CT Registry Review Hh
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On a multi-row detector scanner, radiation penumbra may be found:
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On every other slice
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Only on the trailing edges of the slices
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On every slice
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Only on the first and last slices of the slice volume
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The 'CT Registry Review HH' quiz assesses knowledge on CT scanner technicalities, normal physiological parameters like blood pressure and pulse rates, and radiation safety. It is designed for medical professionals preparing for CT registry certification.
Quiz Preview
- 2.
What is normal blood presure values for adult systolic
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90-140
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75-90
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80-110
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70-100
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60-90
Correct Answer
A. 90-140Explanation
The normal blood pressure values for adult systolic range from 90 to 140. This means that a healthy adult should have a systolic blood pressure reading between these two numbers. Systolic blood pressure is the top number in a blood pressure reading and represents the pressure in the arteries when the heart beats and pumps blood. A reading within this range indicates that the heart is functioning properly and is able to pump blood effectively throughout the body.Rate this question:
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- 3.
What is the normal blood presure values for adults diastolic
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60-90
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70-85
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85-100
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75-90
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50-75
Correct Answer
A. 60-90Explanation
The normal blood pressure values for adults diastolic range from 60 to 90. Diastolic blood pressure represents the pressure in the arteries when the heart is at rest between beats. This range is considered normal and indicates a healthy blood pressure level. Values below 60 may indicate low blood pressure, while values above 90 may indicate high blood pressure.Rate this question:
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- 4.
The average adult pulse rate rages
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50-85
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65-95
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65-100
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80-110
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70-100
Correct Answer
A. 70-100Explanation
The correct answer is 70-100. This range represents the average adult pulse rate, which is the number of times the heart beats per minute. A pulse rate below 70 may indicate bradycardia, a condition where the heart beats too slowly, while a pulse rate above 100 may indicate tachycardia, a condition where the heart beats too fast. Therefore, a pulse rate between 70-100 is considered normal for an average adult.Rate this question:
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- 5.
The average pulse rate for an infant ranges
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90-100
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45-95
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100-180
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110-120
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120-200
Correct Answer
A. 100-180Explanation
The correct answer is 100-180. This range is considered the average pulse rate for an infant. It is normal for an infant's pulse rate to fall within this range. A pulse rate below 100 or above 180 may indicate a potential health issue and should be monitored or evaluated by a healthcare professional.Rate this question:
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- 6.
On a single -row detector scanner, which of the following does not decrease the pt dose
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Decreasing the scan time while leaving the mA constant
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Decreasing the slice thickness while covering the same anatomical region
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Reformat the data instead of rescanning
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Increasing the pitch
Correct Answer
A. Decreasing the slice thickness while covering the same anatomical regionExplanation
Decreasing the slice thickness while covering the same anatomical region does not decrease the patient dose. This is because decreasing the slice thickness allows for more detailed imaging of the anatomical region, but it does not affect the amount of radiation exposure the patient receives. The dose of radiation is determined by factors such as the mA setting and the scan time, which are not changed in this scenario. Therefore, decreasing the slice thickness does not decrease the patient dose.Rate this question:
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- 7.
Blood urea nitrogen level of ---mg/dl is considered outside the normal range
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10
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18
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32
Correct Answer
A. 32Explanation
A blood urea nitrogen (BUN) level of 32 mg/dl is considered outside the normal range. BUN is a measure of the amount of nitrogen in the blood that comes from the waste product urea. Higher BUN levels can indicate kidney dysfunction or dehydration, while lower levels can be a sign of liver disease or malnutrition. The normal range for BUN levels is typically between 7 and 20 mg/dl, so a level of 32 mg/dl would be considered elevated and may require further investigation or medical attention.Rate this question:
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- 8.
If there is no overlap or gabetween adjacent slices of a ct scan, CTDI-----MSAD
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IS LESS THAN
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EQUALS
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IS MUCH GREATER THAN
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IS SLIGHTLY GREATER THAN
Correct Answer
A. EQUALSExplanation
If there is no overlap or gap between adjacent slices of a CT scan, the CTDI (Computed Tomography Dose Index) value will be equal to the MSAD (Mean Slice Aggregated Dose). This means that the average radiation dose delivered to each slice will be the same as the overall dose delivered to the patient.Rate this question:
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- 9.
WHICH OF THE FOLLOWING REDUCES PATIENT DOSE AT THE EXPENSE OF INCREASING TTHE APPARENT NOISE IN THE IMAGE
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KVP
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PITCH
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TABLE INCREMENT
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MAS
Correct Answer
A. MASExplanation
MAS stands for milliampere-seconds, which refers to the product of the tube current (measured in milliamperes) and the exposure time (measured in seconds). Increasing the MAS will increase the radiation dose delivered to the patient, but it will also increase the number of X-ray photons reaching the image receptor, resulting in a higher signal-to-noise ratio. Therefore, increasing the MAS will reduce patient dose at the expense of increasing the apparent noise in the image.Rate this question:
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- 10.
------------------scanner design was the first to acquire four slices in a single rotation
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Second-generation
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Third generation
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Multi-row detector
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Continuous rotation
Correct Answer
A. Multi-row detectorExplanation
The correct answer is "multi-row detector" because this type of scanner design was the first to acquire four slices in a single rotation. This means that the multi-row detector technology allowed for faster and more efficient scanning of the body, as it could capture multiple slices of images simultaneously. This advancement in scanner design greatly improved the speed and accuracy of medical imaging, making it a significant development in the field.Rate this question:
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- 11.
Which of the following is a component not normally located in the gantry of a modern ct system
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Pre-patient collimator
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Solid-state detectors
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Array processor
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X-ray tube
Correct Answer
A. Array processorExplanation
An array processor is not normally located in the gantry of a modern CT system. The gantry of a CT system typically houses components such as the x-ray tube, detectors, and collimators. The array processor, on the other hand, is a separate component that processes the data collected by the detectors to generate the final CT images. It is usually located outside of the gantry, in the main computer system of the CT scanner.Rate this question:
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- 12.
Bremsstrahlung radiation does not include which type of electron activity
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Collision btw an incoming electron and the nucleus of the target atom
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Collision btw an incoming electron and an electron in an inner shell of the target atom
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Slowing down of an incoming electron due to the effect of passing close to the positive charge of the nucleus of the target atom
Correct Answer
A. Collision btw an incoming electron and an electron in an inner shell of the target atomExplanation
Bremsstrahlung radiation refers to the electromagnetic radiation emitted when an incoming electron is deflected or slowed down by the electric field of a nucleus. This deflection or slowing down can occur due to the electron colliding with the nucleus of the target atom or due to the electron passing close to the positive charge of the nucleus. However, it does not involve a collision between the incoming electron and an electron in an inner shell of the target atom.Rate this question:
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- 13.
Which of the following statement is FALSE regarding occurrences after an x-ray photon penetrates the detector aperture
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The photon can pass through the detector unmeasured
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The photon is conveted completely into an electron
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The measured signal is enhanced by an emplifier
Correct Answer
A. The photon is conveted completely into an electronExplanation
The statement that the photon is converted completely into an electron is false. When an x-ray photon penetrates the detector aperture, it may pass through the detector unmeasured or interact with the detector material. In the case of interaction, the photon transfers only a portion of its energy to an electron in the detector material through a process called photoelectric effect or Compton scattering. The electron is then detected and contributes to the measured signal. However, the photon itself is not converted completely into an electron.Rate this question:
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- 14.
Ct images can be directly scanned in planes other than transverse by
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Orienting the pt body part so that it is not perpendicular to the xpray beam
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Tilting the gantry
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Changing the angle that the x-ray beam leaves the tube
Correct Answer(s)
A. Orienting the pt body part so that it is not perpendicular to the xpray beam
A. Tilting the gantryExplanation
CT images can be directly scanned in planes other than transverse by orienting the patient's body part so that it is not perpendicular to the x-ray beam. This means positioning the body part at an angle to the beam, allowing for imaging in different planes. Tilting the gantry is another method that can be used to achieve imaging in planes other than transverse. By changing the angle that the x-ray beam leaves the tube, the gantry can be adjusted to capture images in different orientations.Rate this question:
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- 15.
Which of the following is false about the spatial resoultion of an image?
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Resolution is dependent on matrix size
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Resolution is dependent on reconstruction FOV
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Resolution is dependent on scanned FOV
Correct Answer
A. Resolution is dependent on scanned FOVExplanation
The spatial resolution of an image is not dependent on the scanned FOV. Spatial resolution refers to the level of detail that can be seen in an image, and it is determined by factors such as the matrix size and the reconstruction FOV. The scanned FOV, on the other hand, refers to the area that is actually captured during the scanning process. While the scanned FOV can affect the overall size of the image, it does not directly impact the spatial resolution.Rate this question:
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- 16.
If the slice thickness is changed from 5mm to 7mm and all other parameters are held constant,-----% more photons will be used inmaking the slice
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30
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40
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60
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60
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80
Correct Answer
A. 40Explanation
If the slice thickness is changed from 5mm to 7mm, the volume of the slice will increase. Since all other parameters are held constant, the number of photons used to make the slice needs to increase in order to maintain the same level of image quality. The increase in slice thickness requires more photons to penetrate through the thicker slice, resulting in a 40% increase in the number of photons used.Rate this question:
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- 17.
If a reconstruction FOV of 32 cm and a 512 x 512 matrix are used, the pixel size is ----mm
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0.35
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0.625
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1.6
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3.25
Correct Answer
A. 0.625Explanation
pixel size is equal to reconstruction FOV divided by matrix 320mm divide by 512Rate this question:
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- 18.
Which of the following does not occure when reconstruction FOV is decreased
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Spatial resolution is increased
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Pixel size is increased
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Noise in the image increases
Correct Answer
A. Pixel size is increasedExplanation
When the reconstruction FOV (Field of View) is decreased, it means that a smaller area of the image is being reconstructed. This has an impact on the size of the pixels in the image. When the FOV is decreased, the pixel size is reduced, resulting in smaller pixels. Therefore, the correct answer is that the pixel size is increased when the reconstruction FOV is decreased.Rate this question:
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- 19.
The smalles object that can be resolved if a reconstruction FOV of 24 cm and a 512 x 512 matrix are used is ------mm
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0.47
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1.00
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2.13
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3.57
Correct Answer
A. 0.47Explanation
The smallest object that can be resolved in this scenario can be calculated using the formula: resolution = FOV / matrix size. In this case, the resolution would be 24 cm / 512 = 0.047 cm. Since the answer choices are in millimeters, we need to convert 0.047 cm to mm, which gives us 0.47 mm. Therefore, the correct answer is 0.47.Rate this question:
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- 20.
If the radiologist requires 2mm thick contiguous slices through the pituitary, and 2.4 cm of coverage,----slices are necessary?
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8
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10
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12
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13
Correct Answer
A. 12Explanation
To calculate the number of slices necessary, we need to convert the coverage of 2.4 cm to millimeters, which equals 24 mm. Then, we divide the coverage by the thickness of each slice (2 mm) to get the number of slices needed. In this case, 24 mm divided by 2 mm equals 12 slices. Therefore, 12 slices are necessary to meet the radiologist's requirements.Rate this question:
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- 21.
Which of the following is not a result of reducing the reconstruction FOV?
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Improved spatial resolution
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Increased appearance of image noise
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Anatomical structures appear smaller
Correct Answer
A. Anatomical structures appear smallerExplanation
Reducing the reconstruction FOV refers to decreasing the area of the image that is reconstructed. This means that less anatomical structures will be included in the final image, resulting in them appearing smaller. Therefore, the correct answer is that anatomical structures appear smaller.Rate this question:
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- 22.
150mm FOV a wecond 300mm FOV which of the following statements is false
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The second set resoulution is better than the first set
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Noise in the second set more pronounced than first set
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Pt dose of the first set higher than the second set
Correct Answer(s)
A. The second set resoulution is better than the first set
A. Noise in the second set more pronounced than first set
A. Pt dose of the first set higher than the second setExplanation
The correct answer is "the second set resolution is better than the first set, noise in the second set more pronounced than first set, pt dose of the first set higher than the second set". This means that all of these statements are false. The first set has a higher resolution than the second set, the noise in the first set is more pronounced than the second set, and the patient dose in the first set is higher than the second set.Rate this question:
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- 23.
Which of the following parameters causes helical slices to be reconstructed so they overlap
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Table increment
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Reconstruction interval
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Pitch
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Collimation
Correct Answer
A. Reconstruction intervalExplanation
The reconstruction interval parameter determines the spacing between consecutive slices during the reconstruction process. If the reconstruction interval is smaller than the collimation (width of the X-ray beam), it causes helical slices to be reconstructed so they overlap. This means that there will be some overlap between adjacent slices, resulting in a smoother and more continuous representation of the scanned object.Rate this question:
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- 24.
Which of the following can be changed retrospectively?
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Slice thickness from an MDCT helical scan
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The slice overlap from a single row detector scanner helical scan
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The slice thickness from a single-row detector scanner helical scan
Correct Answer(s)
A. Slice thickness from an MDCT helical scan
A. The slice overlap from a single row detector scanner helical scanExplanation
The slice thickness from an MDCT helical scan can be changed retrospectively. This means that after the scan has been performed, the thickness of the slices can be adjusted or modified. Similarly, the slice overlap from a single row detector scanner helical scan can also be changed retrospectively. However, the slice thickness from a single-row detector scanner helical scan cannot be changed retrospectively, meaning that once the scan is done, the thickness of the slices cannot be altered.Rate this question:
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- 25.
Which of the following values for pitch would stretch the x-ray helix the most?
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1.0
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1.5
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0.5
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0.8
Correct Answer
A. 1.5Explanation
A larger value for pitch would stretch the x-ray helix more. In this case, the value of 1.5 is the largest among the given options, so it would stretch the x-ray helix the most.Rate this question:
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- 26.
For a given distance of coverage, which of the following is true?
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Reconstruction FOV increases, pt. dose increases
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As pitch increases, pt. dose decreases
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As slice thickness increases, pt. dose decreases
Correct Answer(s)
A. As pitch increases, pt. dose decreases
A. As slice thickness increases, pt. dose decreasesExplanation
As the pitch increases, the table moves faster during scanning, resulting in less overlap between adjacent slices. This reduces the amount of radiation exposure to the patient, hence decreasing the patient dose. Similarly, as the slice thickness increases, there is less radiation exposure to the patient as the X-ray beam covers a larger area. Therefore, the patient dose decreases with an increase in pitch and slice thickness.Rate this question:
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- 27.
Which of the following is true regarding barium sulfate solutions used in ct
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They are less concentrated than those used in conventional radiography
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They are the same as those used in x-ray
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They are in no way related to those used in x-ray
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They are more concentrated than those used in x-ray
Correct Answer
A. They are less concentrated than those used in conventional radiographyExplanation
Barium sulfate solutions used in CT scans are less concentrated than those used in conventional radiography. This is because CT scans require a lower concentration of barium sulfate to achieve the desired contrast in the images. CT scans use a combination of X-rays and computer technology to create detailed cross-sectional images of the body, whereas conventional radiography uses X-rays alone. Therefore, the concentration of barium sulfate needed for CT scans is lower compared to conventional radiography.Rate this question:
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- 28.
Which of the following oral contrast agents is better for opacifying the distal small intestine
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An ionic iodinated contrast agent
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A non-ioni iodinated contrast agent
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Barium sufate
Correct Answer
A. Barium sufateExplanation
Barium sulfate is a better oral contrast agent for opacifying the distal small intestine because it is not absorbed by the body and provides excellent visualization of the gastrointestinal tract. Ionic iodinated contrast agents and non-ionic iodinated contrast agents are primarily used for imaging blood vessels and organs, and they are not as effective in opacifying the small intestine.Rate this question:
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- 29.
A delay of about ----seconds after the start of the IV contrast injection should be used for helical scan of the neck
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20
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50
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35
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75
Correct Answer
A. 35Explanation
A delay of about 35 seconds after the start of the IV contrast injection should be used for helical scan of the neck. This delay allows for optimal distribution of the contrast agent throughout the blood vessels in the neck, ensuring clear and accurate imaging of the area. A shorter delay may result in inadequate contrast enhancement, while a longer delay may lead to excessive contrast dispersion and reduced image quality. Therefore, a delay of 35 seconds strikes a balance between these factors and is considered optimal for this procedure.Rate this question:
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- 30.
A difference in density of -------HU between the aorta and the inferior vena cava would indicate the non-equilibrium phase of enhancement
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43
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35
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25
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8
Correct Answer
A. 25Explanation
A difference in density of 25 HU between the aorta and the inferior vena cava would indicate the non-equilibrium phase of enhancement. This means that there is a difference in the amount of contrast agent present in these two blood vessels, suggesting that the contrast agent is still being distributed and not yet fully equilibrated.Rate this question:
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- 31.
There is substantial enhancement of the liver compared to tumors during the ------phase, but during the --------phase, there is the possibility of tumor enhancement, whichmay make hepatic tumors isodense with liver tissue
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Bolus, equilibrium
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Non-equilibrium equilibrium
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Non-equilibrium, bolus
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Equilibrium, non-equilibrum
Correct Answer
A. Non-equilibrium equilibriumExplanation
During the non-equilibrium phase, there is substantial enhancement of the liver compared to tumors. This means that the liver tissue will appear brighter or more enhanced compared to the tumors. However, during the equilibrium phase, there is a possibility of tumor enhancement, which may make the hepatic tumors isodense with liver tissue. This means that the tumors and the liver tissue may have similar levels of enhancement, making it difficult to distinguish between them.Rate this question:
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- 32.
The portal venous phase occurs about-----seconds after the start of the IV contrast injection
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20 to 30
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40 to 60
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60 to 90
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90 to120
Correct Answer
A. 60 to 90Explanation
The portal venous phase occurs approximately 60 to 90 seconds after the start of the IV contrast injection. During this phase, the contrast material has reached the portal vein and is circulating through the liver, allowing for optimal visualization of the liver and its vasculature. This phase is important for detecting abnormalities in the liver, such as tumors or vascular lesions.Rate this question:
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- 33.
The hepatic arterial phase occurs about-------seconds after the start of the Iv contrast injection
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60 to 80
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40 to 60
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20 to 40
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0 to 20
Correct Answer
A. 20 to 40Explanation
The hepatic arterial phase occurs approximately 20 to 40 seconds after the start of the IV contrast injection. During this phase, the contrast agent reaches the liver through the hepatic artery, allowing for visualization of the arterial blood supply to the liver. This phase is important in detecting and evaluating liver tumors, as they typically receive their blood supply from the hepatic artery. Timing the scan appropriately ensures optimal visualization of the arterial phase and accurate assessment of liver pathology.Rate this question:
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- 34.
Delay of about-----seconds afte the start of the IV contrast injection should be used for a helical scan of the chest
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45
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35
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25
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15
Correct Answer
A. 25Explanation
A delay of about 25 seconds after the start of the IV contrast injection should be used for a helical scan of the chest. This delay allows the contrast to circulate through the blood vessels and enhance the visualization of the chest structures. A shorter delay may result in inadequate contrast enhancement, while a longer delay may lead to excessive contrast dispersion and potential loss of image quality. Therefore, a delay of 25 seconds strikes a balance between optimal contrast enhancement and image quality.Rate this question:
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- 35.
Which of the following is a typical scan delay following the start of the injection for helical ct examinations of the pancreas?
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50 to 60
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70 to 80
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80 to 90
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2 to 3 min
Correct Answer
A. 50 to 60Explanation
A typical scan delay following the start of the injection for helical CT examinations of the pancreas is 50 to 60 seconds. This delay allows for the contrast material to reach the pancreas and enhance the visualization of the organ during the scan.Rate this question:
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- 36.
Barium sulfate oral contrast media would be selected instead of iodinated oral contrast media because:
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It passes through the GI tract more quickly
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The trauma patient may have a perforated bowel
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The contrast media stays more dense in the distal GI track
Correct Answer
A. The contrast media stays more dense in the distal GI trackExplanation
Barium sulfate oral contrast media is selected instead of iodinated oral contrast media because it stays more dense in the distal GI tract. This is important for imaging purposes as it allows for better visualization and assessment of the lower gastrointestinal structures. Additionally, barium sulfate passes through the GI tract more quickly, which can be advantageous in certain situations. However, the fact that the trauma patient may have a perforated bowel is not a determining factor in the selection of the contrast media.Rate this question:
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- 37.
Crania nerves VII what kind of nerve and may be visualized during a study of ?
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Vestibulocochlear/soft tissue
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Facial nerve/soft tisue
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Glossopharyngeal nerve/IAC
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Vagus nerve/IAC
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Facial nerve/IAC
Correct Answer
A. Facial nerve/IACExplanation
The correct answer is facial nerve/IAC. The question is asking about the type of nerve that may be visualized during a study of the internal auditory canal (IAC). The facial nerve is one of the cranial nerves (cranial nerve VII) and it passes through the IAC. Therefore, during a study of the IAC, the facial nerve can be visualized.Rate this question:
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- 38.
VIII what kind of nerve where is visualized
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Facial nerve/IAC
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Vestibulocochlear/softtissu
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Vagus nerve/IAC
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Vestibulocochlear/IAC
Correct Answer
A. Vestibulocochlear/IACExplanation
The correct answer is vestibulocochlear/IAC. The question is asking about the kind of nerve that is visualized in a specific location. The abbreviation "IAC" likely refers to the internal auditory canal. The vestibulocochlear nerve, also known as the eighth cranial nerve, is responsible for transmitting auditory and balance information from the ear to the brain. Therefore, it makes sense that this nerve would be visualized in the internal auditory canal.Rate this question:
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- 39.
IX what kind of nerve and where is visualized
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Glossopharyngeal nerve/IAC
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Vagus nerve/softtissue
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Facialnerve/IAC
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Glossopharyngeal /softtissue
Correct Answer
A. Glossopharyngeal /softtissueExplanation
The glossopharyngeal nerve is visualized in soft tissue.Rate this question:
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- 40.
X what kind of nerve and where is showes
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Vagus nerve/softtissue
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Facial nerve/IAC
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Accessory nerve/softtissue
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Vestivulocochlear/ IAC
Correct Answer
A. Vagus nerve/softtissueExplanation
The correct answer is the vagus nerve/soft tissue. The vagus nerve is a cranial nerve that extends from the brainstem to various organs in the body. It is responsible for controlling various bodily functions such as heart rate, digestion, and breathing. The term "soft tissue" refers to the non-bony structures in the body, including muscles, tendons, and connective tissues. Therefore, the vagus nerve is located within the soft tissues of the body.Rate this question:
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- 41.
XI what kind of nerve and where is visualized
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Glossopharyngeal/IAC
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Vagus nerve/softtissue
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Accessory nerve/softtissue
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Hypoglossal nerve/softtissue
Correct Answer
A. Accessory nerve/softtissueExplanation
The correct answer is the accessory nerve/soft tissue. The question is asking about the kind of nerve and where it is visualized. The accessory nerve is a cranial nerve that controls the muscles of the neck and shoulder. It is typically visualized in soft tissue imaging, such as an MRI or CT scan.Rate this question:
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- 42.
XII what kind of nerve/where it may showes
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Vestibulocochlear/IAC
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Glossopharyngeal nerve/softtissue
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Hypoglossal nerve/soft tissues
Correct Answer
A. Hypoglossal nerve/soft tissuesExplanation
The hypoglossal nerve is responsible for controlling the movement of the tongue. It innervates the muscles of the tongue, allowing it to move and function properly. Soft tissues refer to the muscles, connective tissues, and other structures in the body that are not bone or cartilage. Therefore, the hypoglossal nerve is most likely to be found in soft tissues.Rate this question:
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- 43.
Cranial nerves are not seen in the region of the
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Cervical spine
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Internal auditory canal
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Supratentorium
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Soft tissue neck
Correct Answer
A. SupratentoriumExplanation
The cranial nerves are a set of 12 pairs of nerves that emerge directly from the brain and are responsible for various functions related to sensory and motor control of the head and neck. They are not seen in the region of the supratentorium, which refers to the area of the brain located above the tentorium cerebelli. The cranial nerves are primarily located within the cranial cavity and do not extend into the supratentorial region. Therefore, the supratentorium is the correct answer as it is not a location where cranial nerves are found.Rate this question:
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- 44.
Contrast should not be administred for
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Atrophy
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Cerebral trauma
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Hydorcephalus
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Dementia
Correct Answer(s)
A. Atrophy
A. Cerebral trauma
A. Hydorcephalus
A. Dementia -
- 45.
In which the patient blows the cheeks out in order to distend th epyriform sinuse
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Letter e
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Valsalva maneuver
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Epiglottis
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Demonstrates vocal cord
Correct Answer
A. Valsalva maneuverExplanation
The Valsalva maneuver is a technique where the patient blows air out forcefully while keeping their mouth and nose closed. This increases the pressure in the chest and abdomen, causing the pyriform sinuses to distend. The pyriform sinuses are located in the throat and are important for swallowing. The other options, such as epiglottis and vocal cords, are not directly related to the action of blowing the cheeks out to distend the pyriform sinuses.Rate this question:
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- 46.
Which of the following may reduce the out -of -fild artifact
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Increasing the scan fild-of-view
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Reducing the reconstruction field of view
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Reducing the slice thickness
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Increasing the martrix
Correct Answer
A. Increasing the scan fild-of-viewExplanation
Increasing the scan field-of-view may reduce the out-of-field artifact. Out-of-field artifacts occur when the imaged object extends beyond the field-of-view of the scanner. By increasing the scan field-of-view, a larger area of the object can be captured, reducing the likelihood of artifacts occurring outside the field-of-view. This allows for a more comprehensive and accurate representation of the imaged object.Rate this question:
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- 47.
A cone beam artifact may look like stars:
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At the center of the image
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Coming from structures around the edge of the image
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Coming from cone-shaped structures
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From all structures with hight ct numbers
Correct Answer
A. Coming from structures around the edge of the imageExplanation
Cone beam artifacts can appear as stars coming from structures around the edge of the image. This is because cone beam artifacts occur when the X-ray beam is not aligned with the center of rotation, causing distortion in the image. As a result, structures located near the edge of the image may appear as star-like shapes due to the cone-shaped nature of the beam.Rate this question:
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- 48.
Which of the following affects beam hardening
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the types of tissues the beam passes through
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The thickness of the tissues traversed by the beam
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The energies of the photons in the beam
Correct Answer(s)
A. the types of tissues the beam passes through
A. The thickness of the tissues traversed by the beam
A. The energies of the photons in the beamExplanation
Beam hardening is a phenomenon that occurs in computed tomography (CT) imaging when the X-ray beam passes through different types and thicknesses of tissues. As the X-ray beam passes through different tissues, it gets attenuated differently, causing a change in the energy spectrum of the photons in the beam. This change in energy spectrum leads to beam hardening artifacts in the resulting CT image. Therefore, both the types of tissues and the thickness of the tissues traversed by the beam, as well as the energies of the photons in the beam, can affect beam hardening.Rate this question:
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- 49.
Which of the following would display the greates amount of partial volume artifact
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10mm slice from a 20 slice study
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A 5 mm slice from a 40 slice study
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5 mm slice from 20 slice study
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A, b and c would exprince the same amount of partial volume artifact
Correct Answer
A. 10mm slice from a 20 slice studyExplanation
The 10mm slice from a 20 slice study would display the greatest amount of partial volume artifact. This is because a thicker slice (10mm) is more likely to contain multiple tissue types within its volume, leading to partial volume averaging and blurring of the boundaries between these tissues. In contrast, a thinner slice (5mm) would have less partial volume artifact as it would capture a more precise representation of the individual tissues. The number of slices in the study (20 or 40) does not directly affect the amount of partial volume artifact.Rate this question:
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Mar 21, 2023Quiz Edited by
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Apr 08, 2010Quiz Created by
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