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RT 244 ch 33,34
Radio-biology chapters 33,34
| Question | Answer |
|---|---|
| What are the 2 periods associated with acute radiation sickness? | Prodromal and Latent |
| Describe the Prodromal period: | 1.occurs within mins/hours 2.over 100 rads 3.Symptoms:nausea, vomiting, diarrhea, and a reduction in the white cells |
| Describe the Latent period: | 1.after prodromal period 2.only last hours if in excess of 5000 rads 3.can last up to weeks if between 100-500 rads 4.feeling of well being |
| Consider the latent period, what is a common mistake associated with this period? | Sometimes mistaken as early recovery from a moderate radiation dose |
| What syndromes are involved in the acute radiation sickness? | Hematologic death, Gastrointestinal death, Central Nervous System death |
| Describe Hematologic death | 1.200-1000 rads 2.can recover 3.symptoms:possible vomiting,mild diarrhea,malaise,lethargy,fever,reduction in white and red cells and platelets |
| Describe Gastrointestinal death | 1.1000-5000 rads 2.certain death between 4-10days 3.symptoms:nausea,vomiting,diarrhea,anorexia,lethargy,followed by severe diarrhea 4.destroys intestinal lining |
| Describe Central Nervous System death | 1.in excess of 5000 rads 2.certain death within 3 days 3.symptoms:more severe prodromal period symptoms,disoriented,loses muscle coordination,difficulty in breathing,seizures,loss of equilibrium,lethargy,lapse into coma and die |
| What is the most devastating human response to radiation exposure? | death |
| What is mean survival time (MST)? | the average time between exposure and death |
| What form of cancer was most common with uranium and radium miners? | Lung cancer because of high levels of radon gas |
| Identify the tissues first affected by radiation | skin,gonads,and bone marrow |
| What are the 2 most radiosensitive cells in the body? | spermatogonia and lymphocytes |
| The cells of what layer of skin are the most sensitive? | The lowest level's basel cells because they are stem cells |
| What is the goal of radiation therapy? | to kill tumor cells and cause the least amount of damage to healthy tissue |
| What is erythema? | a sunburn-like reddening of the skin |
| What is desquamation? | ulceration and denudation of the skin |
| Which bone marrow cell type will be most severely depressed after irradiation? | lymphocytes |
| What is epilation and the dose required to cause it? | 1.loss of hair 2.temporary at 300 rads 3.permanent at 700 rads |
| What is SED50? | dose of ionizing radiation required to affect 50% of persons irradiated using 500 rads |
| What doses causes permanent and temporary sterility in the testicles? | testicle dose of 500 rads cause permanent while 200 rads causes transient or temporary sterility |
| What is lethal dose? | dose that causes death |
| What does LD 50/60 mean? | dose of radiation expected to cause death within 60 days to 50% of those exposed at 350 rads |
| What minimum ovarian dose caused permanent and temporary sterility? | ovarian dose of 500 rads is permanent while 200 rads is temporary |
| Chromosomal aberrations represent the severest damage when the hit is taken by what? | DNA |
| The time frame of radiation delivered for early effects are? | high dose over short period |
| The time frame of radiation delivered for late effects are? | low dose over a long period |
| What is the key role of lymphocytes? | plays an active role in providing immunity for the body by producing antibodies |
| What is the most radiosensitive phase in male gametes? | spermatogonia |
| What is the most radiosensitive phase in female gametes? | the oocyte in the mature follicle |
| What is the study called that proved their is an overall relative risk for leukemia of approx 1.5 from diagnostic irradiation in utero? | Oxford survey by Alice Stewart in Great Britian |
| What does it mean by the severity of response is dose related? | the higher the dose the more severe the response |
| What is the term for an orderly map of all chromosomes? | Karotype |
| When is it most appropriate to perform epidemiologic studies? | When the number effected is small in a large population |
| What chromosomal aberration is most difficult to detect scientifically? | reciprocal translocation because it needs a karyotype for analysis |
| If you knew several dose levels, what model would you use to estimate risk for late effects? | absolute |
| How do you compute relative risk? | Relative = observed/expected |
| How do you compute excess risk? | Excess = observed - expected |
| Define radiodermatitis | 1.non-malignant 2.calloused, weathered skin 3.tight, brittle enough to crack |
| Describe H.J. Mueller's research | 1.1927 2.drosophila fruit fly 3.radiation does not alter the quality of mutations but increases the frequency of those mutations observed |
| Why was the contrast media Thorotrast discontinued from use for angiography? | it caused liver cancer and other carcinomas after a latent period of approx 15 to 20 years |
| Describe the Law of Bergonie and Tribondeau | radiosensitivity of living tissue varies with maturation and metabolism |
| Describe Russell's research | 1.1946 2.mice 3.a dose rate effect does exist 4.doubling dose concept was developed |
| What is the worst case estimate for radiation induced life-span shortening in days/rads? | 10 days/1 rad |
| What is the most commonly accepted estimate for radiation induced life-span shortening in days/rads? | 1 day/ 1 rad |
| What trimester of pregnancy is the most radiosensitive? | 1st trimester |
| What does the hemopoietic system consist of? | bone marrow, circulating blood, and lymphoid tissue |
| What is Cytogenetics? | the study of the genetics of cells, particulary cell chromosome |
| What are the principle late effects? | radiation induced malignancies and genetic effects |
| What are some other late effects? | life span shortening and effects on local tissue |
| Is chromosome aberrations an early or late effect? | it can be both early or late |
| Who had the chance of developing radiation induced cataracts? | past cyclotron physicists |
| What are the three types of risk estimates? | 1.relative (ratio) 2.absolute (know 2 or more doses) 3.excess (number) |
| Death from acute radiation exposure follows what type of dose-response relationship? | nonlinear, threshold |
| What cells of the hemopoietic system arise from pluripotential stem cells? | Lymphocytes,thrombocytes,erythrocytes,and granulocytes |
| The normal human karyotype consists of what? | 23 chromosome pairs |
| Which type of cancer has not been demonstrated in humans after irradiation? | colon |
Created by:
Chrslarsen
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