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Final exam Review
Quiz 38
| Question | Answer |
|---|---|
| The time lapse from x-ray exposure until noticeable damage occurs is known as | the latent period. |
| Which of the following is the basic form of matter? | An atom |
| Secondary radiation | refers to x-radiation that is created when the primary beam interacts with matter. |
| All the following are true of electromagnetic radiation except they | contain radioactive substances such as uranium. |
| The Guidelines for Prescribing Dental Radiographs issued by the American Dental Association and the FDA recommend which of the following dental imaging procedures for a pregnant patient? | Radiographic imaging procedures do not need to be altered because of pregnancy. |
| A lead apron and a thyroid collar | must be used on all patients for all exposures. |
| All the following are true statements about film badges except | they should be worn when any form of x-ray is taken. |
| If you change the exposure time of the x-ray unit, what is affected? | Number of x-rays produced |
| A good technique for reducing the radiation exposure to both patient and operator is the use of | fast film or digital imaging. |
| Chronic radiation exposure occurs when _____ doses of radiation are received over a _______ time period. | small; long |
| A step-down transformer is necessary within the x-ray circuitry to | boil off electrons from the filament. |
| An exposure time of 1/4 second is equal to _____ impulse(s). | 15 |
| If a patient is small and petite, to get the same density radiograph it is best to reduce the | exposure time and mA. |
| Dental imaging | refers to film-based images. refers to digitally produced images. detects conditions that might otherwise remain undetected. is all of the above. |
| What is the purpose of the insulating oil that fills the x-ray machine housing and surrounds the x-ray tube? | Absorbs heat created by the production of x-rays. |
| When the master switch is on | the electron cloud is created around the tungsten filament. |
| The heart of the x-ray generating system is the | x-ray tube. |
| When the electrons strike the target, ____________________ are generated. | 99% heat and 1% x-rays |
| The dentist says that the image has too much contrast; she would like to see more gray values. What adjustment would you make? | Increase kVp. |
| One of the rules of radiation protection is never stand closer than ______ feet from the x-ray unit during an exposure unless you are behind a barrier. | 6 |
| The range of shades of gray between black and white on an image is called | contrast. |
| How much filtration is federally required for a dental x-ray machine operating over 70 kVp? | 2.50 mm |
| The function of the _________ filter in the x-ray tube is to ____________________. | aluminum; remove long wavelengths from the beam |
| What happens when the exposure button is engaged? | The high-voltage circuit is activated. Kilovolts drive the electrons to the target. Electrons slam against the target producing the x-ray. All of the above are correct. |
| The component of the x-ray machine that functions in positioning the tubehead is the | extension arm. |
| The maximum permissible dose for an occupational worker for an individual 18 years of age or older is _____ rem/year. | 5 |
| The x-ray was discovered in 1895 by | Wilhelm Conrad Roentgen. |
| The degree of density or blackness on an image is controlled by the | milliampere seconds |
| In dentistry, the __________ the wavelengths of the x-rays, the greater their energy and their usefulness. | shorter |
| A radiograph that has an overall gray appearance is generally preferred. This radiograph is said to have | low contrast. |
| How well the image reproduces fine detail or distinct outlines of an object is called | sharpness. |
| The portion of the x-ray machine that supplies the electrons to produce x-rays is the | cathode. |
| f the operator’s film badge indicates an exposure to small amounts of radiation, what should be done? | Evaluate the x-ray equipment and techniques. |
| When in storage, the lead apron should be | Both A and C. |
| The location where x-rays are produced in the x-ray tube is called the | focal spot. |
| Primary radiation is | also called the useful beam. the beam of x-rays that comes from the target. Both A and B. |
| The term ____________ is used to describe areas that appear dark on the image; ___________ is the term used to describe areas that appear white or light gray. | radiolucent; radiopaque |
| An example of cumulative radiation exposure is | cataracts. leukemia. cancer. All of the above. |
| The uses of dental images include the detection of | abnormalities in surrounding hard and soft tissues. |
| Because the entire x-ray area is considered a radiation hazard area, a radiation hazard sign must be posted in | sight of patients. sight of personnel. Both A and B. |
| The lead collimator is used to | restrict the size and shape of the primary beam. |
| Which of the following terms is used to describe the energy or penetrating ability of the x-ray beam in dental radiography? | Quality |
| The fuzzy or blurred area around an image is called _____________. It can be reduced by _______________. | a penumbra; limiting movement |
| Which of the following is the name for the primary kind of radiation produced in the dental x-ray tubehead? | Braking radiation |
| The dentist who is credited making the first dental radiograph in 1895 is | Otto Walkhoff. |
| All of the following structures will appear radiolucent on dental x-ray film except | metal restorations. |
| Who should hold the film in a patient’s mouth if the patient is unable to do so? | Parent or relative of the patient |
| Thermionic emission refers to the | release of electrons from the tungsten filament. |
| A patient is concerned with radiation exposure. You can assure him that your office uses the ALARA concept, which includes | reducing the number of exposures. minimizing retakes. keeping exposures levels as low as possible. All of the above. |
| One of the earliest signs of overexposure to x-rays may be | erythema. |
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alejac0360