Q.1 What type of medical imaging device uses sound waves to create pictures of the inside of the body?
X‑ray
Ultrasound
MRI
CT scan
Explanation - Ultrasound imaging uses high‑frequency sound waves that bounce off tissues to create images.
Correct answer is: Ultrasound
Q.2 Which imaging modality is best for visualizing bone fractures?
MRI
X‑ray
Ultrasound
PET scan
Explanation - X‑ray imaging uses ionizing radiation to produce clear images of bone structures, making it ideal for detecting fractures.
Correct answer is: X‑ray
Q.3 Which of these is NOT a typical use of a CT scanner?
Brain imaging after a head injury
Detecting lung nodules
Studying bone fractures
Measuring heart rate
Explanation - CT (Computed Tomography) provides detailed cross‑sectional images but does not directly measure heart rate; other modalities like ECG are used for that.
Correct answer is: Measuring heart rate
Q.4 What does MRI stand for?
Magnetic Resonance Imaging
Medical Radiology Imaging
Magnet Resonance Investigation
Molecular Radiography Interface
Explanation - MRI uses strong magnetic fields and radio waves to generate detailed images of soft tissues.
Correct answer is: Magnetic Resonance Imaging
Q.5 Which imaging technique is known for producing images without any ionizing radiation?
X‑ray
CT
Ultrasound
PET
Explanation - Ultrasound uses sound waves, not ionizing radiation, making it safe for frequent use.
Correct answer is: Ultrasound
Q.6 In which imaging modality does a small radioactive tracer called a radiopharmaceutical get injected into the bloodstream?
CT
Ultrasound
PET
X‑ray
Explanation - PET (Positron Emission Tomography) uses radiotracers to measure metabolic activity in tissues.
Correct answer is: PET
Q.7 Which imaging device uses a magnet to detect tiny vibrations in atoms inside the body?
CT
PET
MRI
X‑ray
Explanation - MRI employs a powerful magnetic field to align hydrogen atoms, which then emit signals that are used to construct images.
Correct answer is: MRI
Q.8 What is the main purpose of a contrast agent in medical imaging?
To reduce the noise in the image
To make certain tissues appear brighter or darker
To speed up the scan time
To protect the patient from radiation
Explanation - Contrast agents enhance the visibility of specific structures by altering the imaging signal of those tissues.
Correct answer is: To make certain tissues appear brighter or darker
Q.9 Which imaging modality uses a rotating X‑ray tube and a detector to create a 3‑dimensional image?
MRI
CT
Ultrasound
PET
Explanation - CT scanners rotate around the patient, gathering multiple X‑ray projections to reconstruct 3‑D cross‑sectional images.
Correct answer is: CT
Q.10 Which of these is a type of non‑ionizing imaging that can be used during pregnancy?
CT
X‑ray
PET
Ultrasound
Explanation - Ultrasound employs sound waves and is considered safe for use during pregnancy.
Correct answer is: Ultrasound
Q.11 What does the acronym DICOM stand for in medical imaging?
Digital Imaging and Communications in Medicine
Direct Imaging of Cardiovascular Anatomy in Modality
Dynamic Imaging Computerized Object Measurement
Diagnostic Imaging and Clinical Object Management
Explanation - DICOM is the standard for handling, storing, printing, and transmitting medical imaging information.
Correct answer is: Digital Imaging and Communications in Medicine
Q.12 Which imaging modality provides functional information about blood flow within the brain?
CT angiography
PET
MRI
X‑ray
Explanation - CT angiography uses contrast‑enhanced CT scans to visualize blood vessels and assess blood flow.
Correct answer is: CT angiography
Q.13 In MRI, what is the purpose of the RF (radio‑frequency) pulse?
To heat the tissue
To excite hydrogen atoms so they emit signals
To create a magnetic field
To capture X‑ray photons
Explanation - RF pulses flip the orientation of hydrogen nuclei, enabling them to emit detectable signals for image reconstruction.
Correct answer is: To excite hydrogen atoms so they emit signals
Q.14 Which imaging technique is best for assessing lung ventilation and perfusion simultaneously?
CT perfusion
MRI ventilation‑perfusion
PET‑CT
X‑ray
Explanation - MRI ventilation‑perfusion imaging can evaluate both the air and blood flow in the lungs without ionizing radiation.
Correct answer is: MRI ventilation‑perfusion
Q.15 What is the main safety concern when using ionizing radiation in imaging?
Skin irritation
Radiation-induced DNA damage
Noise pollution
Heat generation
Explanation - Ionizing radiation can break DNA strands, potentially leading to cancer or other health effects.
Correct answer is: Radiation-induced DNA damage
Q.16 Which imaging modality uses rotating gamma cameras to detect emitted photons from radiotracers?
PET
SPECT
CT
MRI
Explanation - SPECT (Single‑Photon Emission Computed Tomography) captures gamma rays emitted from radiotracers to create 3‑D images.
Correct answer is: SPECT
Q.17 Which of the following is a common contraindication for MRI scanning?
Pregnancy
Metallic implants
Asthma
Diabetes
Explanation - Strong magnetic fields can move or heat ferromagnetic implants, making them unsafe for MRI.
Correct answer is: Metallic implants
Q.18 What does the term 'slice thickness' refer to in CT imaging?
The thickness of the X‑ray beam
The width of the patient’s body
The thickness of each reconstructed image plane
The length of the scan time
Explanation - Slice thickness determines how thick each cross‑sectional image is and affects spatial resolution.
Correct answer is: The thickness of each reconstructed image plane
Q.19 Which imaging modality is primarily used to evaluate brain tumors and has high sensitivity for soft tissue contrast?
CT
Ultrasound
MRI
X‑ray
Explanation - MRI provides excellent soft‑tissue contrast and is the standard for brain tumor imaging.
Correct answer is: MRI
Q.20 What is the principle behind ultrasound imaging called?
Diffraction
Reflection
Refraction
Diffusion
Explanation - Ultrasound images are formed by reflecting sound waves off tissue interfaces and detecting the returned echoes.
Correct answer is: Reflection
Q.21 Which of the following parameters primarily determines the spatial resolution of a CT scanner?
Tube voltage (kV)
Detector size
Patient's body size
Contrast agent type
Explanation - Smaller detector elements enable finer sampling and higher spatial resolution in CT imaging.
Correct answer is: Detector size
Q.22 What is the role of gadolinium in MRI?
It provides contrast by shortening T1 relaxation time
It shields the patient from magnetic fields
It reduces noise in the image
It acts as a tracer for PET
Explanation - Gadolinium-based contrast agents alter relaxation properties, enhancing visibility of vascular structures or lesions.
Correct answer is: It provides contrast by shortening T1 relaxation time
Q.23 In PET imaging, what does the term 'SUV' stand for?
Standard Uptake Value
Serial Uptake Variable
Signal Uptake Value
Scan Uptake Value
Explanation - SUV quantifies the uptake of radiotracer in tissue relative to injected dose and body weight.
Correct answer is: Standard Uptake Value
Q.24 Which imaging modality uses a rotating gamma camera and requires the patient to remain still for several minutes?
SPECT
PET
CT
Ultrasound
Explanation - SPECT imaging acquires gamma photons over multiple angles, producing 3‑D reconstructions while the patient remains still.
Correct answer is: SPECT
Q.25 Why are CT scans often preferred for trauma patients?
They use no radiation
They are fast and provide detailed bone imaging
They are cheaper than MRI
They use contrast agents for all patients
Explanation - CT scanners can acquire complete images in seconds, making them ideal for rapid trauma assessment.
Correct answer is: They are fast and provide detailed bone imaging
Q.26 What is the main advantage of using a 3‑T MRI scanner over a 1.5‑T scanner?
Lower cost
Higher signal‑to‑noise ratio
Shorter scan times only
No need for contrast agents
Explanation - A higher magnetic field strength increases signal, improving image quality and reducing noise.
Correct answer is: Higher signal‑to‑noise ratio
Q.27 Which of these is a primary factor contributing to the dose of radiation in a CT scan?
Patient's body temperature
Tube current (mA)
Ambient lighting
Room ventilation
Explanation - The tube current controls the amount of X‑ray photons produced; higher mA results in higher patient dose.
Correct answer is: Tube current (mA)
Q.28 What is 'kV' in CT imaging terminology?
Kilovoltage, the potential difference driving the X‑ray tube
Kilovolt, the number of X‑ray photons
Kilo‑volume, the size of the detector array
Kilo‑variable, a software parameter
Explanation - kV determines the energy of emitted X‑ray photons, affecting penetration and contrast.
Correct answer is: Kilovoltage, the potential difference driving the X‑ray tube
Q.29 Which imaging modality is commonly used for functional brain imaging during a task?
PET
fMRI
CT
X‑ray
Explanation - Functional MRI detects changes in blood oxygenation associated with neural activity during tasks.
Correct answer is: fMRI
Q.30 What is a major limitation of using PET for imaging small lesions?
High radiation dose
Low spatial resolution compared to CT
Invasive procedure
Long scan times
Explanation - PET typically has lower spatial resolution, making small lesions difficult to detect.
Correct answer is: Low spatial resolution compared to CT
Q.31 Which of the following best describes 'phase‑contrast CT'?
Uses phases of the cardiac cycle for imaging
Detects differences in X‑ray phase shifts for soft tissue contrast
Imaging during different phases of respiration
A type of PET scan
Explanation - Phase‑contrast CT uses phase information from X‑ray wavefronts to improve visualization of soft tissues.
Correct answer is: Detects differences in X‑ray phase shifts for soft tissue contrast
Q.32 Which contrast agent is contraindicated in patients with severe renal impairment?
Gadolinium
Iodinated contrast
Barium sulfate
Ultrasound gel
Explanation - Iodinated contrast can worsen renal function; gadolinium is also risky but mainly for nephrogenic systemic fibrosis.
Correct answer is: Iodinated contrast
Q.33 What does the term 'temporal resolution' refer to in cardiac MRI?
The number of slices per second
The speed at which the heart can be imaged during one cardiac cycle
The resolution of the image in the time dimension
The resolution of the image in the spatial dimension
Explanation - Temporal resolution describes how quickly images can capture the moving heart, essential for motion‑free imaging.
Correct answer is: The speed at which the heart can be imaged during one cardiac cycle
Q.34 Which of the following is a typical artifact in MRI caused by patient motion?
Beam hardening
Susceptibility artifact
Motion blur
Streak artifact
Explanation - Patient movement during acquisition smears image signals, resulting in motion blur artifacts.
Correct answer is: Motion blur
Q.35 What is the purpose of a 'shutter' in a CT scanner?
To protect the patient from noise
To limit the exposure to radiation
To focus the X‑ray beam
To cool the X‑ray tube
Explanation - The shutter can reduce beam exposure to specific areas, decreasing radiation dose.
Correct answer is: To limit the exposure to radiation
Q.36 What does 'kV' influence in CT imaging?
Contrast between tissues
Patient dose
Detector sensitivity
Magnetic field strength
Explanation - Higher kV increases photon energy, reducing contrast but improving penetration and reducing dose.
Correct answer is: Contrast between tissues
Q.37 Which imaging technique uses magnetic field gradients to spatially encode the MR signal?
CT
Ultrasound
MRI
PET
Explanation - Spatial encoding in MRI is achieved by applying gradient fields to differentiate signal locations.
Correct answer is: MRI
Q.38 In PET imaging, what does 'attenuation correction' account for?
Patient movement
Photon loss due to absorption in tissue
Variations in detector sensitivity
Signal noise
Explanation - Attenuation correction compensates for the loss of detected photons as they pass through different tissues.
Correct answer is: Photon loss due to absorption in tissue
Q.39 Which imaging modality is most suitable for evaluating bone healing after fracture?
MRI
CT
Ultrasound
X‑ray
Explanation - X‑ray provides clear images of bone remodeling and fracture union over time.
Correct answer is: X‑ray
Q.40 What is a key advantage of using a 7‑T MRI scanner in research settings?
Lower cost
Higher signal-to-noise ratio
Simpler imaging protocols
Reduced scan time for all patients
Explanation - 7‑T scanners provide higher field strength, improving resolution and signal quality for detailed imaging.
Correct answer is: Higher signal-to-noise ratio
Q.41 Which parameter in CT imaging directly affects the level of image noise?
Detector size
Tube voltage (kV)
Patient age
Scanner manufacturer
Explanation - Lower kV increases image noise, while higher kV reduces noise but also reduces contrast.
Correct answer is: Tube voltage (kV)
Q.42 What is the primary safety concern with gadolinium‑based contrast agents in patients with kidney disease?
Allergic reaction
Nephrogenic systemic fibrosis
Radiation exposure
Heat generation
Explanation - Gadolinium can cause a rare but serious skin and connective tissue disease in patients with severe kidney dysfunction.
Correct answer is: Nephrogenic systemic fibrosis
Q.43 In MRI, what is 'echo time' (TE) related to?
Signal intensity of T1-weighted images
Time between successive RF pulses
Time between excitation and signal readout
Field strength of the magnet
Explanation - TE influences image contrast and is the delay between excitation and signal detection.
Correct answer is: Time between excitation and signal readout
Q.44 What imaging technique provides functional imaging of glucose metabolism in the brain?
PET with FDG
CT
MRI
Ultrasound
Explanation - Fluorodeoxyglucose (FDG) PET maps glucose uptake, revealing metabolic activity.
Correct answer is: PET with FDG
Q.45 Which of the following is a typical application of diffusion‑weighted MRI (DWI)?
Assessing bone mineral density
Detecting acute ischemic stroke
Measuring lung function
Imaging gastrointestinal tract
Explanation - DWI is highly sensitive to water diffusion changes that occur early in ischemic stroke.
Correct answer is: Detecting acute ischemic stroke
Q.46 What is the main advantage of using dual‑energy CT?
Lower radiation dose
Improved material differentiation
Faster scanning time
Higher spatial resolution
Explanation - Dual‑energy CT uses two X‑ray spectra to better distinguish between tissues or contrast agents.
Correct answer is: Improved material differentiation
Q.47 Which of the following best describes a 'phantom' in medical imaging?
A type of tumor model
An artificial object used to calibrate and test imaging devices
A rare imaging artifact
A specific imaging technique
Explanation - Phantoms simulate human tissues to evaluate image quality and system performance.
Correct answer is: An artificial object used to calibrate and test imaging devices
Q.48 In CT imaging, what does the term 'pitch' refer to?
Speed of the X‑ray tube rotation
Overlapping of consecutive slices
Distance the table moves per rotation relative to slice thickness
Angle of the patient table
Explanation - Pitch determines how quickly the scanner acquires data and impacts image resolution and dose.
Correct answer is: Distance the table moves per rotation relative to slice thickness
Q.49 What does the acronym DICOM stand for?
Digital Imaging and Communications in Medicine
Direct Imaging of Computerized Medical
Diagnostic Imaging Communication in Modality
Digital Interface for Computerized Medical
Explanation - DICOM is the standard for handling, storing, and transmitting medical imaging information.
Correct answer is: Digital Imaging and Communications in Medicine
Q.50 Which imaging modality uses gamma cameras to detect photons emitted from radiotracers?
CT
PET
MRI
SPECT
Explanation - SPECT scanners rotate gamma cameras around the patient to reconstruct 3‑D images from emitted photons.
Correct answer is: SPECT
Q.51 Which of the following best describes the principle of X‑ray attenuation in CT imaging?
Higher energy photons are absorbed more
Lower energy photons are absorbed more
All photons are absorbed equally
Photons are reflected rather than absorbed
Explanation - Lower energy X‑rays are absorbed more strongly by dense tissues, creating contrast.
Correct answer is: Lower energy photons are absorbed more
Q.52 What is the primary safety concern when using ionizing radiation in pediatric imaging?
High risk of allergic reaction
Higher sensitivity to radiation-induced cancer
Longer scan times
Poor image quality
Explanation - Children are more radiosensitive, so dose optimization is critical to reduce lifetime cancer risk.
Correct answer is: Higher sensitivity to radiation-induced cancer
Q.53 Which of the following is NOT a type of MRI contrast mechanism?
T1 relaxation
T2 relaxation
Diffusion weighting
Gamma decay
Explanation - Gamma decay is related to nuclear physics, not MRI signal generation.
Correct answer is: Gamma decay
Q.54 Which imaging modality uses high‑frequency sound waves to produce images of soft tissues?
MRI
CT
Ultrasound
X‑ray
Explanation - Ultrasound imaging relies on sound waves reflecting from tissue interfaces to create images.
Correct answer is: Ultrasound
Q.55 In MRI, what does 'TR' (repetition time) affect?
Contrast of T2-weighted images
Contrast of T1-weighted images
Spatial resolution
Magnetic field strength
Explanation - TR influences T1 weighting; shorter TR gives higher T1 contrast.
Correct answer is: Contrast of T1-weighted images
Q.56 Which of the following best explains the term 'beam hardening' in CT?
The X‑ray beam becomes softer as it passes through tissue
The X‑ray beam loses energy, affecting image uniformity
The beam becomes harder, leading to increased contrast
The beam is hardened by the patient's body
Explanation - Beam hardening occurs when low‑energy photons are absorbed more, changing beam composition and causing artifacts.
Correct answer is: The X‑ray beam loses energy, affecting image uniformity
Q.57 What is the main advantage of using a 3‑D reconstruction in MRI?
It eliminates the need for contrast agents
It allows visualization of structures from multiple angles
It reduces scan time
It increases magnetic field strength
Explanation - 3‑D reconstruction provides volumetric data that can be viewed from any orientation.
Correct answer is: It allows visualization of structures from multiple angles
Q.58 Which of the following is a major source of image noise in MRI?
Ambient lighting
Patient motion
Ambient temperature
Room ventilation
Explanation - Patient movement blurs the MR signal, causing noise and artifacts in the image.
Correct answer is: Patient motion
Q.59 What is the purpose of using a 'shutter' in a CT scanner?
To control beam intensity on specific patient areas
To cool the X‑ray tube
To focus the X‑ray beam
To shield the operator from radiation
Explanation - A shutter can reduce radiation exposure to targeted parts of the patient’s body.
Correct answer is: To control beam intensity on specific patient areas
Q.60 Which imaging modality is best for detecting early bone microfractures?
X‑ray
MRI
CT
Ultrasound
Explanation - MRI provides high contrast for bone marrow edema, which indicates early microfractures.
Correct answer is: MRI
Q.61 Which of the following is a major advantage of PET imaging over CT?
Higher spatial resolution
Functional information about metabolic activity
No radiation exposure
Lower cost
Explanation - PET measures biological processes, while CT mainly provides anatomical detail.
Correct answer is: Functional information about metabolic activity
Q.62 What is a common contraindication for the use of gadolinium‑based contrast agents?
Pregnancy
Allergy to iodine
Kidney disease
Asthma
Explanation - Reduced renal function increases the risk of nephrogenic systemic fibrosis after gadolinium exposure.
Correct answer is: Kidney disease
Q.63 Which imaging modality uses high‑frequency acoustic waves to produce images of the body's interior?
MRI
X‑ray
Ultrasound
PET
Explanation - Ultrasound imaging relies on acoustic waves to detect tissue interfaces.
Correct answer is: Ultrasound
Q.64 Which of the following is a benefit of using dual‑energy CT?
Lower radiation dose
Better tissue differentiation
Simpler image reconstruction
Reduced scan time
Explanation - Dual‑energy CT acquires data at two energy levels, improving material identification.
Correct answer is: Better tissue differentiation
Q.65 What does the term 'kV' represent in CT imaging?
Kilovoltage, the X‑ray tube potential
Kilo‑volume of the detector array
Kilovolt of the magnetic field
Kilo‑variable of the scanner
Explanation - kV determines the energy of X‑ray photons, influencing penetration and contrast.
Correct answer is: Kilovoltage, the X‑ray tube potential
Q.66 Which imaging modality provides the highest spatial resolution for small anatomical structures?
PET
MRI
CT
Ultrasound
Explanation - MRI offers high spatial resolution, especially for soft tissue detail.
Correct answer is: MRI
Q.67 What does 'slice thickness' influence in CT imaging?
Image noise level
Radiation dose
Temporal resolution
Spatial resolution
Explanation - Thinner slices improve spatial resolution but increase noise and dose.
Correct answer is: Spatial resolution
Q.68 In MRI, what does 'echo time' (TE) influence?
T1 weighting
T2 weighting
Diffusion weighting
Spatial resolution
Explanation - TE controls the degree of T2 contrast in MR images.
Correct answer is: T2 weighting
Q.69 What is the primary function of a collimator in a CT scanner?
To reduce patient motion
To shape the X‑ray beam
To cool the X‑ray tube
To increase image contrast
Explanation - Collimators limit the X‑ray beam to the area of interest, reducing scatter and dose.
Correct answer is: To shape the X‑ray beam
Q.70 Which imaging modality uses a rotating gamma camera to capture photons emitted from radiotracers?
PET
CT
MRI
SPECT
Explanation - SPECT employs a rotating gamma camera to detect photons emitted by radiotracers for 3‑D reconstruction.
Correct answer is: SPECT
Q.71 What does the 'pitch' parameter control in a CT scanner?
Table speed relative to slice thickness
Beam intensity
Patient positioning
Image contrast
Explanation - Pitch determines how quickly the scanner acquires data and affects image resolution and dose.
Correct answer is: Table speed relative to slice thickness
Q.72 Which of the following is a common artifact in CT imaging caused by metallic objects?
Beam hardening
Motion blur
Streak artifact
Ring artifact
Explanation - Metallic objects create streaks due to high attenuation and beam hardening.
Correct answer is: Streak artifact
Q.73 What is the main advantage of using a 7‑T MRI scanner?
Lower cost
Higher signal‑to‑noise ratio
Simpler protocols
Reduced scan time for all patients
Explanation - Higher field strength increases signal and improves image quality.
Correct answer is: Higher signal‑to‑noise ratio
Q.74 Which imaging modality is most suitable for monitoring the progression of bone healing?
X‑ray
MRI
CT
Ultrasound
Explanation - X‑ray provides clear images of bone remodeling over time.
Correct answer is: X‑ray
Q.75 Which imaging technique uses magnetic fields and radiofrequency pulses to visualize anatomical structures?
X‑ray
CT
MRI
Ultrasound
Explanation - MRI relies on magnetic fields and RF pulses to image tissues.
Correct answer is: MRI
Q.76 Which of the following best describes the principle of diffusion‑weighted MRI?
It measures the diffusion of water molecules within tissue
It measures the diffusion of X‑ray photons
It measures the diffusion of magnetic fields
It measures the diffusion of radiofrequency energy
Explanation - Diffusion‑weighted imaging detects changes in the movement of water molecules.
Correct answer is: It measures the diffusion of water molecules within tissue
Q.77 In PET imaging, what does the term 'SUV' stand for?
Standard Uptake Value
Serial Uptake Variable
Signal Uptake Value
Scan Uptake Value
Explanation - SUV quantifies the uptake of radiotracer relative to injected dose and body weight.
Correct answer is: Standard Uptake Value
Q.78 Which imaging modality is commonly used to diagnose acute pulmonary embolism?
CT pulmonary angiography
MRI
PET
Ultrasound
Explanation - CT pulmonary angiography visualizes pulmonary arteries and detects emboli.
Correct answer is: CT pulmonary angiography
Q.79 What is the main advantage of using dual‑energy CT compared to single‑energy CT?
Reduced radiation dose
Improved tissue contrast
Simplified reconstruction
Lower cost
Explanation - Dual‑energy CT provides better differentiation of tissues using two different X‑ray spectra.
Correct answer is: Improved tissue contrast
Q.80 Which imaging modality provides functional information about the heart’s electrical activity?
CT
MRI
X‑ray
ECG
Explanation - Electrocardiography (ECG) records the heart’s electrical signals, not an image.
Correct answer is: ECG
Q.81 What does 'temporal resolution' refer to in cardiac imaging?
Spatial resolution of the image
Ability to capture rapid motion
Duration of the entire scan
Level of contrast between tissues
Explanation - Temporal resolution measures how fast images can be acquired to freeze motion.
Correct answer is: Ability to capture rapid motion
Q.82 Which imaging modality uses ionizing radiation to create detailed images of bone and soft tissue?
MRI
X‑ray
Ultrasound
PET
Explanation - X‑ray imaging uses ionizing radiation for high‑contrast images of bone.
Correct answer is: X‑ray
Q.83 Which of the following is a common contraindication for MRI?
Pregnancy
Metallic implants
Asthma
Hypertension
Explanation - Ferromagnetic implants can move or heat in the magnetic field, posing a safety risk.
Correct answer is: Metallic implants
Q.84 What imaging technique is primarily used to evaluate the structure of the brain’s white matter?
PET
CT
MRI
X‑ray
Explanation - MRI provides detailed images of white matter due to its excellent soft‑tissue contrast.
Correct answer is: MRI
Q.85 Which of the following best describes the use of a 'shutter' in a CT scanner?
To protect the operator from radiation
To focus the X‑ray beam
To limit beam exposure to specific areas
To cool the X‑ray tube
Explanation - A shutter can reduce radiation dose by restricting the beam to the region of interest.
Correct answer is: To limit beam exposure to specific areas
Q.86 In MRI, what does the 'TR' (repetition time) control?
The time between successive RF pulses
The time between excitation and signal readout
The field strength
The spatial resolution
Explanation - TR determines the interval between successive excitations, influencing image contrast.
Correct answer is: The time between successive RF pulses
Q.87 What is the purpose of using a 'phantom' in medical imaging?
To mimic patient anatomy for calibration
To treat patients
To reduce radiation dose
To create contrast agents
Explanation - Phantoms are artificial objects used to test and calibrate imaging systems.
Correct answer is: To mimic patient anatomy for calibration
Q.88 Which imaging modality provides the highest contrast for soft tissues?
CT
X‑ray
MRI
Ultrasound
Explanation - MRI’s strong magnetic field and radiofrequency pulses produce excellent soft‑tissue contrast.
Correct answer is: MRI
Q.89 What is the primary safety concern with ionizing radiation in medical imaging?
Risk of infection
Potential for radiation-induced cancer
Noise pollution
Heat generation
Explanation - Ionizing radiation can damage DNA, increasing the risk of cancer.
Correct answer is: Potential for radiation-induced cancer
Q.90 Which imaging modality is used to evaluate the blood supply to the brain?
CT angiography
X‑ray
MRI
Ultrasound
Explanation - CT angiography visualizes blood vessels after contrast injection.
Correct answer is: CT angiography
Q.91 What does 'kV' in CT imaging affect?
Image contrast
Patient dose
Detector sensitivity
Magnetic field strength
Explanation - Higher kV reduces image contrast but improves penetration and reduces dose.
Correct answer is: Image contrast
Q.92 Which of the following best describes the term 'beam hardening' in CT imaging?
The X‑ray beam becomes harder as it passes through tissue
The beam loses energy, affecting image uniformity
The beam becomes harder, leading to increased contrast
The beam is hardened by the patient’s body
Explanation - Beam hardening occurs when low‑energy photons are absorbed, changing beam composition.
Correct answer is: The beam loses energy, affecting image uniformity
Q.93 Which imaging modality uses a rotating gamma camera to detect photons emitted from radiotracers?
PET
CT
MRI
SPECT
Explanation - SPECT scanners rotate gamma cameras around the patient to capture emitted photons.
Correct answer is: SPECT
Q.94 What does the term 'pitch' in CT scanning refer to?
The speed of the X‑ray tube rotation
The overlap of consecutive slices
The distance the table moves per rotation relative to slice thickness
The angle of the patient table
Explanation - Pitch affects image resolution, dose, and acquisition time.
Correct answer is: The distance the table moves per rotation relative to slice thickness
Q.95 Which of the following is a major advantage of PET imaging?
High spatial resolution
Functional information on metabolic activity
No radiation exposure
Lower cost
Explanation - PET provides metabolic and functional data, not just anatomical detail.
Correct answer is: Functional information on metabolic activity
Q.96 What is the main advantage of using a 7‑T MRI scanner?
Lower cost
Higher signal‑to‑noise ratio
Simpler protocols
Reduced scan time for all patients
Explanation - Higher field strength increases signal and improves image quality.
Correct answer is: Higher signal‑to‑noise ratio
Q.97 Which imaging modality is most suitable for evaluating bone fractures?
MRI
Ultrasound
CT
X‑ray
Explanation - X‑ray imaging provides clear bone images, ideal for fracture assessment.
Correct answer is: X‑ray
Q.98 What type of imaging device uses sound waves to create pictures?
X‑ray
Ultrasound
MRI
CT scan
Explanation - Ultrasound imaging employs high‑frequency sound waves.
Correct answer is: Ultrasound
Q.99 Which of the following imaging modalities uses ionizing radiation?
MRI
CT
Ultrasound
PET
Explanation - CT scanners use X‑ray beams, a form of ionizing radiation.
Correct answer is: CT
Q.100 Which imaging technique is considered the gold standard for visualizing brain tumors?
CT
X‑ray
MRI
Ultrasound
Explanation - MRI provides the best soft‑tissue contrast for brain tumors.
Correct answer is: MRI
Q.101 In MRI, what is the role of the RF pulse?
To heat tissues
To excite hydrogen nuclei for signal emission
To create an X‑ray beam
To cool the magnet
Explanation - RF pulses flip hydrogen nuclei, enabling them to emit detectable signals.
Correct answer is: To excite hydrogen nuclei for signal emission
Q.102 Which imaging modality is best for visualizing soft tissues without radiation?
X‑ray
CT
Ultrasound
PET
Explanation - Ultrasound uses sound waves, not ionizing radiation.
Correct answer is: Ultrasound
Q.103 What does PET stand for?
Positron Emission Tomography
Photon Emission Tomography
Polymer Electron Transmission
Polarized Energy Test
Explanation - PET uses positron‑emitting radiotracers to image metabolic processes.
Correct answer is: Positron Emission Tomography
Q.104 Which imaging modality uses a rotating X‑ray source and detector to create a 3‑D image?
CT
MRI
Ultrasound
X‑ray
Explanation - CT scanners rotate around the patient, gathering multiple projections for reconstruction.
Correct answer is: CT
Q.105 Which of these is NOT a type of contrast agent used in medical imaging?
Iodinated contrast
Gadolinium
Barium sulfate
Water
Explanation - Water is not a contrast agent; it does not enhance imaging contrast.
Correct answer is: Water
Q.106 Which imaging technique can be performed quickly to check for a broken bone?
PET
CT
X‑ray
MRI
Explanation - X‑ray imaging is fast and effective for detecting fractures.
Correct answer is: X‑ray
Q.107 In which imaging modality is a magnetic field used to align atoms in the body?
CT
MRI
X‑ray
Ultrasound
Explanation - MRI uses a magnetic field to align hydrogen nuclei before detecting signals.
Correct answer is: MRI
Q.108 What is the main advantage of PET imaging over conventional X‑ray imaging?
Higher spatial resolution
Functional information about metabolism
No need for contrast agents
Lower cost
Explanation - PET shows metabolic activity, whereas X‑ray shows anatomy only.
Correct answer is: Functional information about metabolism
Q.109 Which imaging modality is most suitable for diagnosing a pulmonary embolism?
CT pulmonary angiography
MRI
X‑ray
Ultrasound
Explanation - CT pulmonary angiography visualizes the pulmonary arteries to detect emboli.
Correct answer is: CT pulmonary angiography
Q.110 What is a common contraindication for using gadolinium‑based contrast agents?
Pregnancy
Kidney disease
Asthma
Diabetes
Explanation - Kidney disease increases the risk of nephrogenic systemic fibrosis after gadolinium exposure.
Correct answer is: Kidney disease
Q.111 Which imaging modality uses gamma cameras to detect photons emitted by radiotracers?
PET
CT
MRI
SPECT
Explanation - SPECT scanners rotate a gamma camera around the patient to acquire data.
Correct answer is: SPECT
Q.112 What does 'kV' stand for in CT imaging?
Kilovoltage
Kilo‑volume
Kilovolt
Kilo‑variable
Explanation - kV determines the energy of X‑ray photons.
Correct answer is: Kilovoltage
Q.113 Which imaging modality provides the highest contrast for soft tissues?
CT
MRI
X‑ray
Ultrasound
Explanation - MRI offers excellent soft‑tissue contrast due to its magnetic field and RF pulses.
Correct answer is: MRI
Q.114 Which of the following is a typical artifact in MRI caused by metallic implants?
Beam hardening
Motion blur
Susceptibility artifact
Ring artifact
Explanation - Metallic implants cause local magnetic field distortions, resulting in artifacts.
Correct answer is: Susceptibility artifact
Q.115 What is the purpose of the 'shutter' in a CT scanner?
To focus the X‑ray beam
To reduce beam exposure to specific areas
To cool the X‑ray tube
To shield the operator from radiation
Explanation - The shutter limits the X‑ray beam, reducing dose to non‑target tissues.
Correct answer is: To reduce beam exposure to specific areas
Q.116 Which imaging modality uses a rotating gamma camera to capture photons emitted from radiotracers?
PET
SPECT
CT
MRI
Explanation - SPECT acquires gamma photons from radiotracers using a rotating camera.
Correct answer is: SPECT
Q.117 What is the main safety concern when using ionizing radiation in medical imaging?
Noise pollution
Radiation-induced DNA damage
Heat generation
Skin irritation
Explanation - Ionizing radiation can damage DNA, potentially leading to cancer.
Correct answer is: Radiation-induced DNA damage
Q.118 Which imaging modality is best for diagnosing a fractured wrist?
CT
X‑ray
MRI
Ultrasound
Explanation - X‑ray imaging provides clear bone detail for fracture assessment.
Correct answer is: X‑ray
Q.119 Which imaging modality is most suitable for detecting early lung cancer?
MRI
CT
X‑ray
Ultrasound
Explanation - Low‑dose CT scans can detect small lung nodules early.
Correct answer is: CT
Q.120 What imaging modality uses a strong magnetic field and radio waves?
MRI
X‑ray
CT
Ultrasound
Explanation - MRI employs magnetic fields and RF pulses for imaging.
Correct answer is: MRI
Q.121 Which imaging technique provides functional information about glucose metabolism?
CT
PET with FDG
X‑ray
Ultrasound
Explanation - FDG PET images glucose uptake, indicating metabolic activity.
Correct answer is: PET with FDG
Q.122 Which of the following is a major advantage of dual‑energy CT?
Reduced radiation dose
Improved tissue differentiation
Simpler reconstruction
Lower cost
Explanation - Dual‑energy CT uses two energy spectra for better material identification.
Correct answer is: Improved tissue differentiation
Q.123 What is a typical artifact in CT imaging caused by metal objects?
Beam hardening
Streak artifact
Motion blur
Ring artifact
Explanation - Metal causes streaks due to high attenuation and beam hardening.
Correct answer is: Streak artifact
Q.124 Which imaging modality uses a rotating X‑ray source to obtain cross‑sectional images?
CT
MRI
Ultrasound
X‑ray
Explanation - CT scanners rotate the X‑ray tube and detectors around the patient.
Correct answer is: CT
Q.125 What does the acronym DICOM stand for?
Digital Imaging and Communications in Medicine
Direct Imaging of Computerized Medicine
Diagnostic Imaging Communication in Modality
Digital Interface for Computerized Medicine
Explanation - DICOM is the standard for medical imaging data exchange.
Correct answer is: Digital Imaging and Communications in Medicine
Q.126 Which imaging modality provides the highest spatial resolution for small anatomical structures?
CT
MRI
PET
Ultrasound
Explanation - MRI offers high spatial resolution for soft tissues.
Correct answer is: MRI
Q.127 What is the main benefit of using a 3‑D reconstruction in MRI?
Simplifies image acquisition
Provides volumetric data from any orientation
Reduces radiation exposure
Increases magnet field strength
Explanation - 3‑D MRI gives volumetric information for multi‑plane viewing.
Correct answer is: Provides volumetric data from any orientation
Q.128 What does the term 'beam hardening' refer to in CT imaging?
The X‑ray beam becoming more energetic after passing through tissue
The reduction in X‑ray beam intensity due to absorption
The beam gaining energy from the patient
The beam becoming harder to detect
Explanation - Low‑energy photons are absorbed, leaving a harder beam that can cause artifacts.
Correct answer is: The X‑ray beam becoming more energetic after passing through tissue
Q.129 Which imaging modality uses a strong magnetic field to align hydrogen atoms and detect their signals?
CT
X‑ray
MRI
PET
Explanation - MRI uses magnetic fields to align hydrogen nuclei for signal detection.
Correct answer is: MRI
Q.130 Which imaging modality is best suited for evaluating soft tissue structures in the brain?
X‑ray
CT
MRI
Ultrasound
Explanation - MRI provides excellent soft‑tissue contrast for brain imaging.
Correct answer is: MRI
Q.131 Which imaging modality uses radioisotopes to provide functional information about the body?
CT
X‑ray
PET
Ultrasound
Explanation - PET uses radiotracers that emit positrons for metabolic imaging.
Correct answer is: PET
Q.132 What is the main advantage of a 7‑T MRI scanner compared to a 3‑T scanner?
Lower cost
Higher signal‑to‑noise ratio
Shorter scan times
Simpler protocols
Explanation - Higher field strength increases signal and image quality.
Correct answer is: Higher signal‑to‑noise ratio
Q.133 Which of the following best describes 'diffusion‑weighted imaging' in MRI?
It measures the diffusion of X‑ray photons
It measures the diffusion of water molecules within tissue
It measures the diffusion of magnetic fields
It measures the diffusion of radiofrequency energy
Explanation - Diffusion weighting detects changes in water movement, useful for early stroke imaging.
Correct answer is: It measures the diffusion of water molecules within tissue
Q.134 Which imaging modality is used to monitor the progression of bone healing?
X‑ray
MRI
CT
Ultrasound
Explanation - Serial X‑ray images track bone remodeling during healing.
Correct answer is: X‑ray
Q.135 What is a major safety concern when using gadolinium‑based contrast agents in patients with kidney disease?
Allergic reaction
Nephrogenic systemic fibrosis
Radiation exposure
Heat generation
Explanation - Reduced kidney function increases risk of NSF after gadolinium exposure.
Correct answer is: Nephrogenic systemic fibrosis
Q.136 Which imaging modality is best for detecting early bone microfractures?
MRI
CT
X‑ray
Ultrasound
Explanation - MRI can show bone marrow edema associated with microfractures.
Correct answer is: MRI
Q.137 Which imaging technique uses gamma cameras to detect photons emitted by radiotracers?
PET
SPECT
CT
MRI
Explanation - SPECT scanners rotate a gamma camera around the patient to acquire data.
Correct answer is: SPECT
Q.138 What does the term 'kV' refer to in CT imaging?
Kilovoltage
Kilo‑volume
Kilovolt
Kilo‑variable
Explanation - kV determines the energy of X‑ray photons.
Correct answer is: Kilovoltage
Q.139 Which of the following imaging modalities uses sound waves to visualize internal structures?
X‑ray
CT
MRI
Ultrasound
Explanation - Ultrasound relies on sound wave reflections.
Correct answer is: Ultrasound
Q.140 What is the main purpose of using a contrast agent in MRI?
Reduce the scan time
Increase the strength of the magnetic field
Improve image contrast by altering relaxation times
Prevent patient motion
Explanation - Contrast agents like gadolinium shorten T1 relaxation, enhancing tissue contrast.
Correct answer is: Improve image contrast by altering relaxation times
Q.141 Which imaging modality is the gold standard for detecting breast cancer?
X‑ray mammography
CT
MRI
Ultrasound
Explanation - Mammography uses low‑dose X‑rays for early breast cancer detection.
Correct answer is: X‑ray mammography
Q.142 In PET imaging, what does the 'SUV' represent?
Standard Uptake Value
Signal Uptake Volume
Serial Uptake Value
Scan Uptake Value
Explanation - SUV quantifies radiotracer uptake relative to dose and body weight.
Correct answer is: Standard Uptake Value
Q.143 Which imaging modality is best for detecting small lung nodules?
CT
MRI
X‑ray
Ultrasound
Explanation - Low‑dose CT can detect small pulmonary nodules early.
Correct answer is: CT
Q.144 What is a common artifact in MRI caused by metallic implants?
Beam hardening
Motion blur
Susceptibility artifact
Ring artifact
Explanation - Metal alters local magnetic fields, producing artifacts.
Correct answer is: Susceptibility artifact
Q.145 Which imaging modality uses a rotating gamma camera to detect emitted photons?
SPECT
CT
MRI
PET
Explanation - SPECT scanners rotate gamma cameras to acquire 3‑D data.
Correct answer is: SPECT
Q.146 What is the main advantage of using PET over CT in oncology?
Higher spatial resolution
Functional metabolic imaging
No radiation exposure
Lower cost
Explanation - PET shows tumor metabolism, aiding in early detection and treatment planning.
Correct answer is: Functional metabolic imaging
Q.147 Which imaging modality provides the highest contrast for bone structures?
CT
X‑ray
MRI
Ultrasound
Explanation - CT’s high spatial resolution makes it ideal for bone imaging.
Correct answer is: CT
Q.148 What is a primary benefit of using a 7‑T MRI scanner?
Lower cost
Higher signal‑to‑noise ratio
Simpler protocols
Reduced scan times for all patients
Explanation - Higher field strength improves signal and image quality.
Correct answer is: Higher signal‑to‑noise ratio
Q.149 Which imaging modality is most commonly used to evaluate the heart’s anatomy and function?
CT
MRI
X‑ray
Ultrasound
Explanation - MRI offers excellent cardiac anatomy and functional imaging without radiation.
Correct answer is: MRI
Q.150 Which of the following imaging modalities uses ionizing radiation to produce images?
MRI
PET
X‑ray
Ultrasound
Explanation - X‑ray, CT, and PET all use ionizing radiation; MRI and ultrasound do not.
Correct answer is: X‑ray
Q.151 Which imaging technique can be used to monitor the progression of multiple sclerosis?
MRI
CT
X‑ray
Ultrasound
Explanation - MRI provides detailed images of brain and spinal cord lesions.
Correct answer is: MRI
Q.152 Which of these is a common contraindication for MRI?
Pregnancy
Metallic implants
Asthma
Diabetes
Explanation - Ferromagnetic implants can move or heat in the magnetic field.
Correct answer is: Metallic implants
Q.153 What is the main advantage of using a 7‑T MRI scanner?
Lower cost
Higher signal‑to‑noise ratio
Simpler protocols
Reduced scan times
Explanation - Higher field strength improves signal quality and resolution.
Correct answer is: Higher signal‑to‑noise ratio