Lec 3 Classification of Biologic Effects

Question 1

2 types of biologic effects

Answer 1

Stochastic Effect
Deterministic Effect

Question 2

Stochastic effect or deterministic effect?

No threshold dose

Answer 2

Stochastic effect

Question 3

Stochastic effect or deterministic effect?

Cell killing

Answer 3

Deterministic Effect

Question 4

Stochastic effect or deterministic effect?

Sublethal DNA damage

Answer 4

Stochastic effect

Question 5

Stochastic effect or deterministic effect?

Caused by doses used in diagnostic radiology.

Answer 5

Stochastic effect

Question 6

TRUE OR FALSE

A single x-ray photon has the potential to cause a DNA mutation

Answer 6

TRUE

Question 7

TRUE OR FALSE

Even the smallest radiation dose could cause a heritable effect or cancer.

Answer 7

TRUE

Question 8

Stochastic effect or deterministic effect?

Manifest only when the radiation exposure to an organ or tissue exceeds a threshold level.

Answer 8

Deterministic Effect

Question 9

Stochastic effect or deterministic effect?

The higher the dose, the more severe the effect.

Answer 9

Deterministic Effect

Question 10

Stochastic effect or deterministic effect?

Severity of clinical effects is independent of dose; all-or-none response an individual either manifests effect or does not.

Answer 10

Stochastic effect

Question 11

TRUE OR FALSE

Dental radiography has low to no deterministic effect.

Answer 11

TRUE

Question 12

TRUE OR FALSE

Deterministic effect are tissue reactions.

Answer 12

TRUE

Question 13

TRUE OR FALSE

Stochastic effect are caused by cell killing.

Answer 13

FALSE

Question 14

TRUE OR FALSE

Deterministic effect manifest only when the radiation exposure exceeds a THRESHOLD level.

Answer 14

TRUE

Question 15

2 subdivisions of Stochastic effect?

Answer 15

• Radiation-induced cancer
• Heritable effects

Question 16

2 types of cell killing?

Answer 16

• Mitotic death
• Apoptosis

Question 17

TRUE OR FALSE

Radiation-induced cancers are clinically and histologically the same from sporadically occurring or chemical-induced cancers.

Answer 17

FALSE

Radiation-induced cancers are clinically and histologically INDISTINGUISHABLE from sporadically occurring or chemical-induced cancers.

Question 18

Examples of tissues / organs that are more sensitive to carcinogenic effects of ionizing radiation.

Answer 18

• Female breast
• Thyroid gland

Question 19

TRUE OR FALSE

There is a long latent period, ranging from years to decades, between radiation exposure and the occurrence of cancer.

Answer 19

TRUE

Question 20

TRUE OR FALSE

The risk of radiation-induced tumor induction is approximately threefold higher in children than in adults.

Answer 20

TRUE

Question 21

Examples of radiation-induced cancers.

Answer 21

• Leukemia
• Thyroid cancer
• Salivary gland tumors (Warthin tumor)
• Breast cancer
• Brain and nervous system cancers

Question 22

Changes seen in the offspring of irradiated individuals.

Answer 22

Heritable effects

Question 23

Consequence of DNA damage in germ cells.

Answer 23

Heritable effects

Question 24

TRUE OR FALSE

Studies of the children of patients who received radiotherapy show NO detectable increase in the frequency of genetic diseases

Answer 24

TRUE

Question 25

Most common means of cell killing.

Answer 25

Mitotic death

Question 26

Mitotic death is explained by the law of?

Answer 26

The Law of Bergonié and Tribondeau

Question 27

Cell radiosensitivity to killing = ________ / _________

Answer 27

Mitotic rate / Degree of differentiation

Question 28

Rapidly dividing cells will be more ____________ and postmitotic specialized cells will be most __________.

Answer 28

- radiosensitive - radioresistant

Question 29

Programmed cell death.

Answer 29

Apoptosis

Question 30

__________ are an exception to Bergonié and Tribondeau's law.

Answer 30

Lymphocytes

Question 31

The most radiosensitive mammalian cell.

Answer 31

Lymphocytes

Question 32

__________ of the salivary glands are highly radiosensitive.

Answer 32

Serous acini

Question 33

TRUE OR FALSE Embryos and fetuses are more radiosentitive than adults.

Answer 33

TRUE

Question 34

The deterministic effects on embryos and fetuses depends on _______ and _______ during irradiation.

Answer 34

- dose - gestational age

Question 35

Irradiation during preimplantation (0 to 9 days in humans) causes ___________. The threshold for this effect is estimated to be __________. In comparison, the dose to an embryo and fetus from natural background radiation is approximately __________ during the 9 months of gestation. Fetal irradiation is associated with __________ (irradiation at 8 to 15 weeks gestation) and _____________ (irradiated at 8 to 25 weeks' gestation).

Answer 35

- embryonic death - 100 mGy - 0.5 to 1 mSv - microcephaly; mental retardation