Radiology represents a branch of medicine that deals with radiant energy in the diagnosis and treatment of diseases. This field can be divided into two broad areas – diagnostic radiology and interventional radiology. A physician who specializes in radiology is called radiologist.
The outcome of an imaging study does not rely merely on the indication or the quality of its technical execution. Diagnostic radiology specialist represents the last link in the diagnostic chain, as they search for relevant image information to evaluate and finally support a sound diagnosis.
The Important Questions of Radiology for NEET PG exam:
1. Threshold radiation dose for haematological syndrome is?
A. 1 Gyw
B. 5 Gy
C. 20 Gy
D. 100 Gy
Correct answer : A. 1 Gy
THRESHOLD RADIATION DOSE FOR ACUTE RADIATION SYNDROMES:
- Haematologic / haematopoietic syndrome – 1 Gy
- Gastrointestinal syndrome – 5 Gy
- Central nervous system syndrome – 20 Gy
2. Best investigation for the detection of bone metastases is?
B. CT Scan
D. Bone scan
Correct answer : D. Bone scan
BEST INVESTIGATION FOR THE DETECTION OF BONE METASTASES
- Radioisotope bone scan is the preferred method for the detection of bone metastases
- It is more sensitive than radiography for the detection of most metastases
- Technetium-99m is the commonly used radioisotope
- It accumulates in reactive new bone that is formed in the metastases resulting in a ‘hot spot‘ in the scan
- The amount of accumulation depends on the level of blood flow
- In some cases, ‘cold spots‘ are also noted due to the absence of bone formation within the lesion
- The results from a bone scan are not specific as the tracer can accumulate in other areas with increased bone formation such as sites of fracture healing / infection
- So a bone scan should be followed by other radiological modalities such as CT scan to confirm the lesion
3. Which of the following contrast agents can be used in a patient with renal dysfunction for the prevention of contrast nephropathy?
A. Low osmolar contrast
B. Ionic contrast
Correct answer : A. Low osmolar contrast
PREVENTION OF CONTRAST NEPHROPATHY
- Non ionic low osmolar contrast agents are preferred in patients with decreased renal function to prevent contrast nephropathy
- Ionic contrast media have a higher risk for contrast nephropathy, and hence should be avoided
- The amount of contrast media used should be limited
- The patient should be well hydrated before the procedure
- Supplementary interventions include use of N-acetylcysteine, fenoldopam, theophylline, prostaglandins and magnesium
4. Egg on side appearance is characteristic of?
A. Tetralogy of fallot
B. Total anomalous pulmonary venous connection
C. Patent ductus arteriosus
D. Transposition of great arteries
Correct answer : D. Transposition of great arteries
‘Egg on side’ or ‘Egg on string’ appearance is characteristic of transposition of great arteries.
5. Most ionizing radiation among the following is?
A. X rays
B. Gamma rays
C. Alpha rays
D. Beta rays
Correct answer : C. Alpha rays
Alpha rays have the highest ionization power, whereas gamma rays have the highest penetration power.
6. Which of the following substances are used to coat the walls of a CT scan room for radiation shielding?
Correct answer : C. Lead
Lead is used as radiation shielding in CT scans, X-ray machines etc.
7. Which one of the following tumors shows calcification on CT Scan:
D. CNS lymphoma
Correct answer : C. Meningioma
Both meningioma and ependymoma show calcification. But it is more common in meningioma.
8. Which one of the following is the most preferred route to perform cerebral angiography?
A. Transfemoral route
B. Transaxillary route
C. Direct carotid puncture
D. Transbrachial route
Correct answer : A. Transfemoral route
9. Which of the following ultrasound marker is associated with greatest increased risk for Trisomy 21 in fetus:
A. Echogenic foci in heart
B. Hyperechogenic bowel
C. Choroid plexus cysts
D. Nuchal edema
Correct answer : D. Nuchal edema
10. The most sensitive imaging modality for diagnosis of ureteric stones in a patient with acute colic is:
A. X-ray KUB region
C. Non contrast CT scan of the abdomen
D. Contrast enhanced CT scan of the abdomen
Correct answer : C. Non contrast CT scan of the abdomen
11. The gold standard for the diagnosis of osteoporosis is:
A. Dual energy X-ray absorptiometry
B. Single energy X-ray absorptiometry
D. Quantitative computed tomography
Correct answer : A. Dual energy X-ray absorptiometry
12. At t=0 there are 6 x 10^23 radioactive atoms of a substance, which decay with a disintegration constant equal to 0.01/sec. What would be the initial decay rate?
A. 6 X 10^23
a. 6 X 10^22
c. 6 X 10^21
d. 6 X 10^20
Correct answer : c. 6 X 10^21
Rate of decay = Disintegration constant X Number of radioactive atoms
= 0.01 X 6 x 10^23
= 6 X 10^21
13. The technique employed in radiotherapy to counteract the effect of tumour motion due to breathing is known as
A. Arc technique
Correct answer : C. Gating
Respiratory gating is a technique in radiotherapy in which the radiation is applied during that phase of respiratory cycle in which the tumour is in the best range. This is to prevent unnecessary radiation exposure to normal structures.
14. Which one of the following radioisotope is not used as permanent implant:
Correct answer : D. Caesium-137
Permanent implants for brachytherapy
15. In Radionuclide imaging the most useful radio pharamaceutical for skeletal imaging is:
A. Gallium 67
B. Technetium sulphur colloid
D. Technetium—99m linked to Methylene disphosphonate
Correct answer : D. Technetium—99m linked to Methylene disphosphonate
16. Gamma camera in Nuclear Medicine is used for:
A. Organ imaging
B. Measuring the radioactivity
C. Monitoring the surface contamination
Correct answer : B. Measuring the radioactivity
17. The MR imaging in multiple sclerosis will show lesions in:
A. White matter
B. Grey matter
D. Basal ganglia
Correct answer : A. White matter
Multiple sclerosis is a demyelinating disorder. Hence the lesions will be seen in the white matter (due to loss of myelin).
18. The most important sign of signficant renal artery stenosis in an angiogram is:
A. A percentage diameter stenosis > 70%
B. Presence of collaterals
C. A systolic pressure gradient > 20 mm Hg across the lesion
D. Poststenotic dilatation of the renal artery
Correct answer : B. Presence of collaterals
Presence of collaterals indicate that there is significant renal artery stenosis.
19. The most accurate investigation for assessing ventricular function is:
A. Multislice CT
C. Nuclear scan
Correct answer : B. Echocardiography
20. The procedure of choice for the evaluation of an aneurysm is:
B. Computed tomography
C. Magnetic resonance imaging
Correct answer : D. Arteriography
21. Which is the objective sign of identifying pulmonary plethora in a chest radiograph?
A. Diameter of the main pulmonary artery > 16 mm
B. Diameter of the left pulmonary artery > 16 mm
C. Diameter of the descending right pulmonary artery > 16 mm
D. Diameter of the descending left pulmonary artery > 16 mm
Correct answer : C. Diameter of the descending right pulmonary artery > 16 mm
22. Which of the following causes rib-notching in a chest radiograph?
A. Bidirectional Glenn shunt
B. Modified Blalock Taussig shunt
C. IVC occlusion
D. Coarctation of aorta
Correct answer : D. Coarctation of aorta
Causes of rib notching:
- Superior rib notching
- Restrictive lung disease
- Connective tissue disease
- Osteogenesis imperfecta
- Inferior rib notching
- Thrombosis of aorta
- Coarctation of arota
- Blalock Taussig shunt
- Occlusion of subclavian artery
- Pulmonary AV malformation
23. The ideal timing of radiotherapy for Wilms tumour after surgery is:
A. Within 10 days
B. Within 2 weeks
C. Within 3 weeks
D. Any time after surgery
Correct answer : A. Within 10 days
Radiotherapy is to be started within 10 days. Delay in starting radiotherapy for Wilm’s tumour can result in an increase in relapse rate.
24. Which one of the following imaging techniques gives maximum radiation exposure to the patient?
A. Chest X-ray
C. CT scan
Correct answer : C. CT scan
Typical effective dose (mSv) for various investigations:
Chest X-ray: 0.02
CT Head: 2.3
CT Chest: 8
CT Abdomen / Pelvis: 10
Bone scan (Tc-99m): 4
25. Phosphorus 32 emits:
A. Beta particles
B. Alpha Particles
D. X rays
Correct answer : A. Beta particles
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