6.2 Biologic Effects of Radiation

Question 1

Approximately ___ of all deaths are caused by
cancer; therefore, any radiation-induced cancers
are obscured.

Answer 1

20%

Question 2

Thyroid Cancer as a effect of radiation was first manifested by

Answer 2

• Ann Arbor series and the Rochester series

- Rongelap Atoll natives

Question 3

Consisted of individuals who were treated

shortly after birth for thymic enlargement

Answer 3

Ann Arbor series and the Rochester series

Question 4

The thymus gland was irradiated with doses up
to ____ and would shrink so small the
enlargement would disappear

Answer 4

5 Gyt (500 rad)

Question 5

No additional problems were evident until _____ later, when thyroid nodules and thyroid
cancer began to develop in some of these
patients

Answer 5

20 years

Question 6

21 children were subjected to high levels of radiation

fallout during a hydrogen bomb test

Answer 6

Rongelap Atoll natives

Question 7

is a gland lying just below the thyroid gland that can enlarge
shortly after birth in response to infection

Answer 7

thymus

Question 8

These children received
radiation doses to the thyroid gland from both external
exposure and internal ingestion of approximately

Answer 8

12 Gyt (1200 rad)

Question 9

If one computes the incidence of thyroid nodularity, considered _____, in these three groups and plots this incidence as a function of estimated dose

Answer 9

preneoplastic

Question 10

Cancer dose-response relationship

Answer 10

linear, nonthreshold

Question 11

Bone Cancer as a effect of radiation was first manifested by

Answer 11

• Radium Watch-Dial Painters

- Patients treated with radium salt

Question 12

in the 1920s and 1930s, various small laboratories
hired employees who worked at benches painting watch
dials with paint laden with

Answer 12

radium sulfate

Question 13

To prepare a fine point on the paint-brushes, the employees would touch the tip of the brush
to the tongue. In this manner, substantial quantities of
____ were ingested

Answer 13

radium

Question 14

were used because the emitted radiation, principally alpha and beta particles, would continuously excite the luminous compounds so the watch dial would glow in the dark

Answer 14

Radium salts

Question 15

Current technology uses

harmlessly low levels of _____ for this purpose aside from using radium

Answer 15

tritium (3H) and promethium

147Pm

Question 16

When ingested, the _____ behaves metabolically

similar to calcium and deposits in bone

Answer 16

radium

Question 17

Because of radium’s long half-life _____ and
alpha emission, these employees received radiation
doses to bone of up to ______

Answer 17

1620 years,
500 Gyt (50,000 rad)

Question 18

___ bone cancers in approximately 800 persons have
been observed during a follow-up period in excess of 50
years

Answer 18

72

Question 19

Bone cancer absolute risk

Answer 19

1×10^−2 Sv^−1 / (1×10^−4 rem^−1)

Question 20

Another population in whom excess bone cancer

developed consisted of _____ for a variety of diseases, from arthritis to tuberculosis

Answer 20

patients treated with radium salts

Question 21

usually begins with the development of

a radiodermatitis

Answer 21

Skin cancer

Question 22

Radiation-induced skin cancer follows a _____

dose-response relationship

Answer 22

threshold

Question 23

Skin cancer first manifested by:

Answer 23

radiation therapy recipients treated with orthovoltage (200 to
300 kVp) or superficial x-rays (50 to 150 kVp)

Question 24

orthovoltage

Answer 24

200 to 300 kVp

Question 25

superficial x-rays

Answer 25

50 to 150 kVp

Question 26

From these data, we conclude that the latent period of skin cancer is approximately ____ years, but we do not have enough data to assign absolute risk values

Answer 26

5 to 10

Question 27

Relative risk of 5 to 20 Gyt (500 to 2000 rad)

Answer 27

4:1

Question 28

Relative risk of 40 to 60 Gyt (4000 to 6000 rad)

Answer 28

14:1

Question 29

Relative risk of 60 to 100 Gyt (6000 to 10,000 rad)

Answer 29

27:1

Question 30

Breast cancer first manifested by:

Answer 30

- Patients with tuberculosis - Patients with acute postpartum mastitis - Atomic Bomb Survivors

Question 31

Lung cancer first manifested by:

Answer 31

- Bohemian pitchblende mines of Germany (Germany miners) | - American uranium miners active in the Colorado plateau (Colorado miners)

Question 32

was for many years treated by isolation in a sanitarium. During the patient’s stay, one mode of therapy was to induce a pneumothorax in the affected lung; this was done under fluoroscopy

Answer 32

Tuberculosis

Question 33

In some of tuberculosis patient populations the relative risk for radiation-induced breast cancer was shown to be as high as _____

Answer 33

10:1

Question 34

Radiation-induced breast cancer exhibits a ______ dose-response relationship

Answer 34

linear, nonthreshold

Question 35

The dose to acute postpartum mastitis patients ranged from _____

Answer 35

0.75 to 10 Gyt (75 to 1000 rad)

Question 36

The relative risk factor in patients with postpartum mastitis patients was approximately ___

Answer 36

3:1

Question 37

observations on nearly 12,000 women who received radiation doses to the breasts of ____ or more showed a relative risk of ____

Answer 37

100 mGyt, | 4:1

Question 38

On the basis of all available data regarding radiation-induced breast cancer, the best estimate for absolute risk is

Answer 38

6×10^−2 Sv^−1 | 6×10^−4 rem^−1

Question 39

Early in the 20th century, it was observed that | approximately 50% of workers in the Bohemian pitchblende mines of Germany died of ____

Answer 39

lung cancer

Question 40

it is known that radiation exposure from ____ in the mines (Germany) contributed to the incidence of lung cancer in these miners

Answer 40

radon

Question 41

The radiation exposure in these mines (Colorado) occurred because of the high concentration of _____

Answer 41

uranium ore

Question 42

is radioactive with a very long half-life of 109 years, decays through a series of radioactive nuclides by successive alpha and beta emissions, each accompanied by gamma radiation

Answer 42

Uranium

Question 43

is an alpha-emitting radionuclide that adsorbs on dust particles, which lodge in the alveolar spaces of the lung.

Answer 43

Radon

Question 44

One of the decay products of uranium is _____. This radionuclide is a gas that emanates through the rock to produce a high concentration in air

Answer 44

radon (222Rn)

Question 45

To date, more than 4000 uranium miners have been observed, and they have received estimated doses to lung tissue as high as _____; on this basis, the relative risk was approximately ___

Answer 45

``` 30 Gyt (3000 rad), 8:1 ```

Question 46

It is interesting | to note that smoking uranium miners have a relative risk of approximately ___

Answer 46

20:1

Question 47

``` Thorium dioxide (ThO2) in a colloidal suspension known as _____ was widely used in diagnostic radiology between 1925 and 1945 as a contrast agent for angiography ```

Answer 47

Thorotrast

Question 48

was approximately 25% ThO2 by weight, and it contained several radioactive isotopes of thorium and its decay products

Answer 48

Thorotrast

Question 49

Radiation that was emitted produced a dose in the ratio of approximately ____ of alpha, beta, and gamma radiation, respectively

Answer 49

100:10:1

Question 50

The use of Thorotrast has been shown to be responsible for several types of carcinoma after a latent period of approximately ____

Answer 50

15 to 20 years

Question 51

After extravascular | injection, Thorotrast is carcinogenic at the ____

Answer 51

site of the injection

Question 52

After intravascular injection, ThO2 particles are deposited in phagocytic cells of the reticuloendothelial system and are concentrated in the _____

Answer 52

liver and spleen

Question 53

Cause of liver cancer

Answer 53

Thorotrast (Thorium dioxide (ThO2)

Question 54

In 1945, The US denoted 2 nuclear warheads over the Japanese sities of Hiroshima and Nagasaki; ______ was dropped in Hiroshima on August 6, 1945, 3 days later _____ was dropped in Nagasaki, atomic bomb survivors later developed _____

Answer 54

Little boy, Fat man, Leukemia