The lethal dose of ionizing radiation for humans is usually given as follows:
LD 50/60
Acute radiation syndrome presents in four major response stages. In what order do these stages occur?
Prodromal, latent period, manifest illness, recovery or death
Which of the following systems is the most radiosensitive vital organ system in human beings?
Hematopoietic
When cells are exposed to sublethal doses of ionizing radiation, approximately _____ of radiation- induced damage may be repaired over time, and about ________ is irreparable.
90%
10%
As radiation dose increases, the severity of early deterministic effects:
also increases
The total radiation dose received by a somatic or genetic cell and the dose rate determine the:
production of chromosome aberrations
In 1898, after developing burns attributed to radiation exposure, this Boston dentist began investigating the hazards of radiation exposure and became the first advocte of radiation protection. who is this person?
William Herbert Rollins
In the female, the ovarianstem cells:
multiply to millions of cells only during fetal development, before birth, and then steadily decline in number throughout life
Which of the types of the following cells develop from a single percursor cell, the pluripotential stem cell?
1. lymphocytes and granulocytes
2. thrombocytes and erythrocytes
3. platelets
1, 2. and 3
With regard to raditaion exposure, which part of the gastrointestinal tract is most severly affected?
small intestine
Spealized, nondividing cells that are relativly radioresistant
mature spermatogonia
Early somatic effects on organ systems that result from high doses of radiation.
deterministic effects
A single prescursor cell from which all cells of the hematopoietic system develop
pluripotenial stem cell
Form of ARS that occurs when humans recieve whole body doses of ionizing radiation ranging from 1Gy to 10Gy
bone marrow syndrome
Functions as an ongoing regeneration system for the human body; is relatively radiosensitive
skin
Immmature female growth cells
oocytes
Population inadvertently subjected to high levels of fallout during an atomic bomb test in 1954
Marshal Islanders
Result when an organ or tissue fails to recover from radiation exposure
Necrosis, or death
What radiation exposure causes the number of red cells, white cells, and platelets in the circulating blood to do
decrease
An abnormal decrease in the white blood corpuscles, usually below 5000/mm^3
Leukopenia
Period during the female menstural cycle when a maure follicle releases an ovum
Ovulation
Form of ARS that appears at a threshold dose of approximately 6 Gy
gastrointestinal syndrome
Whole-body dose of ionizing radiation that can be lethal to 50% of an exposed population within 30 days
LD 50/30
Middle layer of skin
dermis
A method of dose assesment in which biologic markers or effects of radiation exposure are measured and the dose to the organism is inferred from previously established dose effect relationships
biologic dosimetry
Period of time when periodic blood counts were the only means of radiation exposure monitoring for radiation workers engaged in radiologic practices
1920's and 1930's
Radiation sickness that occurs in humans after whole-body reception of large doses of ionizing radiation ( 1Gy or more) delivered over a short time
ARS
A decrease in the number of blood cells in the circulating blood can result in a lack of vitality and this condition
Anemia
The period after the initial stage of ARS during wich no visible effects or symptoms of radiation exposure occur
latent period
Thermal trauma
burns
Following a period of bout a week, during which no visible sypmtoms occur, symptoms again become visible during this stage of ARS
manifest illness
The first stage in ARS, which occurs within hours after a whole- body absorbed a dose of 1 Gy or more; characterized by nausea, vommiting, diarrhea, fatigue, and leukopenia
prodromal stage
Deviation from normal development or growth
chromosome aberrations
Form of ARS that results when the central nervous system and the cardiovascular system receive ionizing radiation doses of 50 Gy or more
cerebrovascular syndrome
Alopecia
epilation
When biological effects from ionizing radaition demonstrate the existence of a threshold and the severity of that damage increases as a consequence of increased absorbed dose, the events are considered:
deterministic
Approximately what percentage of the human body's surface skin cell is replaced daily by stem cells from an underlying basal layer?
2%
A cytogenic analysis of chromosomes may be accomplished through the use of a chromosme map. This map is called:
karyotype
During the age of approximately 12 to 50 years, how many mature ova will a female produce?
400-500
Which of the following are parts of the hematopoietic system?
1. Bone marrow
2. Circulating blood
3. Lymphoid organs
1, 2, and 3
Many early radiologists and dentists developed a reddening of the skin caused by exposure to ionizing radiation. This condition is called:
Radiodermatitis
Which of the following measures of lethality may be a more relevant indicator of outcome for humans?
LD 50/60
On which of the following factors does somatic or genetic radiation-induced damage depend?
1. the amount of body area exposed
2. the quantity of ionizing radiation to which the subject is exposed
3. the specific parts of the body exposed
1, 2, and 3
In humans with the gastrointestinal form of ARS, the part of the body most severly affected is the:
small intestine
Following whole-body reception of large doses of ionizing radiation delivered over a short period of time, which of the following medical problems occurs in humans?
Acute radiation syndrome
The use of high-level fluroscopy for extended periods of time can result in
radiation induced skin injuries for patients
What do the atomic bomb survivors of Hiroshima and Nagaski, the Marshall Islanders inadvertently subjected to high levels of fallout during an atomic bomb test in 1954, and the nuclear raditaion victims of the 1986 Chernobyl distater have in common?
all were exposed to doses of ionizing radiation sufficeint to cause ARS in many group members
Which of the following factors govern organ and tissue response to radiation exposure?
1. Growth rate
2. radiosensitivity
3. reproductive characteristics
1, 2, and 3
Which of the follwoing does not cause early deterministic somatic effects of ionizing radiation?
doses encountered in diagnostic radiology
The hematopoietic, gastrointestinal, and cerebrovascular syndroes are three seperate dose related syndromes that are part of the:
total-body syndrome
Without effective physical monitoring devices, what biologic criteria would play an important role in the identification of radiation casualties during the first 2 days after a nuclear diaster?
occurance of nausea and vomiting
Without medical support, the lD 50/30 for adult humans is estimated to be:
3.0 to 4.0 Gy
Infection, hemmorhage, and cardiovascular collapse are symptoms that can occur as part of acute radiation syndrome during the:
1. Initial stage
2. Latent period
3. stage called manifest illness
3 only: latent period
Which of the following local tissues will experience immediate consequences from high radiation doses?
1 bone marrow
2. male and femaal reproductive organs
3. skin
1, 2. and 3
Imaging procedures generally result in:
relatively low doses of gonadal radiation for the patient and for imaging personnel
Which of the following are accessory structures of the skin?
1. hair follicles
2. sabaceous glands
3. sweat glands
1, 2, and 3
When cells are exposed to subletha doses of ionizing radiation, repair and recovery may occur because cells:
contain a repair mechinism inherent in their biochemistry (repair enzymes)
The tests of the human male and the ovaries of the female do not respond the same way to irradiation because:
there is a difference in the way in which male and female germ cells are porduced and progress from elementary stem cells to mature cells
When are human ovaries most radiosensitive?
during the fetal stages of early life and during childhood
ARS is actually a collection of symptoms associated with:
exposure to high-level radiation
Current radiation protection programs rely on hematologic depression as a means for monitoring imaging personnel to assess if they ahve sustained any degree of radiation damage from occupation exposure.
True/False
False: Current radiation protection programs do not rely on hemtologic depression as a meas for monitoring imaging personel
If cells that are needed to clot blood are depleted, the risk of hemorrhage decreases.
True/False
False: The risk of hemorrhage increases
Telophase is the phase of cell divison in which chromosomal damage caused by radiation exposure can be evaluated.
True/False
False: Chromosomal damage caused by radiation exposure can be evaluated during metaphase
If the effects of ionizing radiation are cell killing and directly related to the dose recieved, they are called deterministic somatic effects.
True/False
True
A person who has recieved a radiation exposure sufficient to cause radiation sickness will experience the intial stage of the syndrome within hours after the whole body absorbed dose. After this stage, no visible symptoms occur for about one week.
True/Fa
True
Radiation exposure causes an increase in the number of red cells, white cells, and platelets in the circulating blood.
True/False
False: Radiation exposure causes a decrease in the number of red cells, white cells, and platelets in the circulating blood
The LD 50/30 for adult humans is estimated to be 8 to 9 Gy.
True/False
False: The LD 50/30 for adult humans is estimated to be 3 to 4 Gy
The japanese atomic bomb survivors of Hiroshima and Nagaski are examples of human population with ARS as a consequence of war.
True/False
True
Patients who underwent eaadiation therapy and who recieved orthovoltage radiation therapy treatments provide significant evidence of skin damage cause by radiation exposure.
True/False
True
Early deterministic somatic effects occur wihin a long period of time after exposure to ionizing radiation.
True/False
False: Early deterministic somatic effect occur within a short period of time after exposure to ionizing radiation
Ionizing radiation produces the greatest amount of biologic damage in the human body when a small dose of sparsely ionizing (low-LET) radiation is delivered to a small or radiosenstive area of the body.
True/False
False: Ionizing radiation produces the greatest amount of biologic damage in the human body when a large dose of densley ionizing (low-LET) radiation is delivered to a large or radiosenstive area of the body.
ARS actually is a collection of symptoms associated with low-LET radiation exposure.
True/False
False: ARS is actually a collection of symptoms associated with high LET radiation exposure
Intestinal disorders are caused by radiation damage to the sensitive epithelial tissue lining the intestines.
True/False
True
Radiation doses ranging from 1 to 10 Gy produce an increase in the number of bone marrow stem cells
True/False
False: Radiation doses in this range produce a decrease in the number of bone marrow stem cells
In the human female, a gonadal dose of 0.1 Gy may delay or suppress menstruation.
True/False
True
Whole body equivelent doses greater than 1 Gy are considered fatal regardless of medical treatment
True/False
False: Whole body equivalent doses greater than 12 Gy are considered fatal regardless of medical treatment
Moderate radiation doses can cause temporary hair loss, and large radiation doses can result in permanent hair loss
True/False
True
Chromosomal damage can be caused by both low and high radiation doses.
True/False
True
Karyotyping is done during anaphase, when each chromosme can be individually demonstrated and radiation induced chromosome and chromatid aberrations can be observed
True/False
False: Karyotyping is done during metaphase
As a result of the effects of the atomic bomb in Japan and the nuclear accident at Chernobyl, the medical community has recognized the need for a thorough understanding of ARS and appropriate medical support of victims.
True/False
True
The massive explosion at the Chernobyl nuclear power plant on April 26, 1986. ejected several tons of buring graphite, uranium, dioxide fuel, and other contaminants vertically into the atosphere in a 3 mile high radioactive plume of intense heat
True/Fals
True
LD 50/30 for humans may be more accurate than LD 50/60
True/False
False: LD 50/60 may be more accuraate for humans than LD 50/30
The workers and firefighters at Chernobyl are examples of humans who dies as a result of gastrointestinal syndrome
True/False
True
Only some layers of the skin and its accessory structures are actively involved in the response of the tissue to radiation exposure
True/False
False: All layers of the skin and accessory structures are actively involved
Highly, specialized, nondividing cells in the circulation blood with the exception of lymphocytes are relatively insensitive to radiation
True/False
True