?

Answer 46

Nonstochastic

Question 47

What is a Hematologic disorder?

Answer 47

Blood

Question 48

What does Epilation mean?

Answer 48

Loss of hair

Question 49

What does Erythema mean?

Answer 49

Redness of skin

Question 50

What does Desquamation mean?

Answer 50

Shedding of outer layer of skin

Question 51

Following a high dose exposure to radiation that appeared within minutes, hours, days or weeks after exposure would be an example of:

Answer 51

Deterministic/ Nonstochastic

Question 52

What are some examples of Deterministic/ Nonstochastic effects?

Answer 52

- Cytogenetic damages - Hematologic depression - Skin damage * Epilation * Desquamation * Erythema

Question 53

What is another name for a Stochastic response?

Answer 53

Probabilistic

Question 54

What is the name for responses that appear years later:

Answer 54

Stochastic/ Probabilistic

Question 55

What are some examples of Stochastic/ Probabilistic responses?

Answer 55

- Cancers - Leukemia - Genetic Disorders