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BLY FINAL
Question | Answer |
---|---|
Attenuation | describes changes in the x-ray beam as is travels through the patient |
Which Photon- tissue interaction makes radiography possible because of its creation of contrast? | photoelectric effect |
Which photon-tissue interaction produces radiation that may expose others in the room during fluroscopy? | Compton's |
The traditional unit of absorbed does is the | Rad |
Measurement of positive and negative particles created when radiation ionizes atoms in the air define the: | Roentgen |
Linear energy transfer | varies for different types of radiation |
Graphs that demonstrate the relationship between radiation received and the organism's response are called | dose- response curves |
Medical x-rays are examples of | artificially produced radiation |
Cataractogenesis does not occur at low levels of radiation exposure. Therefore it is best expressed by which of the following dose-response relationship? | threshold |
Increased dose equals increased probability of effects best describes which of the following? | Nonstochastic effects |
The cumulative occupational exposure for a 22 year old radiographer is; | 22 rem |
The annual effective absorbed dose equivalent limit for the general public, assuming frequent exposure, is: | 0.1 rem |
The secondary protective barrier used in room shielding must be at least how thick? | 1/32 inch Pb Equivalent |
The intensity of scattered beam is 1/1000 the intensity of the primary beam at a _____ angle 1 meter from the patient. | 90 |
The minimum source-to-skin distance for fixed fluoroscopy is | 15 inches |
The minimum source-to-skin distance for mobile x-rays is | 12 inches |
The use of gonadal shielding on female patients may reduce gonad dose by up ____ percent | 50 |
Cells that are oxygenated are more susceptible to radiation damage. This describes | oxygen enhancement ratio |
Which of the following agencies is responsible for enforcing radiation safety standars | NRC |
The blood count is depressed following a whole body dose equivalent of at least how many rads? | 25 |
Determine the cumulative effective dose (CED) to the whole body of an occupationally exposed person who is 27 years old. | 270 mSv |
Biologic effects such as cataracts that result form exposure to ionizing radiation appear to have which of the following? | Sigmoid threshold dose-response curve |
Why have occupational and nonoccupational effective dose limits been developed by scientists? | To minimize the risk of harmful biologic effects for the general public, patients, and radiologic professional s |
Highly reactive ions that have unpaired electron in the outer shill are called: | Free radicals |
The master molecule that directs cell activities is: | DNA |
The process of somatic cell division is called: | Mitosis |
The most common effect from exposure to ionizing radiation is | ionization of atoms in the cells |
Most radiation-induced damage to cells occurs: | at dose of radiation much higher than that used in radiography |
Radiation doses up to _______are considered low risk to the embryo-fetus. | 5 rads |
A concept of radiologic practice that encourages radiation users to adopt measures that keep the dose to the patient and themselves at a minimum level is called: | ALARA |
are nerve cells relatively insensitive to radiation or sensitive? | insensitive |
Somatic effects of radiation | are caused when a large dose of high- let radiation is received by a large area of the body |
the best way to keep radiation does to the patient low is | avoiding repeat exposure |
X-rays may remove electrons form atoms in the body by a process called: | ionization |
Ionization may cause: | unstable atoms, production of low-energy x-rays, formation of new molecules harmful to the cell |
Cell damage may be exhibited as | loss of function or abnormal function |
Damage to the cell being irradiated is called | molecular |
Radiation effects that show up in the next generation are called: | genetic |
Radiation that is contained in the environment is called | natural background |
Background radiation is the source of what percent of human exposure? | 82% |
The annual effective dose equivalent per person form natural background radiation is approximately | 295 rem |
The greatest source of natural background radiation to humans is: | radon |
The smallest particle of an element that retains the characteristic of the element is a(n) | atom |
Atomic Mass refers to : | the number of protons plus the number of neutrons |
X-rays travel as bundles of energy called | photons |
The height of a sine wave is called | amplitude |
The number of x-ray waves passing a given point per unit time is called | frequency |
The transformer that operates on the principle of self-induction is the | autotransformer |
Electric timers used in x-ray equipment allow for exposure times as low as: | 1/1000 second |
to ensure consistency of radiographic quality form one exposure to the next, what device may be used: | Automatic exposure control |
When quality control test is performed to ensure that the penetrating ability of the x-ray beam is accurate, the result must be within this amount of the control panel setting: | 2 percent of SID |
What happens when a predetermined level of ionization is reached in the ionization chamber? | the exposure is terminated |