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Questions and Answers
What does kVp stand for in radiography?
What does kVp stand for in radiography?
High kVp results in low photon energy and high contrast in a radiograph.
High kVp results in low photon energy and high contrast in a radiograph.
False
What is radiographic contrast?
What is radiographic contrast?
The density difference between two adjacent areas on a radiographic image.
A radiograph with a _______ gray scale exhibits predominantly black and white tones.
A radiograph with a _______ gray scale exhibits predominantly black and white tones.
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Which of the following factors influences radiographic contrast?
Which of the following factors influences radiographic contrast?
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Match the following types of contrast with their descriptions:
Match the following types of contrast with their descriptions:
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Subject contrast is influenced by the individual patient’s tissues and body condition.
Subject contrast is influenced by the individual patient’s tissues and body condition.
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What happens to the penetrating power of the beam when kVp is increased?
What happens to the penetrating power of the beam when kVp is increased?
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What is the primary advantage of MRI over other imaging modalities?
What is the primary advantage of MRI over other imaging modalities?
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Radiation safety protocols are important during CT examinations.
Radiation safety protocols are important during CT examinations.
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What is the purpose of a scout image made prior to a CT examination?
What is the purpose of a scout image made prior to a CT examination?
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The large main magnet used in MRI is typically a ________ magnet.
The large main magnet used in MRI is typically a ________ magnet.
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Match the following components of MRI with their functions:
Match the following components of MRI with their functions:
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What temperature must a superconducting magnet be maintained at to function properly?
What temperature must a superconducting magnet be maintained at to function properly?
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Patients are advised to be left unattended in the CT room during scanning.
Patients are advised to be left unattended in the CT room during scanning.
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What happens to protons in the patient during the MRI process when a radiofrequency wave is applied?
What happens to protons in the patient during the MRI process when a radiofrequency wave is applied?
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What is a radionuclide?
What is a radionuclide?
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The half-life of a radionuclide refers to the time it takes for all the radioactive atoms to decay.
The half-life of a radionuclide refers to the time it takes for all the radioactive atoms to decay.
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What imaging procedure uses radiopharmaceuticals to diagnose abnormal function?
What imaging procedure uses radiopharmaceuticals to diagnose abnormal function?
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The most commonly used radionuclide is __________.
The most commonly used radionuclide is __________.
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What is the primary purpose of a gamma camera?
What is the primary purpose of a gamma camera?
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Match the following terms with their definitions:
Match the following terms with their definitions:
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Radionuclides emit particles and energy in a predictable manner.
Radionuclides emit particles and energy in a predictable manner.
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Gamma rays are measured in __________.
Gamma rays are measured in __________.
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What is the minimum potential difference required for X-ray generation?
What is the minimum potential difference required for X-ray generation?
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The kinetic energy of electrons in X-ray production is completely transformed into X-ray photons.
The kinetic energy of electrons in X-ray production is completely transformed into X-ray photons.
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What is the main limiting factor of X-ray production?
What is the main limiting factor of X-ray production?
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The target material used in X-ray machines is _____ due to its high melting point.
The target material used in X-ray machines is _____ due to its high melting point.
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Match the following components of an X-ray apparatus with their functions:
Match the following components of an X-ray apparatus with their functions:
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What percentage of the energy is typically converted to heat during X-ray production?
What percentage of the energy is typically converted to heat during X-ray production?
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Smaller focal spots in X-ray machines are preferable for better imaging quality.
Smaller focal spots in X-ray machines are preferable for better imaging quality.
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Primary radiation is defined as radiation that _____ without interaction with matter.
Primary radiation is defined as radiation that _____ without interaction with matter.
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What is the formula for calculating kVp for abdominal radiographs?
What is the formula for calculating kVp for abdominal radiographs?
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Increasing the kV can improve image quality by increasing penetration.
Increasing the kV can improve image quality by increasing penetration.
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What does mAs control in radiographic imaging?
What does mAs control in radiographic imaging?
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The kV selected should be the optimum kV for the ______ being examined.
The kV selected should be the optimum kV for the ______ being examined.
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Match the following concepts with their definitions:
Match the following concepts with their definitions:
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Which of the following is true about wide exposure latitude?
Which of the following is true about wide exposure latitude?
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Using excessive kV levels can improve the quality of a radiograph.
Using excessive kV levels can improve the quality of a radiograph.
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What indicates a narrow exposure latitude?
What indicates a narrow exposure latitude?
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Study Notes
X-Ray Production and Properties
- The kinetic energy of electrons in an X-ray tube is proportional to the potential difference between the anode and cathode.
- This potential difference is measured in kilovolts (kV) or kilovoltage peak (kVp), which indicates the maximum available energy at that kV setting.
- kVp determines the quality of the x-ray beam and its ability to penetrate tissue.
- Higher kVp results in shorter wavelength x-rays with greater penetrating power.
- Higher kVp decreases image contrast (long gray scale).
- Lower kVp results in longer wavelength x-rays with less penetrating power.
- Lower kVp increases image contrast (short gray scale).
Radiographic Contrast
- Radiographic contrast refers to the density difference between adjacent areas on a radiographic image.
- Desired contrast varies depending on the anatomic area being imaged.
- Subject contrast, kVp level, and scatter radiation influence radiographic contrast.
Subject Contrast
- Subject contrast is the degree of differential absorption due to differing absorption characteristics of different tissue types.
- It is dependent on the specific characteristics of an individual patient's tissues, including disease, age, and body condition.
Exposure Factors
- mAs controls beam intensity and image resolution.
- kV controls contrast and affects image quality.
- Optimum kV is the kV that penetrates the body part, produces sufficient contrast, and minimizes scatter radiation.
Exposure Latitude
- Exposure latitude is the range of acceptable mAs values for producing diagnostic images.
- Narrow exposure latitude is associated with low kV and high contrast.
- Wide exposure latitude is associated with high kV and low contrast.
X-ray Beam
- The x-ray beam leaving the tube-housing is called the primary beam.
- Primary radiation is radiation from the tube without interaction with matter.
- Santè's rule can be used to estimate kVp:
- Abdomen: kV = (2 x cm [body part thickness]) + 30
- Bone: kV = (2 x cm [body part thickness]) + 40
- Thorax: kV = (2 x cm [body part thickness]) + 70
mAs and kV Relationship
- Increased penetration of the beam due to high kV produces a more intense remnant beam, similar to an increase in mAs.
- Excessive kV levels can overexpose and decrease contrast, resulting in poor image quality.
Focal Spot
- The electrons in an X-ray tube are focused into a thin stream by the focusing cup and strike a small area of the target called the focal spot.
- A smaller focal spot size improves image sharpness.
X-ray Production Process
- When electrons strike the target, they lose kinetic energy and produce x-ray photons (1%) and heat (99%).
- The target is made of tungsten due to its high melting point, which allows it to withstand the heat produced.
- Rotating anodes help dissipate heat by rotating the target and exposing different areas to electron bombardment.
Radiopharmaceuticals
- Radiopharmaceuticals contain radionuclides within their chemical structure for diagnosis or treatment.
- They deliver the radionuclide to specific organs.
Scintigraphy
- Scintigraphy uses radiopharmaceuticals to diagnose abnormal function by detecting gamma rays emitted by the radiopharmaceutical.
Technetium-99m
- Technetium-99m is a widely used radionuclide due to its short half-life, easily detectable gamma rays, and ability to bind to various compounds.
Gamma Camera
- A gamma camera contains a collimator, detector, positional circuitry, counter, and recording device.
- It detects and measures gamma rays emitted by the radiopharmaceutical, creating an image.
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Description
Test your knowledge on the principles of X-ray production and the properties that affect radiographic contrast. This quiz covers the role of kilovoltage in determining image quality and the impact of subject and scatter radiation on contrast. Perfect for students in radiology or medical imaging courses!
