6.2 Biologic Effects of Radiation Flashcards
Approximately ___ of all deaths are caused by
cancer; therefore, any radiation-induced cancers
are obscured.
20%
Thyroid Cancer as a effect of radiation was first manifested by
- Ann Arbor series and the Rochester series
- Rongelap Atoll natives
Consisted of individuals who were treated
shortly after birth for thymic enlargement
Ann Arbor series and the Rochester series
The thymus gland was irradiated with doses up
to ____ and would shrink so small the
enlargement would disappear
5 Gyt (500 rad)
No additional problems were evident until _____ later, when thyroid nodules and thyroid
cancer began to develop in some of these
patients
20 years
21 children were subjected to high levels of radiation
fallout during a hydrogen bomb test
Rongelap Atoll natives
is a gland lying just below the thyroid gland that can enlarge
shortly after birth in response to infection
thymus
These children received
radiation doses to the thyroid gland from both external
exposure and internal ingestion of approximately
12 Gyt (1200 rad)
If one computes the incidence of thyroid nodularity, considered _____, in these three groups and plots this incidence as a function of estimated dose
preneoplastic
Cancer dose-response relationship
linear, nonthreshold
Bone Cancer as a effect of radiation was first manifested by
- Radium Watch-Dial Painters
- Patients treated with radium salt
in the 1920s and 1930s, various small laboratories
hired employees who worked at benches painting watch
dials with paint laden with
radium sulfate
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
radium
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
Radium salts
Current technology uses
harmlessly low levels of _____ for this purpose aside from using radium
tritium (3H) and promethium
147Pm
When ingested, the _____ behaves metabolically
similar to calcium and deposits in bone
radium
Because of radium’s long half-life _____ and
alpha emission, these employees received radiation
doses to bone of up to ______
1620 years, 500 Gyt (50,000 rad)
___ bone cancers in approximately 800 persons have
been observed during a follow-up period in excess of 50
years
72
Bone cancer absolute risk
1×10^−2 Sv^−1 / (1×10^−4 rem^−1)
Another population in whom excess bone cancer
developed consisted of _____ for a variety of diseases, from arthritis to tuberculosis
patients treated with radium salts
usually begins with the development of
a radiodermatitis
Skin cancer
Radiation-induced skin cancer follows a _____
dose-response relationship
threshold
Skin cancer first manifested by:
radiation therapy recipients treated with orthovoltage (200 to
300 kVp) or superficial x-rays (50 to 150 kVp)
orthovoltage
200 to 300 kVp
superficial x-rays
50 to 150 kVp
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
5 to 10
Relative risk of 5 to 20 Gyt (500 to 2000 rad)
4:1
Relative risk of 40 to 60 Gyt (4000 to 6000 rad)
14:1
Relative risk of 60 to 100 Gyt (6000 to 10,000 rad)
27:1
Breast cancer first manifested by:
- Patients with tuberculosis
- Patients with acute postpartum mastitis
- Atomic Bomb Survivors
Lung cancer first manifested by:
- Bohemian pitchblende mines of Germany (Germany miners)
- American uranium miners active in the Colorado plateau (Colorado miners)
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
Tuberculosis
In some of tuberculosis patient populations the relative risk for radiation-induced breast cancer was shown to be as high as _____
10:1
Radiation-induced breast cancer exhibits a ______ dose-response relationship
linear, nonthreshold
The dose to acute postpartum mastitis patients ranged from _____
0.75 to 10 Gyt (75 to 1000 rad)
The relative risk factor in patients with postpartum mastitis patients was approximately ___
3:1
observations on nearly 12,000 women who received
radiation doses to the breasts of ____ or more
showed a relative risk of ____
100 mGyt,
4:1
On the basis of
all available data regarding radiation-induced breast
cancer, the best estimate for absolute risk is
6×10^−2 Sv^−1
6×10^−4 rem^−1
Early in the 20th century, it was observed that
approximately 50% of workers in the Bohemian pitchblende mines of Germany died of ____
lung cancer
it is known that radiation exposure from ____ in the mines (Germany) contributed to the incidence of lung cancer in these miners
radon
The radiation exposure in these mines (Colorado) occurred because of the high concentration of _____
uranium ore
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
Uranium
is an alpha-emitting radionuclide that
adsorbs on dust particles, which lodge in the
alveolar spaces of the lung.
Radon
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
radon (222Rn)
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 ___
30 Gyt (3000 rad), 8:1
It is interesting
to note that smoking uranium miners have a relative risk of approximately ___
20:1
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
Thorotrast
was approximately 25%
ThO2 by weight, and it contained several radioactive
isotopes of thorium and its decay products
Thorotrast
Radiation that was emitted produced a dose in the ratio of approximately ____ of alpha, beta, and gamma radiation,
respectively
100:10:1
The use of Thorotrast has been shown to be responsible for several types of carcinoma after a latent period
of approximately ____
15 to 20 years
After extravascular
injection, Thorotrast is carcinogenic at the ____
site of the injection
After intravascular injection, ThO2 particles are deposited in phagocytic cells of the reticuloendothelial system
and are concentrated in the _____
liver and spleen
Cause of liver cancer
Thorotrast (Thorium dioxide (ThO2)
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 _____
Little boy,
Fat man,
Leukemia
