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How many rad is LD50/60 in humans
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varkey Mdterm exam9
| Question | Answer |
|---|---|
| Linear energy transfer: | Varies for different types of radiation |
| How many rad is LD50/60 in humans | 3 |
| Late or long-term effects of radiation exposure are represented by which of the following dose-response curves? | Linear nonthreshold |
| Damage to the cell being irradiated is called: | somatic |
| Which of the following contributes most to patient dose? | photoelectric |
| Compton interaction: | Decreases contrast in the radiographic image * |
| The dose equivalent is calculated by multiplying the absorbed dose by which of the following? | quality factor |
| Which of the following causes about 95% of the cellular response to radiation? | Indirect effect * |
| Humans can lose __________ for every rad of radiation they receive. | 10 days |
| Which type of dose-response relationship represents radiation-induced leukemia and genetic effects? | Linear, nonthreshold |
| Examples of stochastic effects of radiation exposure include:Radiation-induced malignancy, Genetic effects, Leukemia | 1,2,3 |
| If the exposure rate to an individual standing 7.0 feet from a source of radiation is 0.5 mGy/hr, what will be the dose received after 20 minutes at 3.0 feet from the source? | 0.90 mGy |
| Radiation that exits the x-ray tube from the anode is called: | Primary radiation * |
| The SI unit of absorbed dose is the: | Gray * |
| Which of the following expresses the gonadal dose that, if received by every member of the population, would be expected to produce the same total genetic effect on that population as the actual doses received by each of the individuals? | Genetically significant dose |
| Which photon-tissue interaction produces a recoil electron and a scattered photon in diagnostic radiography? | Compton * |
| What is the dose range in Gray for bone marrow syndrome? | 2- 10 |
| Most radiation-induced damage to cells occurs: | At doses of radiation much higher than that used in radiography * |
| _____________is the study of the genetics of cells, particularly cell chromosomes. | Cytogenetics |
| At which dose range does gastrointestinal syndrome from excess radiation exposure peak? | 5 Gy |
| Grenz ray therapy is exposing an individual's using_________ | Low kVp X-rays |
| Whole body dose of _____________ can cause hematologic depressions. | 0.25 Gray |
| Radiation with a high LET: | Is highly ionizing |
| What is the SI unit of occupational exposure? | Seivert |
| Which of the following is the unit of radioactivity? | Becquerel |
| Measurement of positive and negative particles created when radiation ionizes atoms in the air helps define the: | Coloumbs/Kg |
| The sequence of events that follow high level radiation exposure leading to death within days or weeks is called ____________________ | Acute radiation syndrome |
| What is the dose range in Gray for GI syndrome? | 10-50 |
| When radiation strikes the cytoplasm, which of the following will occur? | Indirect effect * |
| The greatest source of natural background radiation to humans is | Radon |
| Whole body dose of _______ can cause death | 2 Gray |
| When radiation strikes DNA, which of the following will occur? | Direct effect * |
| If a technologist is receiving 2 mGy/hr. standing 1 foot from the patient during fluoroscopy, what is his rate of exposure when he steps back to a distance of 2 feet from the patient? | 0.50 mGy/hr |
| If a technologist is exposed to 4 mGy/hr. for 45 minutes during a fluoroscopy exam, what will be her total exposure? | 3 mGy |
| Which of the following is(are) relatively insensitive to radiation? | nerve tissue |
| Reddening of the skin caused by exposure to ionizing radiation is known as___________ | Erythema |
| Highly reactive ions that have unpaired electrons in the outer shell are called: | Free radicals * |
| The photoelectric effect: | Results in absorption of the incident photon * |
| If the exposure rate is 10 R/minute at 40 inches, what will be the rate at 20 inches? | 40 R/minute |
| The process of somatic cell division is called: | Mitosis |
| Effective dose limit: | Is 500 mrem per year for the general public * |
| Which of the following period has no signs of radiation sickness? | Latent |
| The radiation dose that, if received by the entire population, would cause the same genetic injury as the total of doses received by the members actually being exposed is called: | Genetically significant dose |
| Point lesions occur when there is disruption in | Single chemical bonds |
| Muscle tissue absorbs more radiation than fat tissue because muscle tissue has which of the following? | Higher tissue density (mass/volume) |
| What is the meaning of LD 50/30? | 50% of the exposed individuals will die in 30 days |
| The blood count is depressed following a whole body dose equivalent of at least how many rads? | 25 |
| Medical x-rays are an example of: | Artificially produced radiation |
| Cataractogenesis, life span shortening, embryologic effects, and carcinogenesis are examples of: | Long-term somatic effects |
| Increased dose equals increased probability of effects best describes which of the following? | Stochastic effects |
| Attenuation | Describes changes in the x-ray beam as it travels through the patient |
| The radiation weighting factor for x-rays is: | 1 |
| The lens dose of CT scan is _____ per slice | 0.05 Gray |
| Cataractogenesis does not occur at low levels of radiation exposure. Therefore it is best expressed by which of the following dose-response relationships? | Threshold |
| The SI unit of absorbed dose is the: | Gray |
| Which photon-tissue interaction makes radiography possible because of its creation of contrast? | Photoelectric |
| the average energy of a Bremsstrahlung x-ray emission spectrum is ________ the kilovoltage-peak (KVp) selected by the radiographer | One-third of |
| X-rays may remove electrons from atoms in the body by a process called: | Ionization |
| Acute radiation syndrome follows a __________________dose response relationship. | nonlinear threshold |
| What is the SI unit of exposure in air? | C/kg |
| Grenz therapy is used for the treatment of | Tinea Capitis |
| For humans the doubling dose is approximately __________Grays | 0.50 to 2.5 |
| The master molecule that directs cell activities is: | DNA |
| Gray multiplied by a radiation weighting factor equals: | Seivert |
| Radiation hormesis suggests that very low radiation doses are beneficial. | true |
| Ionization may cause: | Unstable atoms |
| Radiation safety standards assume what relationship between dose and response? | Linear-nonthreshold |
| Graphs that demonstrate the relationship between radiation received and the organism's response are called: | Dose-response curves |
| The most common effect from exposure to ionizing radiation is: | Nothing |
| The hypothesis that tiny amounts of ionizing radiation can be beneficial is called | Radiation hormesis |
| The energy transfer of 1 joule per Kg of the irradiated material is known as _____________ | One gray |
| Skin erythema follows a _________________ dose response relationship | Deterministic, threshold |
| The average dose to active bone marrow as an indicator of somatic effects on population is called: | Mean marrow dose |
| Radiation protection is based on which dose-response relationship? | Linear-nonthreshold |
| The unit of radioactivity is the: | Becquerel Curie |
| If the intensity of the x-ray beam is inversely proportional to the square of the distance from the source, how does the intensity of the x-ray beam change when the distance from the source of radiation and a measurement point is tripled? | It decreases by a factor of 9 at the new distance |
| What is the cause of death in CNS? | Elevated fluid levels in the brain |
| The amount of radiation that causes the number of genetic mutations in a population to double is called the: | Doubling dose |
| The photon-tissue interaction in diagnostic radiography that results in the total absorption of an x-ray photon and the production of contrast in the radiographic image is: | Photoelectric |
| Leukemia has a latency period of ______________years | 4-7 |
| Which of the following states that the radiosensitivity of cells is directly proportional to their reproductive activity and inversely proportional to their degree of differentiation? | Law of Bergonié and Tribondeau |
| Effective dose limit: | Effective dose limit: |
| When considering several types of radiation regarding linear energy transfer, which of the following statements is NOT true? | Beta particles have a higher LET than alpha particles |
| What is the threshold dose for cataract? | 2 Gray |
| The amount of radiation deposited per unit length of tissue traversed by incoming photons is called: | Linear energy transfer |
| The SI unit gray is used to measure which of the following? | absorbed dose |
| Background radiation is the source of what percent of human exposure? | 82% |
| The amount of radiation deposited per unit length of tissue traversed by incoming photons is called: | linear energy transfer |
| Quality factor of Alpha particle is | 20 |
| Compton interaction: | May produce a gray fog on the image, thereby lowering contrast |
| What is the established annual occupational dose-equivalent limit for the lens of the eye? | 150 mSv |
| Radiation that is contained in the environment is called: | Natural background |
| All the following radiation-exposure responses exhibit a nonlinear threshold dose-response relationship except | Leukemia |
| Radiation doses up to ________ are considered low risk to the embryo-fetus. | 15 to 20 rads |
| The law of Bergonié and Tribondeau states that cells are more radiosensitive if they are: Highly proliferative, Highly differentiated, Immature | Highly proliferative Immature |
| the SI unit of in-air exposure is the: | Coulombs/kilogram |
| Cell damage may be exhibited as | Loss of function or abnormal function |
| What quantity of radiation exposure to the reproductive organs is required to cause temporary infertility? | 2000 mGy |
| If 1 – 10 Gy or more is received as a whole-body dose in a brief period of time, certain symptoms will occur, these are referred to as | Acute radiation syndrome |
| The SI unit of equivalent dose and effective dose is the: | Sievert * |
| A single dose of _________________ cause erythema | 2 Gray |
| Radiation effect on skin follows a ________________dose response relationship | nonlinear threshold |
| The upper boundary dose that can be absorbed that carries a negligible risk of somatic or genetic damage to the individual defines: | Effective dose limit |
| The unit of the curie would be used in what imaging modality? | Nuclear medicine |
| If an individual receives an exposure of 150 mR/h at 2 feet from a radiation source, what will be their dose after 30 minutes at five feet from the source? | 12 mR |
| If an exposure of 16 mR is recorded at 1 meter, what would the exposure rate be at 4 meters? | 1 mR |
| Cataracts follows a ______________dose response relationship | nonlinear threshold |
| Which acute radiation syndrome requires the largest exposure before any effects become apparent? | Central nervous system (CNS) |
| Radiation effects that show up in the next generation are called: | genetic |
| To eject a K- shell electron from a tungsten atom, the incoming electron must have an energy of at least | 70 KeV |
| What is the minimum dose in Gray that could cause temporary sterility: | 2 – 2.5 |
| Which of the following causes about 5% of the cellular response to radiation? | Direct effect |
| Acute radiation syndrome follows a ________________ dose response relationship. | Nonlinear threshold |
| the SI unit of dose equivalency is the: | Sievert |
| The energy of an L characteristic ray is equal to the | Difference in energy between the L and M shells |
| What is the SI unit of dose equivalent? | Sievert |
| Beta particles have a radiation weighting factor (WR) that is numerically equal to: | 1 |
| Mutations are examples of: | Genetic effects |
| Cells that are oxygenated are more susceptible to radiation damage. This describes: | Oxygen enhancement ratio |
| Our radiation protection guidelines are based on the stochastic effects of radiation and follows a ______________ dose-response relationship. | Linear non-threshold |
| Medical x-rays are an example of: | Artificially produced radiation |
| Cataract follows a _____________________ dose response relationship. | Nonlinear threshold |
| Leukemia follows a _____________dose response relationship | linear non-threshold |
| The dose required to cause erythema in 50% of those exposed is roughly | 5 Gy |
| What is the tissue weighing factor of active bone marrow? | 0.12 |
| Somatic effects of radiation: | Are caused when a large dose of high-LET radiation is received by a large area of the body |
| The average energy of the x-ray beam is increased by which of the following? Increased added filtration, Increased generator voltage ripple, Increased kilovoltage | Increased added filtration Increased kilovoltage |
| Which photon-tissue interaction produces radiation that may expose others in the room during fluoroscopy? | compton |
| Which interaction between x-ray photons and matter involves partial transfer of the incident photon energy to the involved atom? | compton |
| Cataract usually occur on the ___________________ of the lens | posterior pole |
| ____________ Trimester during pregnancy is the most radio-sensitive period. | first |
Created by:
daniel.velazco004