← Combined Technical (NG)
Past Questions — 2026
HRCT lungs require which algorithm?
A)
Soft tissue
B)
Bone/ high-resolution kernel
C)
Standard
D)
Low-pass filter
HRCT (High-Resolution CT) of the lungs is reconstructed using a sharp, high-spatial-frequency algorithm, commonly called a bone or high-resolution kernel, to best show fine lung detail and interstitial changes. Soft tissue and standard kernels are too smooth and reduce edge definition, while a low-pass filter blurs fine structures, so they are not used for HRCT lung detail.
MRI works on the principle of interaction between magnetic fields and:
A)
Carbon
B)
Oxygen
C)
Hydrogen
D)
Sodium
MRI primarily works by aligning the nuclei of hydrogen atoms (protons) in the body using a strong magnetic field. When these protons are disturbed by radiofrequency pulses, they emit signals that are used to create images. Hydrogen is abundant in water and fat, making it ideal for MRI. Carbon, oxygen, and sodium are not the main basis of standard MRI imaging.
Angiography uses the following imaging principle:
A)
Xray radiation
B)
Ultrasound
C)
Long TR and Long TE Sequence
D)
Acoustic scattering
Angiography is an imaging technique used to visualize blood vessels by injecting a contrast agent and taking images with X-ray radiation (commonly called X-ray angiography). Ultrasound is used in Doppler studies, while long TR/long TE are MRI sequence parameters and acoustic scattering relates to ultrasound physics, not angiography.
Ultrasound frequency used in medical imaging is:
A)
1-20kHz
B)
20-100kHz
C)
1-20MHz
D)
50-100MHz
Medical ultrasound imaging uses frequencies in the megahertz range, typically about 1 to 20 MHz. Lower frequencies in the kHz range are below the ultrasound range or are not suitable for diagnostic imaging, while very high frequencies like 50-100 MHz are generally used only for specialized high-resolution applications with very shallow penetration. Therefore, the correct option is (c) 1-20MHz.
What is ‘road mapping’ in DSA?
A)
A 3D reconstruction of the vascular system.
B)
A tool to measure the distance between two vessels.
C)
An overlay of a mask image onto the fluoroscopic image to guide catheter placement.
D)
A technique to identify the contrast’s flow rate.
In Digital Subtraction Angiography (DSA), ‘road mapping’ means superimposing a previously acquired contrast-filled mask image on the live fluoroscopic image. This creates a visual guide of the vessels, helping the operator advance and place the catheter accurately. Option (a) is incorrect because it refers to 3D reconstruction, which is a different imaging technique. Option (b) is incorrect because road mapping is not used to measure distance. Option (d) is incorrect because it has nothing to do with determining contrast flow rate.
What type of radioactive decay is the basis for PET imaging?
A)
Alpha decay
B)
Beta-minus decay
C)
Beta-plus decay
D)
Gamma decay
PET (Positron Emission Tomography) uses radionuclides that undergo beta-plus decay, also called positron emission. The emitted positron annihilates with an electron and produces two gamma photons, which are detected by the scanner to form the image. Alpha decay does not produce positrons, beta-minus decay emits electrons, and gamma decay is not the decay basis for PET.
What is plasmin, and what is its role in thrombolysis?
A)
An inactive precursor to plasminogen.
B)
An enzyme that promotes clot formation.
C)
An enzyme that breaks down fibrin, dissolving blood clots.
D)
A substance that activates platelets.
Plasmin is the active fibrinolytic enzyme formed from plasminogen. Its main role in thrombolysis is to digest fibrin, the structural mesh of a clot, thereby dissolving the blood clot. Option (a) is incorrect because plasminogen is the inactive precursor, not plasmin. Option (b) is wrong because plasmin does not promote clot formation; it breaks clots down. Option (d) is also incorrect because platelet activation is related to clot formation, not thrombolysis.
Coil arrays are used in MRI to:
A)
To improve signal reception and image quality
B)
To change planes of scanning
C)
To enhance patient comfort
D)
To reduce scan duration
Coil arrays in MRI are used as receiver coils to detect the emitted MR signal more efficiently. By combining signals from multiple coil elements, they increase signal-to-noise ratio (SNR), which improves image quality and can also allow faster imaging. Option (b) is incorrect because scan plane selection is done by the scanner gradients, not coils. Option (c) is unrelated. Option (d) is not the primary purpose, though improved signal reception can sometimes support faster scans.
MRCP is used for the evaluation of:
A)
Renal collecting system
B)
Spleen pathology
C)
Biliary pathology
D)
Bowel pathology
MRCP stands for Magnetic Resonance Cholangiopancreatography. It is a special MRI technique used to visualize the biliary tree and pancreatic ducts, so it is mainly used for evaluating biliary pathology. It is not used for the renal collecting system, spleen pathology, or bowel pathology.
Which of the following is a common procedure for interventional radiology?
A)
Dental filling
B)
Total hip replacement
C)
Abscess pig tail drainage
D)
Heart transplant
Interventional radiology uses image-guided minimally invasive procedures for diagnosis and treatment. A common example is pigtail catheter drainage of an abscess. Dental filling, total hip replacement, and heart transplant are not interventional radiology procedures.
Which type of embolic agent is used for a temporary occlusion, such as in the management of trauma?
A)
Metallic coils
B)
Absolute ethanol
C)
Gelatin foam (Gel foam)
D)
Cyanoacrylate glue
Gelatin foam (Gelfoam) is an absorbable embolic material and is used for temporary vascular occlusion, for example in trauma or bleeding control. It is eventually resorbed by the body. Metallic coils, cyanoacrylate glue, and absolute ethanol are used for more permanent occlusion/sclerosis rather than temporary blockage.
In an Intravenous Urogram (IVU), what is the ‘nephrogram phase’?
A)
The phase where contrast is collecting in the bladder.
B)
The phase where contrast is being excreted into the ureters.
C)
The phase where contrast is concentrated within the renal parenchyma (kidney tissue).
D)
The phase where a plain radiograph (KUB) is taken before contrast injection.
In an Intravenous Urogram (IVU), the nephrogram phase is the early phase after contrast injection when the kidneys enhance and the contrast is seen in the renal parenchyma. Option (a) describes the bladder filling phase, option (b) describes the excretory/pyelographic phase with contrast in the ureters, and option (d) refers to the preliminary KUB film taken before contrast.
What is considered an absolute contraindication for a percutaneous nephrostomy procedure?
A)
Severe obesity
B)
An uncorrectable bleeding diathesis (abnormal blood coagulation)
C)
A history of kidney stones
D)
Pregnancy
Percutaneous nephrostomy is an invasive image-guided procedure, so uncontrolled coagulation problems are an absolute contraindication because they markedly increase the risk of severe bleeding. Severe obesity is a technical difficulty, not an absolute contraindication. A history of kidney stones is actually a common indication for nephrostomy in obstructive uropathy. Pregnancy is not an absolute contraindication; it requires careful radiation minimization and risk-benefit assessment.
PACS is used to store and retrieve:
A)
Patient bills
B)
Images and reports
C)
Pharmacy records
D)
OPD records
PACS stands for Picture Archiving and Communication System. It is used in radiology to store, manage, and retrieve medical images such as X-rays, CT scans, MRI scans, along with associated reports. The other options are unrelated to PACS: patient bills are handled by billing systems, pharmacy records by pharmacy management systems, and OPD records by hospital information systems.
Patient compliance for MRI is reduced due to all EXCEPT:
A)
Claustrophobia
B)
Long scanning time
C)
Loud noise
D)
Short scanning time
Patient compliance for MRI is reduced by factors that make the procedure uncomfortable or stressful, such as claustrophobia, long scanning time, and loud noise. Short scanning time does not reduce compliance; in fact, it usually improves patient tolerance. Therefore, the EXCEPT option is short scanning time.
An important component of building MRI scanning room is:
A)
RF shielding
B)
CF shielding
C)
SF shielding
D)
HF shielding
An MRI scanner produces strong radiofrequency (RF) signals and is highly sensitive to external electromagnetic interference. Therefore, an MRI scanning room must include RF shielding to prevent outside RF noise from affecting image quality and to keep MRI emissions contained. The other options are not standard shielding terms used for MRI rooms.
Which safety zone is defined as the area where the magnetic field is strong enough to pose a significant risk to unscreened individuals and ferromagnetic objects, and from which all ferromagnetic objects must be excluded?
A)
Zone I.
B)
Zone II.
C)
Zone III.
D)
Zone IV.
MRI safety zoning is commonly divided into Zones I to IV. Zone III is the area that is under the control of MRI personnel and where the magnetic field can pose a significant risk to unscreened individuals and ferromagnetic objects. Therefore, all ferromagnetic objects must be excluded from Zone III. Zone I is unrestricted public access, Zone II is the screened interface area, and Zone IV is the magnet room itself.
Which of the following best describes a flat panel detector (FPD)?
A)
An image receptor that requires a separate cassette and reader.
B)
A device that uses a vacuum tube to convert X-rays into a visible image.
C)
A solid-state detector that directly or indirectly converts X-rays into an electrical signal.
D)
A digital imaging system that relies on a CCD camera to capture an image.
A flat panel detector (FPD) is a digital radiography image receptor made of solid-state materials. It converts incoming X-rays into electrical signals either directly (e.g., amorphous selenium) or indirectly via a scintillator (e.g., cesium iodide) that first converts X-rays to light and then to electrical signal. Option (a) describes CR systems with cassette and reader, (b) refers to image intensifier/vacuum-tube based systems, and (d) describes CCD-based imaging, which is not the standard definition of an FPD.
CR uses which detector type:
A)
Direct amorphous selenium
B)
Indirect gadolinium scintillator
C)
Photostimulable phosphor plate
D)
CCD chip
Computed Radiography (CR) uses a photostimulable phosphor plate as the image receptor. The plate stores the x-ray energy and is later scanned with a laser to release light, which is converted into a digital image.
Why others are incorrect:
- Direct amorphous selenium: used in direct digital radiography (DR), not CR.
- Indirect gadolinium scintillator: also used in DR detectors.
- CCD chip: used in some older digital imaging systems, not the standard detector in CR.
What is a major disadvantage of time-of-flight (TOF) MRA, particularly in cases of high-grade stenosis?
A)
Venous contamination from the imaging volume.
B)
Inaccurate quantification of blood flow.
C)
Overestimation of the severity of stenosis due to signal loss from turbulent flow.
D)
The need for a contrast agent, which increases risk for patients with renal failure.
Time-of-flight (TOF) MRA depends on inflowing blood producing strong signal. In high-grade stenosis, blood flow becomes slower and more turbulent, which can cause signal loss (flow-related dephasing). This makes the narrowed segment look worse than it really is, so TOF MRA may overestimate the severity of stenosis. Option (a) is a limitation more associated with venous contamination in some settings, (b) is not the major classic disadvantage asked here, and (d) is incorrect because TOF MRA is typically non-contrast-based.
What is the primary purpose of an oral cholecystogram (OCG)?
A)
To assess the function of the liver.
B)
To visualize the gallbladder and assess for the presence of gallstones or other abnormalities.
C)
To image the pancreas and bile ducts simultaneously using an endoscope.
D)
To measure the contractibility of the stomach.
An oral cholecystogram (OCG) is an X-ray study in which an oral contrast medium is taken up by the liver and excreted into bile, allowing the gallbladder to be visualized. Its main purpose is to evaluate the gallbladder for gallstones, obstruction, or other structural abnormalities. Option (a) is incorrect because OCG is not primarily a liver function test. Option (c) describes endoscopic procedures like ERCP, not OCG. Option (d) is unrelated to the biliary system.
HU Hounsfield Unit of water is:
A)
+1000
B)
0
C)
– 1000
D)
+ 500
In CT imaging, the Hounsfield Unit (HU) scale is defined so that distilled water at standard conditions is assigned a value of 0 HU. By convention, air is -1000 HU and dense bone can be around +1000 HU. Therefore, the HU of water is 0, making option (b) correct. Option (a) and (d) are positive values associated with denser materials, while option (c) corresponds to air.
Mandatory patient identification before imaging is:
A)
Name and father’s name
B)
Name and age
C)
Name and registration number
D)
Name, age, registration number and confirmation from the patient
Mandatory patient identification before imaging requires using multiple identifiers and confirming with the patient to avoid wrong-patient imaging errors. Option (d) is the most complete and safest choice because it includes name, age, registration number, and direct confirmation from the patient. The other options use fewer identifiers and are therefore less reliable.
What is the role of ‘radiofrequency pulses’ in MRI?
A)
To excite the aligned hydrogen nuclei
B)
To generate the reversed electronic field
C)
To capture sonographic impulses
D)
To provide contrast enhancement
In MRI, the strong magnetic field aligns hydrogen nuclei (protons). Radiofrequency (RF) pulses then provide energy at the right frequency to excite these aligned nuclei and tip them away from equilibrium. When the RF pulse is turned off, the nuclei relax and emit signals used to form the image. Option (b) is incorrect because MRI does not use a reversed electronic field, (c) refers to ultrasound, not MRI, and (d) contrast enhancement is achieved by contrast agents, not by RF pulses themselves.
A delayed contrast reaction typically occurs within what time frame after contrast administration?
A)
Less than 1 hour.
B)
1 to 7 days.
C)
1 to 4 weeks.
D)
Immediately during injection.
Delayed contrast reactions are non-immediate hypersensitivity reactions that usually occur after 1 hour and most commonly within 1 to 7 days following contrast administration. Immediate reactions happen during injection or within the first hour, so options (a) and (d) are incorrect. Option (c) is too late for the typical delayed contrast reaction window.