Principles of Radiography 1
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Questions and Answers

Which of the following are patient/subject factors that affect radiographic technique? (Select all that apply)

  • Image Quality Factors
  • Tissue Mass Density (correct)
  • Effective Atomic Number (correct)
  • Patient Thickness (correct)

    • What is subject contrast?

    The degree of differential absorption resulting from the differing absorption characteristics of the tissues in the body.

    What body type is described as having a large frame and being overweight?

    Hypersthenic

    Define attenuation in the context of radiography.

    <p>The reduction in the total number of x-ray photons remaining in the beam after passing through a given thickness of material.</p> Signup and view all the answers

    Which of the following conditions are considered additive pathologies? (Select all that apply)

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

    What type of pathology requires decreasing the mAs during radiographic procedures?

    <p>Destructive pathology</p> Signup and view all the answers

    The basic photometric unit is the ______.

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

    True or False: A patient history is irrelevant in determining radiographic technique adjustment.

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

    What happens to the luminous intensity when viewed from the side?

    <p>It decreases.</p> Signup and view all the answers

    What is the relationship between bore obstruction and radiographic technique?

    <p>Bowel obstruction requires a decrease in technique.</p> Signup and view all the answers

    What has led to reconfigured ergonomic digital workstations for Radiographers and Radiologists?

    <p>The viewing requirements of flat panel digital display devices.</p> Signup and view all the answers

    Ambient light levels should be increased for the best viewing of digital display devices.

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

    What is the purpose of calibrating digital equipment?

    <p>To recognize dead pixels and 'auto-fill' the areas.</p> Signup and view all the answers

    Flatfielding is performed during ______ to offset the irregular variation of the anode-heel effect.

    <p>pre-processing</p> Signup and view all the answers

    What technique is used to correct defective pixels in digital IRs?

    <p>Signal Interpolation</p> Signup and view all the answers

    What is image lag?

    <p>Image that is not completely visible and is corrected by applying offset voltage.</p> Signup and view all the answers

    Which of the following is NOT a post-processing action?

    <p>Direct Exposure</p> Signup and view all the answers

    Image inversion results in a black appearance of soft tissue and a white appearance of bone.

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

    How many shades of gray does a 16-bit dynamic range DR system have?

    <p>65,536</p> Signup and view all the answers

    Image subtraction is commonly used in ______.

    <p>Digital Subtraction Angiography (DSA)</p> Signup and view all the answers

    What does pixel shift allow for in image processing?

    <p>Correction of patient motion in a series of images.</p> Signup and view all the answers

    Which adjustment impacts the visibility of detail in an image?

    <p>Window Width</p> Signup and view all the answers

    What is the effect of increasing window level in image processing?

    <p>Increase density (brightness)</p> Signup and view all the answers

    What is the primary effect of destructive pathologies on x-ray beam attenuation?

    <p>Decreased attenuation of the x-ray beam</p> Signup and view all the answers

    When managing a patient with increased destructive pathology, how should the mAs be adjusted?

    <p>Decreased by 25-50%</p> Signup and view all the answers

    Which of the following conditions is classified under additive pathologies?

    <p>Aortic Aneurysm</p> Signup and view all the answers

    What is the relationship between destructive pathology and IR exposure?

    <p>Directly proportional</p> Signup and view all the answers

    Which statement is true regarding effective techniques for imaging patients with chronic destructive pathologies?

    <p>Use standard kVp with reduced mAs</p> Signup and view all the answers

    What is the primary factor influencing spatial resolution in digital radiography?

    <p>The size of the pixels involved</p> Signup and view all the answers

    Which condition would most likely require an increase in radiographic technique due to fluid presence?

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

    In the context of imaging pathologies, which of the following describes a condition that does not significantly alter radiographic density?

    <p>Fractures without gross swelling</p> Signup and view all the answers

    What anatomical feature is most effectively visualized with long-scale contrast adjustments?

    <p>Lung processes</p> Signup and view all the answers

    Which of the following statements about radiographic quality is true?

    <p>Multiple factors influence the fidelity of the anatomical imaging.</p> Signup and view all the answers

    Which of the following pathologies is considered a destructive pathology affecting bone density?

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

    What is the minimum percentage of bone loss required before changes can be detected on a radiograph?

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

    Which of the following best defines the term 'image quality' in radiography?

    <p>The clarity of the anatomical structure being imaged</p> Signup and view all the answers

    What defines the portion of the pixel face available for transmitting light on an LCD monitor?

    <p>Aperture Ratio</p> Signup and view all the answers

    What is the primary disadvantage of an LCD monitor when viewing images at an angle?

    <p>Loss of image contrast</p> Signup and view all the answers

    What is contrast resolution primarily used for in radiography?

    <p>To differentiate between anatomical structures of similar subject contrast</p> Signup and view all the answers

    Which mechanism continues to emit light after the initial stimulation of a phosphor?

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

    How is distortion minimized in radiographic imaging?

    <p>By keeping the patient's body part parallel to the image receptor</p> Signup and view all the answers

    Among the following, which light emission process occurs alongside the flow of electrons in materials?

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

    What term describes the degree of sharpness of structural lines on a radiograph?

    <p>Recorded Detail</p> Signup and view all the answers

    What is a significant advantage of LED monitors over fluorescent backlit monitors?

    <p>Lower energy consumption</p> Signup and view all the answers

    What condition is considered optimal for the viewing of images on LCD monitors?

    <p>Dim ambient light</p> Signup and view all the answers

    What is the primary concern when interpreting medical images in terms of visibility of detail?

    <p>Optimization of contrast and optical density</p> Signup and view all the answers

    What is the effect of foreshortening in radiographic imaging?

    <p>Objects appear shorter than their actual length</p> Signup and view all the answers

    How does the brightness requirement for a white image with black text compare to one with white text on a black background in LED displays?

    <p>It requires more power</p> Signup and view all the answers

    What is the role of photometry in digital imaging?

    <p>To measure the response of the human eye to visible light</p> Signup and view all the answers

    What is the main benefit of reducing ambient light levels for LCD monitors?

    <p>Improves image contrast</p> Signup and view all the answers

    What is the term for the misrepresentation of true size or shape in imaging?

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

    What distinguishes photopic vision from scotopic vision in the context of radiographic interpretation?

    <p>Photopic vision uses cone cells in bright light while scotopic vision uses rod cells in dim light</p> Signup and view all the answers

    Which of the following correctly describes image inversion in digital imaging?

    <p>It allows for improved visibility of pathology by reversing color contrasts.</p> Signup and view all the answers

    When would pixel shift be primarily used in digital imaging?

    <p>To correct for misalignment in the patient's position during imaging.</p> Signup and view all the answers

    What is the primary purpose of region of interest (ROI) in digital imaging?

    <p>To select specific areas for detailed analysis and rescaling.</p> Signup and view all the answers

    What is the primary function of pre-processing in digital imaging?

    <p>To ensure images are artifact-free before display</p> Signup and view all the answers

    What is the role of edge enhancement in post-processing of images?

    <p>To clarify and highlight regions with fractures and small high-contrast tissues.</p> Signup and view all the answers

    In what scenario would image subtraction be most beneficial?

    <p>In Digital Subtraction Angiography (DSA) to highlight blood vessels.</p> Signup and view all the answers

    Which process involves repairing dead pixels by assigning digital values from surrounding pixels?

    <p>Signal Interpolation</p> Signup and view all the answers

    What type of image correction is applied to address the irregular variation caused by the anode-heel effect?

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

    How frequently are gain images generated in the calibration of digital equipment?

    <p>Every few months</p> Signup and view all the answers

    Which issue is corrected by applying offset voltage before acquiring the next image?

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

    What technique is used to address line noise in digital imaging?

    <p>Offset Correction from Dark Reference Zone</p> Signup and view all the answers

    What is the role of automatic calibration images like offset images?

    <p>To make IR response more uniform</p> Signup and view all the answers

    Which of the following best describes the action of interoperability between adjacent pixels?

    <p>Signal Interpolation</p> Signup and view all the answers

    What adjustment should be made to kVp when dealing with additive pathology?

    <p>Increase kVp by 5-15%</p> Signup and view all the answers

    How does additive pathology affect IR exposure?

    <p>It reduces IR exposure.</p> Signup and view all the answers

    What is the relationship between additive pathology and technical factors in radiography?

    <p>Additive pathology requires adjusted technical factors for effective imaging.</p> Signup and view all the answers

    What does an increase of 15% in kVp achieve in terms of exposure to the IR?

    <p>It doubles the exposure to the IR.</p> Signup and view all the answers

    What is an indicator of the presence of additive pathology in a patient?

    <p>An increase in external anatomical deviations.</p> Signup and view all the answers

    What impact does patient thickness have on x-ray attenuation?

    <p>Thicker body sections absorb more x-rays than thinner sections.</p> Signup and view all the answers

    Which body type would most likely require special considerations due to its physical characteristics?

    <p>Hypersthenic: It is large and overweight.</p> Signup and view all the answers

    How does subject contrast influence radiographic quality?

    <p>Higher subject contrast improves radiographic detail.</p> Signup and view all the answers

    In what way does effective atomic number affect radiographic contrast?

    <p>Higher effective atomic numbers increase the differential absorption.</p> Signup and view all the answers

    What is a consequence of inadequate adjustment of exposure techniques based on patient characteristics?

    <p>Image quality may suffer, leading to diagnostic challenges.</p> Signup and view all the answers

    Which factor is directly proportional to the number of x-rays leaving a body section?

    <p>Patient density.</p> Signup and view all the answers

    What does the term 'attenuation' specifically refer to in medical imaging?

    <p>The interaction of x-rays with matter leading to absorption or scattering.</p> Signup and view all the answers

    Which aspect of patient characteristics requires consideration in radiographic technique but does not relate to geometric factors?

    <p>Effective atomic number.</p> Signup and view all the answers

    Which condition requires an adjustment to the radiographic technique due to the presence of liquid in the abdomen?

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

    What is a common outcome for imaging a skeletal structure affected by osteoporosis?

    <p>50% bone loss before visibility</p> Signup and view all the answers

    Which of the following statements correctly describes the factors that influence image quality?

    <p>Spatial resolution is limited by pixel size in digital radiography</p> Signup and view all the answers

    In radiographic imaging, which condition is classified as an additive pathology?

    <p>Multiple Myeloma</p> Signup and view all the answers

    Which tissue has the highest effective atomic number?

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

    What defines a high-quality radiograph?

    <p>Ability to visualize anatomic structures accurately</p> Signup and view all the answers

    Which condition signifies the need to decrease the radiographic technique due to higher air levels in the GI tract?

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

    How does emphysema typically affect tissue composition in radiographic imaging?

    <p>Decreased mass density of lung tissue</p> Signup and view all the answers

    Which contrast material has the lowest effective atomic number?

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

    How does chronic destructive pathology primarily affect x-ray beam attenuation?

    <p>Decreases the overall density</p> Signup and view all the answers

    Observing physical indications of pathology during patient assessment helps in which key area of radiography?

    <p>Preventing unnecessary repeat radiographs</p> Signup and view all the answers

    In terms of spatial resolution, what is a critical factor in digital imaging?

    <p>Pixel size</p> Signup and view all the answers

    What does visibility of detail in radiographic imaging primarily depend on?

    <p>Contrast resolution and optical density</p> Signup and view all the answers

    Which of the following pathologies is associated with a decrease in tissue thickness?

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

    How can foreshortening affect the representation of anatomical structures in imaging?

    <p>It causes structures to appear shorter than their actual length.</p> Signup and view all the answers

    What type of tissues absorb x-rays and appear white on a radiograph?

    <p>Radiopaque tissue</p> Signup and view all the answers

    Which of the following best describes the effect of dense pathologies on radiographic images?

    <p>Decreased visibility of structures</p> Signup and view all the answers

    What defines the term 'distortion' in radiographic imagery?

    <p>An error in representing true size or shape of an object.</p> Signup and view all the answers

    Which practice helps to reduce distortion in radiographic imaging?

    <p>Positioning the image receptor parallel to the central ray</p> Signup and view all the answers

    What is a potential impact of reviewing patient history before imaging?

    <p>Provides clues about potential pathology</p> Signup and view all the answers

    What element differentiates photopic vision from scotopic vision?

    <p>The roles of cones and rods under different lighting conditions.</p> Signup and view all the answers

    What is meant by the term 'contrast resolution' in radiography?

    <p>The ability to distinguish between tissues with similar densities.</p> Signup and view all the answers

    Which process quantifies light perception in human vision, established by the CIE?

    <p>Quantification of illumination through footcandles</p> Signup and view all the answers

    What is the primary purpose of calibration in the digital imaging system?

    <p>To identify and auto-fill dead pixels</p> Signup and view all the answers

    What is a significant challenge in imaging that can lead to shape distortion?

    <p>Misalignment of the central ray with the body part</p> Signup and view all the answers

    Which technique is employed to repair dead pixels in digital images before processing?

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

    How often are gain images generated in the calibration process?

    <p>Every few months</p> Signup and view all the answers

    What is the primary function of flatfielding in digital image pre-processing?

    <p>To offset irregular variations</p> Signup and view all the answers

    What does signal interpolation primarily correct for in digital imaging?

    <p>Defective pixels</p> Signup and view all the answers

    What does the term 'image lag' refer to in the context of digital imaging?

    <p>Incomplete visibility of an electronic latent image</p> Signup and view all the answers

    Which of the following best illustrates a pre-processing step in digital imaging?

    <p>Repairing dead pixel areas before processing</p> Signup and view all the answers

    What type of correction is applied to address line noise in digital imaging?

    <p>Dark reference zone correction</p> Signup and view all the answers

    Study Notes

    Principles of Radiography 1: Patient-Image Optimization & Viewing the Medical Image

    • Julie Kloft, MSRS, RT(R), Clinical Coordinator & Professor of Radiography
    • The presentation covers patient/subject factors, image-quality factors, and exposure technique factors relevant to optimizing radiographic images.

    Patient/Subject Factors

    • Subject Contrast: The degree of differential absorption resulting from tissue differences in the body.
    • Patient Thickness: Denser objects absorb more radiation.
    • Tissue Mass Density: Different patients with equal thickness can have varying mass densities.
    • Effective Atomic Number: This varies greatly among tissues, significantly impacting subject contrast. Materials/substances and their effective atomic number are listed.
    • Object Shape: Technique adjustments compensate for patient size, shape, and composition. Positioning is related to geometric factors.

    Image-Quality Factors

    • Spatial Resolution: Ability to image small objects with high contrast (e.g., bone and soft tissue).
    • Contrast Resolution: Ability to distinguish structures with similar subject contrast (e.g., liver and spleen).
    • Distortion: Misrepresentation of true object size or shape on the radiograph. Foreshortening (shorter than actual length) and elongation (longer than actual length) are types of shape distortion. Magnification can distort size. Distortion reduced by proper positioning (body part parallel to IR and Central Ray perpendicular to both).
    • IR Response: The display device's response to the incoming light depends on photometry (the science of human eye response to light).

    Pathology

    • Pathology can affect tissue thickness/composition, altering effective atomic number (or density). This changes x-ray attenuation.
      • Additive conditions increase attenuation, and require increased kVp. Examples include Effusion, Hydrocephalus, and more.
      • Destructive conditions decrease attenuation, and require a decrease of mAs. Examples include Osteoporosis, Emphysema, and other conditions.
    • Collecting patient history and observing physical characteristics is important to avoid repeat radiographs.

    Viewing the Medical Image

    • The science of photometry is important when using digital imaging and viewing technologies (Digital Imaging devices).
    • Photometric quantities: Lumen, luminous flux, candlepower, etc.
    • Understanding eye response (photopic and scotopic vision) is important for effective image viewing and analysis.

    Image Display

    • Luminance: The measurement of source brightness in candela per sq meter or nit. Luminance intensity measures the luminous flux emitted into the entire viewing area.
    • Cosine Law explains how intensity of light is reduced from the side on LCDs. LCD monitors should be examined straight-on so intensity and contrast are maximized.
    • Inverse Square Law – Luminance intensity decreases as the square of the distance from the light source increases.

    Digital Imaging Considerations

    • Artifacts such as dead pixels are addressed by pre-processing methods. Calibration is used to identify and correct these issues.
    • Pre-processing methods correct for image lag, line noise and other issues in digital images.
    • Flatfielding corrects for anode-heel effect.
    • Signal interpolation corrects defective pixels by averaging the response of surrounding pixels.

    Post-Processing

    • Window/Leveling allows visualization of a broader range of gray scales.
    • Image Annotation adds labels, patient info, and other data to the image.
    • Image Inversion changes the appearance of the image (white and black areas swap to improve visibility).
    • Magnification is performed by using the larger matrix size to improve spatial resolution of small anatomical portions of the image.
    • Image Flip reorients the image.
    • Pixel Shift adjusts for patient movement.
    • Additional post-processing features include edge enhancement, highlighting, and zooming for detailed analysis.

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    Patient Image Optimization & Viewing the Medical Image PDF

    Description

    This quiz delves into the critical aspects of patient-image optimization in radiography. Covering patient factors such as tissue density and subject contrast, as well as image-quality factors like spatial resolution, this assessment is essential for those in the medical imaging field.

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