Medical CT Registry Exam Review MCQ Test!
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Try this Medical CT registry exam review MCQ test that we've prepared below for you. This CT registry review test is designed for technologists who need to prepare and pass the CT certification exam. You must already know that computed tomography (CT) is an imaging procedure that uses special x-ray equipment to create detailed scans of areas inside the body. Test your understanding of this concept by taking the quiz below and acing that upcoming final exam!
Questions and Answers
- 1.
What is an advantage of scans of the pituitary taken in the coronal plane?
- A.
IV contrast material is better visualized.
- B.
Streak artifacts are reduced or eliminated.
- C.
The patient is more comfortable during scanning.
- D.
The patient receives a lower radiation dose.
Correct Answer
B. Streak artifacts are reduced or eliminated.Explanation
Scans of the pituitary taken in the coronal plane have the advantage of reducing or eliminating streak artifacts. Streak artifacts are unwanted streaks or lines that can appear on an image due to various factors such as metal objects, dense tissues, or motion. By taking scans in the coronal plane, which is a vertical plane that divides the body into front and back halves, the likelihood of streak artifacts is minimized. This allows for clearer and more accurate visualization of the pituitary gland, leading to better diagnostic outcomes.Rate this question:
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- 2.
Which two strategies can reduce the effect of dental fillings in a sinus study?
- A.
High mA and short scan time.
- B.
Low kVp and high contrast, or bone algorithm.
- C.
Adjust the angle of the gantry and widen the window width.
- D.
Small focal spot and small display field.
Correct Answer
C. Adjust the angle of the gantry and widen the window width. -
- 3.
Which of the following is affected by the slice spacing in a CT study?
- A.
Spatial Resolution
- B.
Quantum Mottle
- C.
Radiation Dose to the Patient
- D.
Signal-to-Noise Ration
Correct Answer
C. Radiation Dose to the PatientExplanation
The slice spacing in a CT study refers to the distance between two consecutive slices. This spacing affects the radiation dose to the patient. A smaller slice spacing means that more slices are taken, resulting in a higher radiation dose to the patient. Conversely, a larger slice spacing means that fewer slices are taken, resulting in a lower radiation dose to the patient. Therefore, the radiation dose to the patient is directly affected by the slice spacing in a CT study.Rate this question:
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- 4.
What is the name of the pinecone-shaped structure of the brain the can often be seen as calcified in CT images?
- A.
Choroid Plexus
- B.
Pineal Gland
- C.
Caudate Nucleus
- D.
Middle cerebral Artery
Correct Answer
B. Pineal GlandExplanation
The pineal gland is a small pinecone-shaped structure located in the brain. It is often seen as calcified in CT images, which means that it can appear as a white, dense area on the scan. The pineal gland plays a role in regulating sleep patterns and producing melatonin, a hormone that helps control the sleep-wake cycle. Its calcification can sometimes be associated with certain disorders or conditions, such as pineal gland tumors or calcium deposits.Rate this question:
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- 5.
Third generation (rotate/rotate) scanners overcame which of the following limitations?
- A.
Detector singal drift sensitivity
- B.
Translation motion
- C.
Spurious signals from moving signal wires
- D.
Cost
Correct Answer
B. Translation motionExplanation
Third generation (rotate/rotate) scanners overcame the limitation of translation motion. Translation motion refers to the linear movement of the scanner, which can cause blurring and distortions in the scanned image. Third generation scanners, with their rotating mechanism, eliminated the need for translation motion, resulting in more accurate and high-quality scans.Rate this question:
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- 6.
What helical or spiral computed tomography term is defined as the table increment in distance per mm per 360 degrees gantry rotation divided by the section thickness in mm?
- A.
Rotation
- B.
Spiral
- C.
Helix
- D.
Pitch
Correct Answer
D. PitchExplanation
Pitch is the term that is defined as the table increment in distance per mm per 360 degrees gantry rotation divided by the section thickness in mm. In helical or spiral computed tomography, pitch refers to the distance the table moves per one complete rotation of the gantry. It is an important parameter that determines the speed at which the scanner acquires images and affects the image quality and radiation dose. A higher pitch value indicates a faster scan but lower image quality, while a lower pitch value provides better image quality but slower scan speed.Rate this question:
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- 7.
What determines the section thickness?
- A.
Scan arc
- B.
Filtration algorithm
- C.
Incident beam collimation
- D.
Detector alignment
Correct Answer
C. Incident beam collimationExplanation
The section thickness is determined by the incident beam collimation. Incident beam collimation refers to the process of narrowing down the size of the beam before it interacts with the sample. By controlling the collimation, the size of the beam can be adjusted, which in turn affects the section thickness. A narrower beam will result in a thinner section, while a wider beam will result in a thicker section. Therefore, incident beam collimation plays a crucial role in determining the section thickness.Rate this question:
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- 8.
What change will occur in the number of detected photons if a section thickness is changed from 5 mm to 10mm?
- A.
Decrease 50%
- B.
Decrease 25%
- C.
Increase 50%
- D.
Increase 100%
Correct Answer
D. Increase 100%Explanation
If the section thickness is changed from 5 mm to 10 mm, the number of detected photons will increase by 100%. This is because the thicker section allows for more photons to interact with the detector, resulting in a higher number of photons being detected.Rate this question:
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- 9.
Which of the following will magnify the image?
- A.
Increase the field of view.
- B.
Decreasing field of view.
- C.
Increasing section thickness.
- D.
Decreasing section thickness.
Correct Answer
B. Decreasing field of view.Explanation
Decreasing the field of view will magnify the image because a smaller field of view allows for a closer and more detailed view of the object. When the field of view is decreased, the same amount of information is concentrated into a smaller area, resulting in a magnified image.Rate this question:
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- 10.
Which of the following is convolution?
- A.
Filtered back projection
- B.
Fourier transform
- C.
Iterative filtration
- D.
3-d rendering
Correct Answer
A. Filtered back projectionExplanation
Filtered back projection is a mathematical technique used in computed tomography (CT) imaging to reconstruct an image from a series of x-ray projections. It involves convolving the projections with a filter function before back projecting them to form the final image. Convolution is a mathematical operation that combines two functions to produce a third function that represents how one function affects the other. In the case of filtered back projection, the convolution is performed between the projections and the filter function, making it the correct answer.Rate this question:
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- 11.
Which of the following determines the maximum number of shades of gray that can be displayed on the CT monitors?
- A.
Window level
- B.
Window width
- C.
Pixel size
- D.
Matrix size
Correct Answer
B. Window widthExplanation
The maximum number of shades of gray that can be displayed on CT monitors is determined by the window width. Window width refers to the range of Hounsfield units that are displayed on the monitor. A wider window width allows for a larger range of shades of gray to be displayed, resulting in more detailed and nuanced images. On the other hand, a narrower window width will limit the number of shades of gray that can be displayed, resulting in a less detailed image.Rate this question:
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- 12.
Which of the following are benefits of narrower section thicknesses?
- A.
Reduced partial volume averaging and improved spatial resolution
- B.
Decreased scan time, and more anatomy covered
Correct Answer
A. Reduced partial volume averaging and improved spatial resolutionExplanation
Narrower section thicknesses in medical imaging can lead to reduced partial volume averaging, which occurs when multiple tissues are averaged together in one voxel, resulting in loss of detail. This reduction in partial volume averaging improves the spatial resolution of the image, allowing for better visualization and differentiation of structures.Rate this question:
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- 13.
Which of the following is the term used to describe a voxel value that is the average of multiple tissue types contained within the voxel?
- A.
Linear attenuation coefficient.
- B.
Partial volume averaging.
- C.
Low contrast resolution.
- D.
Edge gradient averaging.
Correct Answer
B. Partial volume averaging.Explanation
Partial volume averaging is the term used to describe a voxel value that is the average of multiple tissue types contained within the voxel. This occurs when a voxel contains a mixture of different tissues, and the resulting voxel value represents an average of the different tissue densities. This phenomenon can lead to a loss of spatial resolution and can affect the accuracy of measurements and diagnoses in medical imaging.Rate this question:
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- 14.
Which fo the following is the central value in a range of gray shades used to display the image?
- A.
Window width
- B.
Window level
- C.
Region of interest
- D.
Dose index
Correct Answer
B. Window levelExplanation
The central value in a range of gray shades used to display an image is referred to as the window level. This value determines the brightness or intensity of the image. By adjusting the window level, the user can control the overall brightness of the image, making it easier to visualize specific structures or abnormalities.Rate this question:
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- 15.
Which of the following increases the signal-to-noise ratio?
- A.
Increased mAs
- B.
Wider section thickness
- C.
Increased detection efficiency
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
Increasing mAs (milliamperes-seconds) in medical imaging increases the amount of X-ray photons produced, resulting in a stronger signal and improved signal-to-noise ratio. Wider section thickness refers to a larger slice of tissue being imaged, which can also increase the signal-to-noise ratio by capturing more information. Increased detection efficiency refers to using more sensitive detectors, such as a higher quantum efficiency detector, which can enhance the signal and reduce noise. Therefore, all three options listed - increased mAs, wider section thickness, and increased detection efficiency - can increase the signal-to-noise ratio in medical imaging.Rate this question:
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- 16.
What term is used to describe as the ability to display an image of a large object that is only slightly different in density from its surroundings?
- A.
Spatial resolution
- B.
Contrast resolution
- C.
Linearity
- D.
Clarity
Correct Answer
B. Contrast resolutionExplanation
Contrast resolution is the term used to describe the ability to display an image of a large object that is only slightly different in density from its surroundings. This means that the imaging technique has the capability to distinguish and visualize subtle differences in density or contrast between different tissues or structures in the body.Rate this question:
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- 17.
How often should an average CT number water calibration test be performed?
- A.
Daily
- B.
Monthly
- C.
Yearly
- D.
Weekly
Correct Answer
A. DailyExplanation
An average CT number water calibration test should be performed daily to ensure accurate and consistent results. This frequent testing helps to calibrate the CT scanner and maintain the accuracy of the CT number measurements. By performing the calibration test daily, any changes or drifts in the CT scanner's performance can be detected and corrected promptly, ensuring reliable and high-quality imaging.Rate this question:
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- 18.
What is the term that is used to describe contrast resolution?
- A.
High spatial detectibilty
- B.
Low spatial detectibilty
- C.
High contrast detectibilty
- D.
Low contrast detectibilty
Correct Answer
D. Low contrast detectibiltyExplanation
Low contrast detectability is the term used to describe the ability to distinguish subtle differences in contrast between objects or structures in an image. It refers to the ability of an imaging system to accurately detect and display small differences in contrast, which is important for identifying and diagnosing certain conditions or abnormalities. This term is often used in medical imaging, such as radiology, where the ability to detect low contrast details is crucial for accurate diagnosis.Rate this question:
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- 19.
What is the primary type of interaction that contributes to the subject contrast in CT images?
- A.
Pair production
- B.
Photoelectric effect
- C.
Compton scattering
- D.
Linear attenuation
Correct Answer
C. Compton scatteringExplanation
Compton scattering is the primary type of interaction that contributes to the subject contrast in CT images. Compton scattering occurs when an incoming X-ray photon interacts with an outer shell electron in the subject, causing the photon to change direction and lose some of its energy. This scattering process leads to variations in the intensity of X-rays detected by the CT scanner, which ultimately contributes to the contrast seen in the resulting images.Rate this question:
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- 20.
What type of scan geometry is responsible for producing ring artifacts?
- A.
Translate-rotate
- B.
Rotate-rotate
- C.
Rotate only
- D.
Helical / spiral
Correct Answer
B. Rotate-rotateExplanation
Rotate-rotate scan geometry is responsible for producing ring artifacts. In this type of scan geometry, the X-ray tube and detector rotate continuously around the patient in the same direction. This results in incomplete data acquisition and uneven sampling, leading to ring artifacts in the reconstructed images. These artifacts appear as concentric rings or circular patterns, causing image distortion and reducing image quality.Rate this question:
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- 21.
What is the cause for the "cupping" artifact?
- A.
The computer overcorrects for beam hardening
- B.
The beam encounters metal in the body
- C.
The body hardens the beam thus lowering the attenuation numbers in the center
- D.
The body hardens the beam thus increasing the attenuation numbers in the center
Correct Answer
C. The body hardens the beam thus lowering the attenuation numbers in the centerExplanation
The "cupping" artifact occurs because the body hardens the beam, which leads to lower attenuation numbers in the center. This means that the X-ray beam passing through the body is less attenuated in the central region compared to the surrounding areas. As a result, the central region appears brighter on the image, creating a cup-shaped appearance. This artifact can be caused by various factors such as variations in tissue density, composition, or thickness.Rate this question:
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- 22.
Which of the following can be described as bands and streaks that appear across an area due to bone and soft tissue attenuation values in the same pixel?
- A.
Tube arcing artifacts
- B.
Beam hardening artifacts
- C.
Partial volume artifacts
- D.
Full volume artifacts
Correct Answer
C. Partial volume artifactsExplanation
Partial volume artifacts can be described as bands and streaks that appear across an area due to bone and soft tissue attenuation values in the same pixel. These artifacts occur when a single pixel contains a mixture of different tissues, causing blurring and loss of detail in the image. This can happen when a voxel (a three-dimensional pixel) contains a combination of bone and soft tissue, resulting in a partial representation of each. This leads to the appearance of bands and streaks in the image.Rate this question:
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- 23.
Which of the following is a streak artifact oriented tangentially to a flat surface having a high spatial frequency?
- A.
Low contrast artifact
- B.
Edge gradient artifact
- C.
Equipment induced artifact
- D.
Signal artifact
Correct Answer
B. Edge gradient artifactExplanation
The correct answer is "edge gradient artifact." An edge gradient artifact is a streak artifact that occurs tangentially to a flat surface with a high spatial frequency. This artifact is caused by abrupt changes in pixel intensity along the edges of an object, resulting in streaks or lines appearing in the image. It is important to be aware of this artifact as it can affect the accuracy and interpretation of the image.Rate this question:
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- 24.
What filter selection would provide the best detail for imaging of the internal auditory canals?
- A.
Smooth
- B.
Sharp
- C.
Standard
- D.
Soft
Correct Answer
B. SharpExplanation
The filter selection that would provide the best detail for imaging of the internal auditory canals is "sharp." A sharp filter enhances the edges and fine details in an image, which is crucial for accurately visualizing the intricate structures of the internal auditory canals. Smooth, standard, and soft filters are not as effective in enhancing details and may result in a less clear and accurate image of the canals.Rate this question:
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- 25.
What anatomical structure forms a roof over the posterior cranial fossa and is shaped like a tent?
- A.
Tentorium cerebelli
- B.
Falx cerebri
- C.
Pontine cistern
- D.
Pia mater
Correct Answer
A. Tentorium cerebelliExplanation
The tentorium cerebelli is an anatomical structure that forms a roof over the posterior cranial fossa. It is shaped like a tent, with a horizontal portion separating the cerebellum from the occipital lobes of the brain. This structure provides support and protection to the brain, preventing downward displacement of the cerebellum. It also helps to compartmentalize the different regions of the brain, separating the cerebellum from the cerebral hemispheres.Rate this question:
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- 26.
Which of following results from a fracture in the temporal region of the skull with associated tearing of the middle meningeal artery?
- A.
Subdural hematoma
- B.
Epidural hematoma
- C.
Arteriovenous malformation
- D.
Subarchnoid hematoma
Correct Answer
B. Epidural hematomaExplanation
A fracture in the temporal region of the skull with associated tearing of the middle meningeal artery can result in an epidural hematoma. This occurs when blood accumulates between the skull and the dura mater, the outermost layer of the meninges. The middle meningeal artery is a branch of the maxillary artery, and if it is torn, it can lead to bleeding into the epidural space. This accumulation of blood can cause increased pressure within the skull, potentially leading to neurological symptoms and complications if not promptly treated.Rate this question:
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- 27.
Where is contrast media introduced for a myelography exam of the spinal canal?
- A.
Subdural space
- B.
Epidural space
- C.
Subarachnoid space
- D.
Spinal cord
Correct Answer
C. Subarachnoid spaceExplanation
Contrast media is introduced into the subarachnoid space for a myelography exam of the spinal canal. This space is located between the arachnoid mater and the pia mater, which surround the spinal cord. By injecting contrast media into the subarachnoid space, it can flow around the spinal cord and help visualize any abnormalities or blockages in the spinal canal. The subdural space is located between the dura mater and the arachnoid mater, the epidural space is located outside the dura mater, and the spinal cord is the structure within the spinal canal.Rate this question:
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- 28.
Which of the following anatomical structures would be visualized first when obtaining sagittal sections from right to left?
- A.
C-loop of the duodenum
- B.
Tail of the pancreas
- C.
Gallbladder
- D.
Right kidney
Correct Answer
C. GallbladderExplanation
When obtaining sagittal sections from right to left, the first anatomical structure that would be visualized is the gallbladder. Sagittal sections are taken in a vertical plane that divides the body into right and left halves. The gallbladder is located on the right side of the abdomen, close to the liver. Therefore, it would be the first structure encountered when moving from the right side to the left side of the body.Rate this question:
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- 29.
What type of drug is Demerol?
- A.
Analgesic
- B.
Antipyretic
- C.
Antianxiety agent
- D.
Local anesthetic
Correct Answer
A. AnalgesicExplanation
Demerol is classified as an analgesic drug. Analgesics are medications that are used to relieve pain. They work by blocking or reducing the sensation of pain in the body. Demerol, also known as meperidine, is a synthetic opioid analgesic that is commonly used to treat moderate to severe pain. It acts on the central nervous system to alleviate pain by binding to opioid receptors in the brain and spinal cord. As an analgesic, Demerol does not have antipyretic (fever-reducing), antianxiety, or local anesthetic properties.Rate this question:
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- 30.
Which of the following describes rapid, irregular, ineffective twitches of the ventricles?
- A.
Ventricular regurgitation
- B.
Ventricular palpitations
- C.
Ventricular arrythmia
- D.
Ventricular fibrillation
Correct Answer
D. Ventricular fibrillationExplanation
Ventricular fibrillation is a condition characterized by rapid, irregular, and ineffective twitches of the ventricles. During ventricular fibrillation, the heart's electrical signals become chaotic, causing the ventricles to quiver instead of contracting normally. This results in the heart being unable to pump blood effectively, leading to a lack of oxygen supply to the body. Ventricular fibrillation is a life-threatening condition that requires immediate medical intervention, such as defibrillation, to restore the heart's normal rhythm.Rate this question:
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- 31.
Which of the following is the more toxic cation that is incorporated into the organic ionic contrast media?
- A.
Sodium
- B.
Meglumine
- C.
Iodine
- D.
Calcium
Correct Answer
A. SodiumExplanation
Sodium is the correct answer because it is a cation that can be incorporated into organic ionic contrast media and is known to be more toxic compared to the other options listed (meglumine, iodine, and calcium). Sodium toxicity can cause various health issues, including electrolyte imbalances and cardiovascular problems.Rate this question:
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- 32.
What term is used to describe the computed tomography appearance of an intracerebral hemorrhage as a result of a higher CT number of the hemorrhage as compared to normal brain tissue?
- A.
Hyperdense
- B.
Isodense
- C.
Hypodense
- D.
Mass effect
Correct Answer
A. HyperdenseExplanation
Hyperdense is the correct answer because it refers to the computed tomography appearance of an intracerebral hemorrhage where the hemorrhage appears brighter or denser on the CT scan compared to normal brain tissue. This is due to the higher CT number of the hemorrhage, indicating a higher density of blood in the area. Isodense refers to when the hemorrhage has a similar density to normal brain tissue, hypodense refers to when the hemorrhage appears darker or less dense than normal brain tissue, and mass effect refers to the displacement or compression of brain tissue by the hemorrhage.Rate this question:
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- 33.
Which of the following provides optimal liver lesion detection following the introduction of contras media?
- A.
Scanning prior to the equilibrium phase
- B.
Scanning during to the equilibrium phase
- C.
Scanning after to the equilibrium phase
Correct Answer
A. Scanning prior to the equilibrium phaseExplanation
Scanning prior to the equilibrium phase provides optimal liver lesion detection following the introduction of contrast media. During this phase, the contrast agent is still being distributed throughout the liver, allowing for better visualization of any lesions present. Scanning during or after the equilibrium phase may result in suboptimal detection as the contrast agent has already reached a steady state and may not highlight lesions as effectively.Rate this question:
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- 34.
Which of the following is the recommended percentage of barium in a barium sulfate suspension utilized in abdominal computed tomography?
- A.
1-3%
- B.
10-20%
- C.
30%
- D.
50%
Correct Answer
A. 1-3%Explanation
The recommended percentage of barium in a barium sulfate suspension utilized in abdominal computed tomography is 1-3%. This concentration range is commonly used because it provides sufficient contrast for imaging while minimizing the risk of adverse effects or complications. Higher concentrations may lead to a higher risk of side effects such as diarrhea or constipation, while lower concentrations may result in inadequate visualization of the gastrointestinal tract. Therefore, a concentration of 1-3% is considered optimal for abdominal CT scans.Rate this question:
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- 35.
Which of the following are used in scintillation CT detectors?
- A.
Gadolinium based ceramic
- B.
Bismuth germanate
- C.
Calcium fluoride
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
The scintillation CT detectors use gadolinium based ceramic, bismuth germanate, and calcium fluoride. These materials are commonly used in scintillation detectors due to their ability to convert incident radiation into visible light. Gadolinium based ceramic has high stopping power and good energy resolution, making it suitable for detecting high-energy photons. Bismuth germanate has high density and fast decay time, making it ideal for detecting gamma rays. Calcium fluoride has high light yield and good energy resolution, making it useful for detecting X-rays and gamma rays.Rate this question:
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- 36.
Which of the following will have an effect on image quality?
- A.
Spatial resolution
- B.
Contrast resolution
- C.
Noise
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
Spatial resolution, contrast resolution, and noise all have an effect on image quality. Spatial resolution refers to the ability to distinguish between two objects that are close together, and a higher spatial resolution results in a clearer and more detailed image. Contrast resolution relates to the ability to differentiate between different shades of gray, and a higher contrast resolution leads to better visualization of subtle differences in tissue density. Noise refers to random variations in image intensity, and high levels of noise can reduce image clarity and make it difficult to identify structures. Therefore, all three factors play a crucial role in determining the quality of an image.Rate this question:
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- 37.
What are the primary advantages of narrower section thicknesses?
- A.
Improved spatial resolution
- B.
Reduced partial volume averaging
- C.
Higher contrast
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
Narrower section thicknesses in imaging provide several advantages. Firstly, they lead to improved spatial resolution, allowing for better visualization and distinction of small structures. Additionally, narrower section thicknesses reduce partial volume averaging, which occurs when multiple tissues are present within a single voxel and can cause blurring or loss of detail. Lastly, narrower section thicknesses can also result in higher contrast, enhancing the visibility and differentiation of different tissues or structures in the image.Rate this question:
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- 38.
Which of the following geometric factors will have an effect on spatial resolution? (Select all that apply.)
- A.
Focal spot size
- B.
Detector aperture width
- C.
Noise
Correct Answer(s)
A. Focal spot size
B. Detector aperture widthExplanation
The focal spot size and detector aperture width are both geometric factors that can affect spatial resolution. The focal spot size refers to the size of the X-ray beam produced by the X-ray tube, and a smaller focal spot size can result in better spatial resolution. The detector aperture width refers to the size of the detector used to capture the X-ray image, and a wider aperture width can also improve spatial resolution. Noise, on the other hand, is not a geometric factor and does not directly affect spatial resolution.Rate this question:
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- 39.
What term describes an artifact that may appear on a low dynamic range detector system near the shoulders and hips because dense bone has too severely attenuated the xray beam?
- A.
Beam hardening
- B.
Photon starvation
- C.
Ring
- D.
Partial volume
Correct Answer
B. Photon starvationExplanation
Photon starvation is the correct answer because it refers to the artifact that may appear on a low dynamic range detector system near the shoulders and hips. This artifact occurs when dense bone severely attenuates the x-ray beam, resulting in a lack of photons reaching the detector. As a result, there is a "starvation" of photons in these areas, leading to a noticeable artifact on the image.Rate this question:
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- 40.
Which of the following will help to reduce partial volume artifacts?
- A.
Scanning thinner sections
- B.
Scanning thicker sections
- C.
Scanning using a higher technique
- D.
Scanning using a lower technique
Correct Answer
A. Scanning thinner sectionsExplanation
Scanning thinner sections can help to reduce partial volume artifacts because when the sections are thinner, there is less overlap of different tissues within each voxel. This reduces the mixing of signals from different tissues, resulting in a more accurate representation of each individual tissue type. Consequently, the image will have improved spatial resolution and less blurring, leading to a reduction in partial volume artifacts.Rate this question:
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- 41.
Which of the following terms defines the increase in the mean energy of a polychromatic beam as it passes through an object?
- A.
Partial volume effect
- B.
Beam hardening
- C.
Cross-field uniformity
- D.
Linearity
Correct Answer
B. Beam hardeningExplanation
Beam hardening refers to the increase in the mean energy of a polychromatic beam as it passes through an object. This occurs because the lower energy photons are preferentially absorbed, resulting in a higher proportion of higher energy photons in the beam. This phenomenon can cause artifacts in computed tomography (CT) images, where the attenuation values of the object may be inaccurately represented due to the beam hardening effect.Rate this question:
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- 42.
Which of the following is the correct order for the stages of infection?
- A.
Incubation, prodomal, active, convalescence
- B.
Convalescence, active, prodomal, incubation
- C.
Prodomal, incubation, convalescence, active
- D.
Incubation, convalescence, prodomal, active
Correct Answer
A. Incubation, prodomal, active, convalescenceExplanation
The correct order for the stages of infection is as follows: incubation, prodomal, active, convalescence. During the incubation stage, the pathogen enters the body and starts to multiply. The prodomal stage is characterized by the onset of non-specific symptoms such as fever and fatigue. The active stage is when the infection is at its peak, with specific symptoms and the highest level of pathogen replication. Finally, the convalescence stage is the recovery period, where the symptoms gradually subside and the body returns to its normal state.Rate this question:
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- 43.
The term used to descibe the ability of a fluid to flow is
- A.
Density
- B.
Viscosity
- C.
Osmolality
- D.
Specific gravity
Correct Answer
B. ViscosityExplanation
Viscosity is the correct answer as it is the term used to describe the ability of a fluid to flow. Viscosity refers to the internal friction or resistance to flow within a fluid. It is a measure of how thick or sticky a fluid is, and it determines how easily the fluid can be poured or moved. Different fluids have different viscosities, with some being more viscous (thicker) and others less viscous (thinner).Rate this question:
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- 44.
A patient has a severe vagal reaction to iodinated contrast material that includes bradycardia. Initial treatment may include
- A.
Atropine
- B.
Diazapam
- C.
Rantidine hyrochloride (Zantac)
- D.
Albuterol sulfate (Proventil)
Correct Answer
A. AtropineExplanation
A severe vagal reaction to iodinated contrast material can cause bradycardia, which is a slow heart rate. Atropine is a medication that can be used to increase heart rate by blocking the action of the vagus nerve, which slows down the heart. Therefore, atropine would be an appropriate initial treatment for this patient to counteract the bradycardia caused by the vagal reaction. Diazepam is a sedative and would not directly address the bradycardia. Ranitidine hydrochloride is an antacid and would also not be effective for treating bradycardia. Albuterol sulfate is a bronchodilator and would not have a direct effect on heart rate.Rate this question:
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- 45.
Which of the following interactions between xray and matter results in the largest amount of occupational exposure?
- A.
Characteristic effect
- B.
Compton effect
- C.
Bremsstrahlung effect
- D.
Photoelectric effect
Correct Answer
B. Compton effectExplanation
The Compton effect is the correct answer because it involves the scattering of X-ray photons by the electrons in matter. This scattering can cause the X-ray photons to lose energy and change direction, resulting in a larger amount of occupational exposure. The other options, such as the characteristic effect, Bremsstrahlung effect, and photoelectric effect, also involve interactions between X-rays and matter but do not result in as much occupational exposure as the Compton effect.Rate this question:
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- 46.
The abdominal aorta bifurcates at the level of
- A.
T10
- B.
T12
- C.
L2
- D.
L4
Correct Answer
D. L4Explanation
The correct answer is L4. The abdominal aorta bifurcates at the level of L4 into the right and left common iliac arteries. This is an important anatomical landmark as it marks the transition from the abdominal aorta to the pelvis and lower extremities.Rate this question:
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- 47.
After the injection of intravenous contrast material during a CT examination of the brain, which of the following anatomic areas does not enhance?
- A.
Anterior communicating artery
- B.
Choroid plexus
- C.
Posterior horn of the lateral ventricle
- D.
Dura mater
Correct Answer
C. Posterior horn of the lateral ventricleExplanation
After the injection of intravenous contrast material, the blood vessels and tissues that receive a good blood supply will enhance or appear brighter on the CT scan. The anterior communicating artery, choroid plexus, and dura mater are all areas that have a rich blood supply and will enhance. However, the posterior horn of the lateral ventricle does not have a significant blood supply and therefore will not enhance on the CT scan.Rate this question:
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- 48.
The mathematical technique that involves the estimation of an unknown value from values on either side of it its known as
- A.
Filtering
- B.
Interpolation
- C.
Convolution
- D.
Summation
Correct Answer
B. InterpolationExplanation
Interpolation is the correct answer because it refers to the mathematical technique of estimating an unknown value based on known values on either side of it. It involves creating a function or curve that passes through the given data points and using this function to find the value at the desired point. Interpolation is commonly used in various fields such as mathematics, statistics, computer science, and engineering.Rate this question:
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- 49.
When compared with conventional radiography, CT produces diagnostic images with improved
- A.
Low-contrast resolution
- B.
Spatial resolution
- C.
Minute detail
- D.
Patient dose reduction
Correct Answer
A. Low-contrast resolutionExplanation
CT produces diagnostic images with improved low-contrast resolution compared to conventional radiography. This means that CT scans are able to detect and distinguish subtle differences in contrast between tissues or structures that may not be easily visible on conventional radiographs. This enhanced ability to visualize low-contrast details allows for better detection and characterization of abnormalities, leading to more accurate diagnoses.Rate this question:
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- 50.
Which of the following is not commonly used as a CT scintillation detector material?
- A.
Ceramic rare earth
- B.
Silver halide
- C.
Bismuth germinate
- D.
Cadmium tungstate
Correct Answer
B. Silver halideExplanation
Silver halide is not commonly used as a CT scintillation detector material. CT scintillation detectors are typically made from materials that can efficiently convert X-ray photons into visible light, such as ceramic rare earth, bismuth germinate, and cadmium tungstate. Silver halide, on the other hand, is commonly used in photographic films but not as a scintillation detector material in CT scans.Rate this question:
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Oct 16, 2023Quiz Edited by
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Apr 21, 2009Quiz Created by
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