The total body response to radiation is presented in terms of 3 ______ ______
Characteristics of each syndrome are dependent on the ______ received and exposure conditions.
What are the 3 specific exposure conditions that apply in dealing with radiation syndromes?
1. exposure must be acute (minutes)
2. total body or nearly total body exposure must occur
3. exposure must be from an external penetrating source rather than ingested, inhaled, or implanted radioactive sources.
What are the 3 syndromes
What is the hemopoetic syndrome
blood syndrome that has a deficiency of WBCs, lymphocytes and platelets.
What is induced by a total body dose of 100-1000 cGy?
In hematopoetic syndrome LD 50/60 for humans is estimated to be between_____ and ______ by varies with ____, _____, and _______
age, health, and gender
Who is more resistant to get the hematopoetic syndrome?
females and the middle aged person
males and very young and old are more sensitive
What is the depression of all blood cell counts
Note for hematopoetic syndrome
most patients receiving less than 300cGY will survive and eventually recover over 3-6 month period
After 300-500 cGy death may occur in 4-6 weeks
After 500-1000 cGy death is likely within 2 weeks.
No record exists of human survival when the total body dose exceeds 1000 cGy.
Which syndrome is induced if the total body dose is between 1000 and 10,000 cGy?
Which syndrome can also be induced at a dose as low as 600 cGy and overlaps with the cerbrovascular syndrome at doses of 5000 cGy or more?
What is the mean survival time for the gastrointestinal syndrome?
3-10 days or up to 2 weeks with medical support
How does the gastrointestinal syndrome occur?
as a result of damage to the gastrointestinal tract and bone marrow.
What is the most radiosensitive portion of the digestive system?
After exposure doses of _______, severe depopulation of crypt cells leads to partial or complete denudation (wearing away) of the villi lining the lumen of the small intestine.
This syndrome was formerly known as the _____ _____ _____ _______and occurs exclusively after doses of 10,000 cGy or more.
central nervous system syndrome
Which syndrome can overlap the gastrointestinal syndrome because it can be induced by a dose as low as 5000 cGy?
How fast can deat occur after the cerbrovascular syndrome doses at over 10,000 cGy?
several days or less
what can damage the developing embryo and fetus in utero?
how is radiation damage manifested when given in utero?
as lethal effects, congenital abnormalities present at birth or late effects observed years later.
How can the below effects be produced?
lethal effects, congenital abnormalities present at birth or late effects observed years later.
1. irradiation of the sperm or ovum before fertilization, thus resulting in inherited effects
2. exposure of the fetus to radiation , thus resulting in congenital defects.
What are the newly formed balls of cells known as?
At what stage is it considered an embryo?
10 days to 6 weeks
At the end of the 6th week of pregnancy, what is it called?
Unlike the adult the _____ _____ _____ is responsive to radiation and can be damaged at relatively low doses.
fetal nervous system.
Hematopoetic Syndrome dose range is
Hematopoetic Syndrome recovery time is
dose dependent- 3 weeks to 6 months; some people do not survive
Hematopoetic Syndrome time of death?
3 weeks to 2 months
Hematopoetic Syndrome organ and system damaged?
Hematopoetic Syndrome signs and symptoms
Decreased # of stem cells in bone marrow
increased amt of fat in bone marrow
pancytopenia (depression of all blood counts)
Gastrointestinal Syndrome dose range
Gastrointestinal Syndrome time of death
Gastrointestinal Syndrome organ and system damage
Gastrointestinal Syndrome signs and symptoms
denudation (wearing down) of villi in small intestine
bone marrow depression
Gastrointestinal Syndrome recovery time
Cerebrovascular Syndrome dose range
> 5000 cGy
Cerebrovascular Syndrome time of death
Cerebrovascular Syndrome organ and system damaged
Cerebrovascular Syndrome signs and symptoms
Cerebrovascular Syndrome recovery time
What should not exceed .5 rem (5 mSv) with monthly exposure not exceeding .05 rem )0.5 mSv) ?
The maximum permissible dose to the fetus during the entire gestational period from occupational exposure of the mother
The _____ _______ dose to the fetus during the entire gestational period from occupational exposure of the mother should not exceed .5 rem (5 mSv) with monthly exposure not exceeding .05 rem )0.5 mSv) ?
what are the most radiosensitive forms of animals and humans?
embryo and the fetus
in regard to fetal effects of radiation, the principal factors of importance are......
the dose and the stage of gestation at which it was delivered
Because the latent period for an effect from radiation is inversely proportional to radiation does, the biological response to low dose is not observable for extended periods of time ranging from years to generations. These effects are known as late effects and are termed ____ _____ if body cells are involved and ____ _____ if reproductive (germ) cells are involved
What is the time interval between irradiation and the appearance of a malignancy?
What is the most important late somatic effect induced by radiation?
Radiation is classified as a
carcinogen or cancer-causing agent
What is considered to be an all or nothing event?
Any dose no matter how low, has some potential of inducing _____
What is a non threshold even with the probability of an effect increasing as the dose increases?
Carcinogenesis is an example of a ____ _____ in which every dose carries some magnitude of risk
The latent period for leukemia induction by radiation is usually ____ to _____ _____ with the peak incidence approx____ to ____ _____ after exposure
Radiation induced solid tumors have a latent period ranging from
20-30 years or longer
When and where was the 1st radiation induced skin cancer?
1902 on the hand of a radiologist
what have been the most frequently observed skin cancers following radiation exposure?
squamous cell and basal cell carcinomas
when the young female watch dial painters licked their brushes that had radium paint on the tip to paint the clock faces, what did they develop in 1915-1930
osteosarcoma or bone cancer
What is the naturally occurring deposits of radioactive materials in the rocks of the earth and decay thru a long series of steps until they reach a stable isotope of lead?
The dose range from 1200-6000 cGy was a popular treatment for what and had a 100 fold increase in thyroid cancer
Irradiation of the enlarged thymuses in children before the 1930s
Ionizing radiation is known as a
somatic late effects can occur in an irradiated individual, and exposure of reproductive (germ) cells in that individual may affect future generations.
The # of spontaneous mutations that occur in each generation of an organism is
If the mutation frequency in a generation is doubled by exposure to radiation, the radiation dose is known as
What is the TD 5/5 for bladder
What is the TD 5/5 for the rectum
What is the TD 5/5 for the Lens
What is the TD 5/5 for the Fetus
What is the TD 5/5 for the heart
What is the TD 5/5 for the Intestine
What is the TD 5/5 for the kidney
What is the TD 5/5 for the Liver
What is the TD 5/5 for the lung
What is the TD 5/5 for the spinal cord
What is TD 5/5
The tissue dose associated eith a 5% injury rate within 5 years
what is TD 50/5
tissue dose associated eith a 50% injury rate within 5 years
what is TD 5/5 for the brain
What is the TD5/5 for the esophagus
What is the goal of Radiation therapy
To eradicate the tumor all the while not destroying normal tissue
___ ____ can be induced in tumor AND in normal tissues
The tolerance dose of the normal tissue limits the ____ that can be administered to the tumor
What is the functional cells of an organ (mutant cells)
What are connective tissue cells called
Describe cells belonging to group 1 of parenchymal
responsible for tumor growth
the % of group 1 cells in a tumor varies from ___ to ____ and is termed ___ ____
The ____ _____ typically decreases as the size (volume) of the tumor increases
describe cells belonging to group 2 of parenchymal
basically in the G0 phase
Which cells have retained the ability to re enter the cell cycle and divide if properly stimulated?
G0 phase or group 2
Which group is not viable
3 and 4
The rate at which tumors grow depends on 3 major factors
the division rate of proliferating parenchymal cells
the % of these cells in the tumor
the degree of cell loss from the tumor
What is characteristically unorganized compared with that of normal cells
During the early stages, tumors begin to outgrow their_____ _____
Differing levels of O2 availability is
oxygen tension PO2
Tumors located more than 200 um from the nearset blood vessels (capillaries) are ____ and unable to proliferate
What do anoxic cells that have died form?
Tumor cells closest to blood vessels are well oxygenated and called _____ and are actively dividing and compose the GF of the tumor
Gradually decreased O2 tensions are
15% or more of the tumor cell population may be ____ and this is known as the ___ ____ of the tumor
The vasculature network that forms in each growing tumor with factors such as division rate, GF, cell loss, ultimately gives rise to ___,____,and ____ cell populations in the tumor.
What is the #1 radiosensitizer
The biologic effects on tissue from fractionated radiation therapy depend on the
What are the most radiosensitive phases
G2 and M
What results in a redistribution of surviving cells after radiation
When you irradiate a cell population that is in various phases, typically results in death of cells in G2 and M and survival to cells in S, this process is known as
What has occurred within hours of radiation exposure in normal and tumor cells in vitro?
Repairs of sublethal damage
What takes advantage of repair processes in normal tissues that are active between radiation fractions?
Fractionated radiation treatment
Repair of sublethal damage is ____ dependent
Because a proportion of tumor cells are thought to be ____, tumors in general are presumed to be incapeable of repairing sublethal radiation damage as efficiently as normal tissues
Which R only applys to tumors?
What is the process by which hypoxic cells gain access to O2 and become radiosensitive between radiation fractions?
what decreases during fractionation of xrays and gamma rays
O2 enhancement ratio
what 5 methods have been used with varying degrees of success of improved tumor response
high LET radiations
what related the treatment schedule in terms of total dose and time with clinical outcome including early and late effects and tumor cure?
The use of ___ ____ led to treatment schedules fro fractionate XRT that gave a high probability of tumor control without exceeding the tolerance of normal tissue
What has reduced radiation toxicity to surrounding tissues altering the ratio of normal tissue dose to tumor dose?