Radiology Flashcards: Ch. 22-25
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Questions and Answers

What is rectangular collimation with F-speed film?

Rectangular collimation with digital sensor.

Which stage of the radiation injury sequence is your patient in if she reports having a burning sore throat and great difficulty swallowing?

  • Cumulative effects
  • Injury (correct)
  • Latent
  • Recovery

    • What could you tell your patient to alleviate her concerns about dental x-rays?

  • Your risk of getting cancer from dental x-rays is only 2 times greater than getting cancer spontaneously.
  • We take x-rays once a year, it is safe, and that is all your insurance will pay for.
  • The risks from dental imaging are not significantly greater than the risks of other everyday activities in modern life. (correct)
  • Three fourths of the radiation exposure you will have throughout your life will come from background radiation.

    • What are the ordered steps in the formation of hydrogen peroxide?

    <p>4, 2, 1, 3</p> Signup and view all the answers

    The gag reflex is elicited by stimulation of which sensitive tissues?

    <p>Soft palate</p> Signup and view all the answers

    The gag reflex is a(n) ___________ effort, preceded by ____________ of respiration.

    <p>involuntary; cessation</p> Signup and view all the answers

    Which receptor placement is most likely to elicit the gag reflex?

    <p>Maxillary molar</p> Signup and view all the answers

    What is the suggested receptor placement sequence for a patient who is likely to gag?

    <p>1, 2, 3</p> Signup and view all the answers

    What can you do to prevent stimulating your patient's gag reflex?

    <p>Put your finger on the tissue where the receptor will be placed to demonstrate the receptor placement.</p> Signup and view all the answers

    What should you do if your patient has a strong gag reflex and is gagging on maxillary anterior images?

    <p>Take a panoramic image to gather diagnostic information.</p> Signup and view all the answers

    If your patient starts gagging when you have just placed the receptor for the maxillary right molar, what should you do?

    <p>Take the receptor out of your patient's mouth as quickly as possible.</p> Signup and view all the answers

    What can be done to reduce the risk of a gag reflex?

    <p>Give your patient a cup of ice water to drink to reduce tactile stimuli.</p> Signup and view all the answers

    Which of the following suggestions are intended to help reduce the gag reflex?

    <p>Asking the patient to suspend an arm or leg in the air.</p> Signup and view all the answers

    When taking images on a patient with a hearing disability, you should wear your mask because of infection control guidelines.

    <p>False</p> Signup and view all the answers

    If a person is blind or visually impaired, how must the dental radiographer communicate?

    <p>Using clear verbal explanations.</p> Signup and view all the answers

    A developmental disability is a substantial impairment of mental or physical functioning that occurs before age ____ years and is of indefinite duration.

    <p>22</p> Signup and view all the answers

    In treating children with a primary or transitional dentition, the bisecting technique is preferred, because the small size of the mouth precludes the placement of a receptor beyond the apical regions of the teeth.

    <p>True</p> Signup and view all the answers

    ____________ periapical images can be used to examine the edentulous arches.

    <p>Fourteen</p> Signup and view all the answers

    A size ____ receptor is typically used for the edentulous examination.

    <p>2</p> Signup and view all the answers

    For a periapical examination in an edentulous patient, the receptor should be positioned so that approximately ____________ of it extends beyond the edentulous ridge.

    <p>one third</p> Signup and view all the answers

    What technique would you use for a periapical examination on an edentulous patient with very little alveolar ridge remaining?

    <p>Bisecting</p> Signup and view all the answers

    How many size 4 receptors and size 2 receptors does a mixed occlusal and periapical examination on an edentulous patient consist of?

    <p>two; four</p> Signup and view all the answers

    When preparing your patient for dental images, you should ask if she gags, need to do some additional preparation prior to taking the images.

    <p>False</p> Signup and view all the answers

    Advantages of panoramic receptors over intraoral periapical receptors include visualization of:

    <p>All of the above.</p> Signup and view all the answers

    A panoramic image is __________ image(s) taken using __________ technique.

    <p>a single; extraoral</p> Signup and view all the answers

    If the molars and premolars on the right side are larger than the teeth on the left side in a panoramic image, what patient positioning error did you make?

    <p>The patient's head was turned to the left.</p> Signup and view all the answers

    The panoramic image is the preferred image for the detection of caries and periodontal disease.

    <p>False</p> Signup and view all the answers

    In panoramic imaging, the x-ray tube rotates around the patient's head in one direction while the receptor rotates in the same direction.

    <p>False</p> Signup and view all the answers

    In panoramic imaging, the movement of the receptor and the tube head produces an image through the process known as:

    <p>Tomography</p> Signup and view all the answers

    What is the term for the pivotal point around which the cassette carrier and x-ray tube head rotate?

    <p>Rotation center</p> Signup and view all the answers

    The rotational change in a panoramic machine allows the image layer to conform to the ___________ shape of the dental arches.

    <p>elliptical</p> Signup and view all the answers

    In panoramic imaging, the ___________ is a theoretical concept used to determine where the dental arches must be positioned to achieve the clearest image.

    <p>focal trough</p> Signup and view all the answers

    Structures are clearly demonstrated on a panoramic image in a _____________ zone.

    <p>three-dimensional curved</p> Signup and view all the answers

    The closer the rotation center is to the teeth, the narrower the focal trough.

    <p>True</p> Signup and view all the answers

    All panoramic units have the same focal trough size and shape.

    <p>False</p> Signup and view all the answers

    Which component in the panoramic x-ray machine tubehead is most different from that found in an intraoral x-ray machine tubehead?

    <p>Collimator</p> Signup and view all the answers

    What is the function of the collimator used in the panoramic x-ray machine?

    <p>Restrict the size and shape of the x-ray beam.</p> Signup and view all the answers

    The collimator used in panoramic imaging has an opening in the shape of a _____________ slit.

    <p>Narrow vertical</p> Signup and view all the answers

    The vertical angulation in the tubehead of the panoramic unit:

    <p>Is fixed in position so that the x-ray beam is directed slightly upward.</p> Signup and view all the answers

    The tubehead of the panoramic unit always rotates _________ the patient's head as the receptor rotates _________ the patient.

    <p>Behind; in front of</p> Signup and view all the answers

    An anatomic structure that is located outside of the focal plane and close to the x-ray source can cast a ghost image on the panoramic image.

    <p>True</p> Signup and view all the answers

    Panoramic screen film is exposed by:

    <p>Intensifying screens in a cassette holder.</p> Signup and view all the answers

    Green-sensitive film must be paired with intensifying screens that produce ________ light.

    <p>green</p> Signup and view all the answers

    Rare earth screens emit _______ light and are considered faster than calcium tungstate screens, which emit _______ light.

    <p>green; blue</p> Signup and view all the answers

    A cassette has ________ intensifying screen(s).

    <p>Two</p> Signup and view all the answers

    You should have your 75-year-old patient remove her partial dentures and her hearing aids before taking a panoramic image because ghost images occur that could cover diagnostic information on the panoramic image.

    <p>True</p> Signup and view all the answers

    A ghost image appears ___________ than/of its actual counterpart.

    <p>higher</p> Signup and view all the answers

    What do you need to do to correct the error of having two radiopaque areas in the bottom portion of a panoramic image?

    <p>Use a lead apron without a thyroid collar.</p> Signup and view all the answers

    Digital imaging uses _________________ to produce an image.

    <p>An electronic sensor and computerized imaging system</p> Signup and view all the answers

    With digital imaging, the term ___________ is used to describe the pictures that are produced.

    <p>Image</p> Signup and view all the answers

    You explain to your patient that digital images require _________ exposure than the films she previously had taken. Exposure times are ________ than that required for conventional radiography.

    <p>50% to 90% less</p> Signup and view all the answers

    Most digital imaging systems use a ______________ as the x-radiation source.

    <p>Conventional dental x-ray unit</p> Signup and view all the answers

    In order to be used for digital imaging, the x-ray unit timer must be adapted to allow exposures in a time frame of _______ of a second.

    <p>1/100</p> Signup and view all the answers

    Digital sensors contain distinct units of programmable gray values that are sensitive to x-rays called

    <p>Pixels</p> Signup and view all the answers

    How many shades of gray can the human eye distinguish?

    <p>32</p> Signup and view all the answers

    (1) When you are preparing the sensor to use on your patient, it would be best to cover the sensor with a finger cot and then put on the barrier sleeve. (2) When you are placing the digital sensor in your patient's mouth, you would use a different placement technique than you would normally use when placing a film.

    <p>The first statement is true; the second statement is false</p> Signup and view all the answers

    Storage phosphor imaging

    <p>Uses a reusable imaging plate</p> Signup and view all the answers

    The images are cleared from the storage phosphor imaging plates by

    <p>A clearing step within the scanner</p> Signup and view all the answers

    Your patient has asked why you prefer digital imaging to film. Which of the following reasons would you tell her?

    <p>The image appears almost instantaneously for both of us to view</p> Signup and view all the answers

    (1) A primary advantage to digital imaging is the superior gray-scale resolution that results. (2) Digital imaging uses up to 32 shades of gray.

    <p>The first statement is true; the second statement is false</p> Signup and view all the answers

    Conventional dental x-ray film has a resolution of ___________ lp/mm.

    <p>12 to 20</p> Signup and view all the answers

    Sensors that cannot be sterilized

    <p>Require complete coverage with disposable plastic sleeves for each patient</p> Signup and view all the answers

    It is questionable whether digital images can be used as evidence in lawsuits, because

    <p>The original digital image can be enhanced</p> Signup and view all the answers

    (1) Given that the human eye can resolve 8 to 10 lp/mm, a CCD system is inadequate for diagnosis of dental disease. (2) The majority of research has shown that the traditional radiographs perform at least as well as digital images and, at times, even better.

    <p>Both statements are false</p> Signup and view all the answers

    Advantages of the use of digital imaging include which of the following?

    <p>There is an opportunity for an increase in interactive dialogue between the patient and the radiographer</p> Signup and view all the answers

    With the feature of _______________, the gray-scale of the diagnostic image is reversed so that radiolucent images appear white and radiopaque images appear black.

    <p>Digital subtraction</p> Signup and view all the answers

    Which of the following would be a reason to switch from film to direct digital imaging?

    <p>Digital images can be printed when needed</p> Signup and view all the answers

    A sensor with a fiber optic cable linked to the computer is placed into the mouth of the patient and exposed to x-radiation. This is an example of

    <p>Direct digital imaging</p> Signup and view all the answers

    How does the CMOS detector differ from the CCD detector?

    <p>The CMOS detector is silicon-based and differs from the CCD detector in the way that the pixels are read</p> Signup and view all the answers

    (1) All ionizing radiations cause damage to living tissues. (2) Although very little radiation is used in dentistry, damage to the cells does occur.

    <p>Both statements are true</p> Signup and view all the answers

    What specific mechanism of radiation injury may result in the formation of hydrogen peroxide when x-ray energy is absorbed by patients?

    <p>Free radical formation created by the ionization of water may occur</p> Signup and view all the answers

    Which of the following statements is true regarding the direct theory of radiation injury?

    <p>It involves damage to the critical areas of a cell through direct contact with the x-ray photon</p> Signup and view all the answers

    The indirect theory proposes that

    <p>Toxins are created from the formation of free radicals</p> Signup and view all the answers

    According to the dose-response curve, when dose and damage are plotted on a graph, a _____________________ relationship is seen.

    <p>Linear, nonthreshold</p> Signup and view all the answers

    A nonthreshold dose-response curve suggests that

    <p>Radiation exposure, no matter how small, causes damage to living tissue</p> Signup and view all the answers

    Stochastic biologic effects from radiation

    <p>Occur as a result of exposure, but severity is not determined by dose</p> Signup and view all the answers

    Which of the following is an example of stochastic effects?

    <p>Cancer</p> Signup and view all the answers

    Your patient was out in the hot, bright sun yesterday. While in the sun, she began experiencing pain and noticed her skin had turned bright red. Shortly after arriving home, she began to experience chills, nausea, severe pain, and blistering. Why would your patient experience the symptoms so quickly?

    <p>The latent period was decreased by the increased dose and dose rate</p> Signup and view all the answers

    Cellular injuries following the latent period may include (1) cell death, (2) cessation of mitotic activity, and/or (3) abnormal mitotic activity.

    <p>1, 2, 3</p> Signup and view all the answers

    ___________ refers to the total amount of radiation that is received or absorbed.

    <p>Total dose</p> Signup and view all the answers

    (1) More radiation damage takes place with high dose rates (2) because a rapid delivery of radiation does not allow time for cellular damage to be repaired.

    <p>Both statements are true</p> Signup and view all the answers

    Which types of cells are more sensitive to radiation: (1) rapidly dividing, (2) slowly dividing, (3) young, and/or (4) old?

    <p>1 and 3</p> Signup and view all the answers

    Which of the following is associated with long-term radiation effects?

    <p>Small amounts of radiation absorbed over a long period</p> Signup and view all the answers

    Which of the following is a sign or symptom of acute radiation syndrome (ARS)?

    <p>Hair loss</p> Signup and view all the answers

    Which of the following statements is true of somatic effects of irradiation?

    <p>Changes are not transmitted to future generations</p> Signup and view all the answers

    Which of the following cells would be the most sensitive to x-rays?

    <p>Blood</p> Signup and view all the answers

    Which of the following is the least sensitive to x-rays?

    <p>Salivary glands</p> Signup and view all the answers

    Precautions should be taken during dental imaging procedures to which of the following critical organs in the head and neck region?

    <p>1, 2, 3, 4</p> Signup and view all the answers

    The traditional unit of dose is called

    <p>The radiation absorbed dose (rad)</p> Signup and view all the answers

    One gray is equivalent to ______ rad(s).

    <p>100</p> Signup and view all the answers

    The SI equivalent of the rem is

    <p>The sievert</p> Signup and view all the answers

    You could be exposed to each of these radiation sources in your daily activities. Which of these sources is human-made?

    <p>Atomic fallout</p> Signup and view all the answers

    Uranium is an example of __________ radiation.

    <p>Terrestrial</p> Signup and view all the answers

    ________________ is/are the single largest contributor to artificial radiation exposure (0.00053 Sv/year).

    <p>Medical radiation</p> Signup and view all the answers

    Which of the following statements is true of the average dose of background radiation received by an individual in the United States?

    <p>Geographic areas at higher elevations are associated with increased amounts of cosmic radiation</p> Signup and view all the answers

    The potential risk of dental radiography inducing a fatal cancer in an individual is about _________ the risk of a person developing cancer spontaneously.

    <p>1/1000</p> Signup and view all the answers

    A 1 in 1 million risk of a fatal outcome is associated with which of the following activities?

    <p>All three of the above activities</p> Signup and view all the answers

    Risk estimates suggest (1) that death is more likely to occur from common activities than from dental imaging procedures and (2) that cancer is much more likely to be unrelated to dental imaging radiation exposure.

    <p>Both statements are true</p> Signup and view all the answers

    The use of F-speed film instead of D-speed film reduces the absorbed dose by ____%.

    <p>60</p> Signup and view all the answers

    Your patient is concerned about radiation exposure. Which of the following explanations would you give to your patient to help calm her concerns?

    <p>I am using this collimator attachment, which will decrease the x-ray dose you receive by 60-70%</p> Signup and view all the answers

    Study Notes

    Digital Imaging in Radiology

    • Digital imaging utilizes an electronic sensor and computerized imaging system to produce images.
    • The output from digital imaging is referred to as an "image" instead of traditional terms like radiograph or x-ray film.
    • Digital images require 50% to 90% less exposure compared to conventional film.

    Equipment and Technology

    • Most digital imaging systems operate using a conventional dental x-ray unit.
    • The x-ray unit timer must be adapted for exposures of at least 1/100 of a second for optimal use with digital sensors.
    • Digital sensors consist of pixels that capture and store gray values, optimizing image quality.

    Image Quality and Clinical Applications

    • The human eye can distinguish up to 32 shades of gray, providing limitations in detail perception.
    • Digital subtraction can reverse gray-scale images, ensuring radiolucent areas appear white and radiopaque areas appear black.
    • Direct digital imaging employs a CCD camera where a sensor links fiber optic cables to a computer for immediate image capture.

    Radiation Safety and Exposure

    • Ionizing radiation can damage living tissues; all forms of radiation, including those used in dentistry, pose some risks.
    • Stochastic effects of radiation, such as cancer, are related to exposure without a dose threshold, indicating that any level can be harmful.
    • The potential risk of inducing fatal cancer from dental radiography is around 1 in 1,000.

    Radiobiology Principles

    • Damage from radiation can occur through direct contact or through free radical formation, especially when water molecules are ionized.
    • There is a distinction between somatic effects (not inherited) and genetic effects (transmitted generations).
    • Cells that divide rapidly, such as blood cells, are more sensitive to radiation exposure than those that divide slowly.
    • Precautions during dental imaging procedures target sensitive areas like the skin, thyroid gland, and lens of the eye to minimize exposure risks.
    • The original digital images can be enhanced, which raises concerns about their admissibility as legal evidence compared to traditional film.

    Clinical Best Practices

    • Using F-speed film reduces radiation exposure by approximately 60% compared to D-speed film.
    • Rectangular collimation combined with a digital sensor provides the lowest absorbed dose during dental radiographs.
    • Medical radiation represents the most significant source of artificial radiation exposure annually.

    Patient Communication and Education

    • It's essential to communicate clearly with patients about the necessity, safety, and minimized exposure associated with digital imaging techniques.
    • Educating patients about the comparative risks of dental imaging versus everyday activities can alleviate concerns about radiation exposure.### Maxillary Molars and Gag Reflex Management
    • Maxillary molars are key teeth in dentistry, often involved in procedures requiring specific receptor placements.
    • The suggested sequence for receptor placement to minimize gag reflex is anterior, premolar, then molar (1, 2, 3).
    • To prevent gagging during receptor placement, techniques include letting the patient feel the receptor placement with a finger.

    Gag Reflex Strategies

    • In cases where patients have a strong gag reflex and struggle with maxillary anterior images, taking panoramic images can provide diagnostic information while avoiding gagging.
    • If a patient begins to gag while exposing a maxillary right molar receptor, it is best to remove the receptor quickly.
    • Offering a cup of ice water may help reduce tactile stimuli, which could trigger a gag reflex.

    Patient Interaction and Disabilities

    • Effective communication is essential for patients with sensory impairments; verbal explanations are needed for those who are blind or visually impaired.
    • Developmental disabilities involve significant impairment occurring before the age of 22.
    • In treating children with limited mouth space, the bisecting technique is preferred for receptor placement.

    Edentulous Imaging Techniques

    • Fourteen periapical images can assess edentulous arches, usually utilizing size 2 receptors.
    • For periapical examinations in edentulous patients with minimal alveolar ridge, the bisecting technique is the recommended approach.
    • A mixed examination of edentulous patients involves two size 4 receptors and four size 2 receptors.

    Panoramic Imaging Advantages

    • Panoramic imaging is better for visualizing impacted teeth, jaw fractures, and large lesions in comparison to intraoral periapical receptors.
    • The panoramic image is captured as a single extraoral image, while the x-ray tube rotates in one direction, and the receptor rotates in the opposite direction.

    Technical Aspects of Panoramic Imaging

    • The rotation center defines the axis around which imaging components rotate, creating an elliptical focal trough that aids in achieving clearer images.
    • The concept of a focal trough determines where dental arches should be positioned for optimal imaging clarity.

    Collimator Function and Parameters

    • Panoramic collimators have a narrow vertical opening to restrict the x-ray beam size and shape, differentiating them from intraoral designs.
    • Vertical angulation is fixed to direct the x-ray beam slightly upward, ensuring proper angles for capturing images.
    • Ghost images can appear due to structures outside the focal plane, affecting the clarity of the resulting panoramic images.

    Film and Screen Information

    • The exposure of panoramic screen film is facilitated by intensifying screens within cassette holders.
    • Green-sensitive film requires compatibility with green-emitting screens, while rare earth screens are faster than calcium tungstate screens due to their light emissions.

    Handling and Preparation for Panoramic Imaging

    • Ghost images from partial dentures or hearing aids may obscure diagnostic data; patients should remove these items before imaging.
    • A lead apron used without a thyroid collar can help mitigate ghost imaging errors.

    Common Errors and Solutions

    • The presence of two radi opaque areas in a panoramic image may necessitate the use of a different type of lead apron.
    • Proper patient positioning is critical; turning the head inaccurately can result in asymmetrical tooth sizes in the final image.

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    Test your knowledge of radiology concepts with these flashcards covering Chapters 22 to 25. Each card presents a question related to digital imaging technology and its applications. Perfect for students of radiology looking to enhance their understanding of the subject.

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