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Which photon-tissue interaction makes radi-ography possible because of its creation of contrast?
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BMO test #1
BMO State Board Test #1
| Question | Answer |
|---|---|
| Attenuation | Describes changes in the x-ray beam as it travels through the patient |
| Which photon-tissue interaction makes radi-ography possible because of its creation of contrast? | Photoelectric |
| Which photon-tissue interaction produces ra-diation that may expose others in the room during fluoroscopy? | Compton |
| The traditional unit of absorbed dose is the | Rad |
| The traditional unit of activity is the | Curie |
| Measurement of positive and negative parti-cles created when radiation ionizes atoms in the air helps define the | Roentgen |
| Linear energy transfer | Varies for different types of radiation |
| The unit of the curie would be used in what imaging modality? | Nuclear medicine |
| Graphs that demonstrate the relationship be-tween radiation received and the organism's response are called | Dose-response curves |
| Medical x-rays are an example 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 relationships? | Threshold |
| Increased dose equals increased probability of effects best describes which of the following? | Stochastic effects |
| The cumulative occupational exposure for a 22-year-old radiographer is: | 22 rem |
| The annual effective dose limit for the general public, assuming frequent exposure, is: | 0.1 rem |
| The secondary protective barrier used in roomshielding must be at least how thick? | 1/32 inch Pb equivalent |
| The intensity of the scattered beam is 1/1000 the intensity of the primary beam at a _____ angle 1 meter from the patient, | 90-degree |
| If the radiation dose 6 feet from the x-ray table is 5 R, what is the dose at a distance of 3 feet? | 20 R |
| The minimum source-to-skin distance for fixed fluoroscopes is | 15 inches |
| The use of gonadal shielding on female patients may reduce gonad dose by up to: | 50% |
| Cells that are oxygenated are more susceptible to radiation damage. This describes: | Oxygen enhancement ratio |
| The blood count is depressed following a whole body dose equivalent of at least how many rads? | 25 |
| Highly reactive ions that have unpaired elec-trons in the outer shell 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: | Nothing |
| Most radiation-induced damage to cells occurs: | At doses of radiation much higher thanthat used in radiography |
| Radiation dose up to _____ are considered low risk to the embryo-fetus. | 15 to 20 rads |
| A concept of radiologic practice that encourages radiation users to adopt measures that keep the dose to the patient and themselves at minimum levels is called: | ALARA |
| Which of the following is(are) relatively insen¬sitive to radiation? | Nerve tissue |
| Somatic effects of radiation | Are caused when a large dose of high-LETradiation is received by a large area of thebody |
| The best way to keep radiation dose to the patient low is: | Avoiding repeat exposures |
| X-rays may remove electrons from atoms in the body by a process called | Ionization |
| lonization may cause: | Unstable atoms |
| Cell damage may be exhibited as: | Loss of function or abnormal function |
| Damage to the cell being irradiated is called | Somatic |
| 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 per person from natural background radiation is approximately | 295 mrem |
| The greatest source of natural background radiation to humans is | Radon |
| The smallest particle of an element that retains the characteristics of the element is an | 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 |
| Electronic timers used in x-ray equipment allow for exposure time as low as | 1/1000 sec |
| To ensure consistencey of radigraphic quality from one exposure to the next, what device may be used | automatic exposure control |
| What happens when a predentminded level of ionization is reached in the ionization chamber | The exposure is terminated |
| An x-ray machine that uses a continually decreasing mA for the shortest times possible uses a | falling load generator |
| An x-ray machine that makes maximum use of heat loading potential uses a | falling load generator |
| Devices in the x-ray circuit that operates on the principle of mutual induction are called | Transformers |
| The high-voltage secction of the x-ray ciruit makes use of what type of transformer | Step-up |
| The device in the x-ray circuit that changes AC to DC is the | Rectifier |
| What type of current is required for proper operation of the x-ray tube? | Direct |
| Modern rectifiers are made of | Silicon-base semicondutors |
| The result of thermionic emmission is a | electron cloud |
| The focusing cup is located at the | Cathode (-) |
| An interaction that produces x-rays at rge anode as a result of outer-shell electrons filling hole in the K-shell is called | Characteristic |
| When a quality control test is performed to ensure that adjacent mA stations are accurate, the results must be within this amount of one another: | 10% |
| When a quality control test is performed to ensure that the same exposure factor produces consistent x-ray output, successive exposure must be within this amount of one another | 5% |
| When a quality control test is performed to enusre that the collimator is providing appropriate radiation protection, the result must be within this amount | 2% of SID |
| When a quality control test is performend 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 | 4 |
| In digital fluoroscopy, the image should be viewed on what device to take advantage of the digital capabilities? | High- resolution monitor |
| A primary advantage of digital fluoroscopy is | Postprocessing manipulation of the image |
| The active portionof a CR imaging plate is | Photostimulable phosphor |
| Energy in a CR imaging plate is released after exposure to | Laser beam |
| In digital fluoroscopy and computed radiography, the energy must be changed to digital form by a | Analog-to-digital converter |
| An algorithm is | a mathematical formula used to reconstruct the image in digital imaging |
| In computed radiography, each pixel corresponds to a shade of gray representting an area in the patient known as a | Voxel |
| A digital image is composed of rows and columns known as a | Matrix |
| Image brightness in computed radiography may be adjusted by | Changing the window level |
| The window level in computed radiography is the | Midpoint of densities |
| Radiographic contrast in computed radiography may be adjusted by changing the | window width |
| The amount of darkness on a radiograbh is controlled primarily by | mAs |
| The visible image contained in the emulsion of a film is called | Manifest image |
| The quantity of x-ray produced is directly controlled by | mAs |
| The rule or law that governs changing technique using kVp is the | 15% rule |
| If the SID is halved, what may be said about radiographic density | Density is quadrupled |
| The crossover rollers in the processor should be cleaned | twice daily |
| Speed, contrast, and base plus fog should checked on every processor | Daily |
| The contrast step used during senitometric testing is located where on the H & D curve? | Body,just below the shoulder |
| A malfuntion in which the developer temperature runs too low will cause | Light films |
| A situation in which fixer solution has entered the developer tank will cause | Fogged films |
| In which section of the process are silver halide crystals converted to black metallic silver | Developer |
| In which section of the processor might the oder of ammonia indicate a problem | Developer |
| Which of the following system agitates and circulates the developer solution? | Recirculation |
| Which of the following grid errors will result in an image that shows normal density in the middle but decreased density on the sides and may follow removal and replacement of the grid | Upside down |
| Grid frequency is described as the | Number of lead strips per inch or centimeter |
| The portion of an intensifying screen that contains phosphors is the | active layer |
| A slower film-screen system will show | Wider latitude |
| A faster Film-screen system will exhibit | poorer recorded detail |
| The section of an H & D curve that represents the visible image is the | Body |
| The fuction of the blue tint added to the film's base is to | Enhance contrast |
| As kVp is decresed | Contrast increase |
| As kVp is incresed | Scale of contrast lengthens |
| Beam restriction has the folloing effect on contrast | Shorter scale of contrast |
| As Kvp increases, there is an incresed production of | Short wavelengths |
| The relationship between kVp and Density is | Direct, although not proportional |
| Grids that have strips angled to coincide with divergence of the x-ray beam are called | focused |
| The speed of the film-screen combination has what relationship with density | Direct, although not proportional |
| When a gird is used, what tech factor must be incresed to compensate for the loss of image-forming rays | mAs |
| Filters that even out density of irregular anatomy are called | compensating |
| Any misrepresentation of an anatomic structure on an image receptor that alters its size or shape defines | distortion |
| The speed of intensifying screens is expressed as a number that is called | Relative speed number |
| The density obtained with a 400- speed system is how many times that obtained with 100 speed system, for the same exposure | 4 |
| The wavelengh of light emitted by intensifying screen must be matched with wavelenghts to which the type of film used is most sensitive. This is called | Spectral matching |
| Grid ratio is expresses as | Heigh of the strip to the space between them |
| The primary type of the grid used in diagnostic imaging is | Focused |
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