MCQs for radiographer exams, especially if you are preparing for an exam like the RRB (Railway Recruitment Board) Radiographer exam:
1. Which of the following is the most common type of X-ray interaction with matter in diagnostic radiography?
- a) Compton scattering
- b) Photoelectric effect
- c) Pair production
- d) Coherent scattering
Answer: a) Compton scattering
2. In a chest X-ray, which structure appears the most radiolucent?
- a) Bones
- b) Soft tissues
- c) Air
- d) Fat
Answer: c) Air
3. Which of the following is used to measure the radiation dose received by a patient?
- a) Geiger-Müller counter
- b) Dosimeter
- c) CT scanner
- d) MRI scanner
Answer: b) Dosimeter
4. The primary purpose of a grid in radiography is to:
- a) Reduce patient exposure
- b) Improve image contrast
- c) Increase image sharpness
- d) Reduce exposure time
Answer: b) Improve image contrast
5. The ALARA principle stands for:
- a) As Low As Reasonably Achievable
- b) As Little As Reasonably Allowed
- c) As Large As Reasonably Allowable
- d) As Long As Reasonably Achievable
Answer: a) As Low As Reasonably Achievable
6. Which of the following modalities uses non-ionizing radiation?
- a) X-ray
- b) CT
- c) MRI
- d) PET
Answer: c) MRI
7. The contrast agent most commonly used in MRI scans is:
- a) Iodine-based
- b) Barium sulfate
- c) Gadolinium
- d) Sodium chloride
Answer: c) Gadolinium
8. The anode in an X-ray tube is made of:
- a) Tungsten
- b) Aluminum
- c) Lead
- d) Copper
Answer: a) Tungsten
9. In fluoroscopy, the image intensifier is primarily used to:
- a) Protect the patient
- b) Enhance the brightness of the image
- c) Decrease radiation exposure
- d) Increase the scan speed
Answer: b) Enhance the brightness of the image
10. Which of the following is used to protect the thyroid from radiation exposure during imaging?
- a) Lead gloves
- b) Lead apron
- c) Thyroid collar
- d) Lead goggles
Answer: c) Thyroid collar
11. The characteristic radiation produced in an X-ray tube is primarily the result of:
- a) Bremsstrahlung interaction
- b) Electron excitation
- c) Outer-shell electron interaction
- d) Inner-shell electron interaction
Answer: d) Inner-shell electron interaction
12. Which of the following factors primarily controls the contrast of an X-ray image?
- a) mA (milliamperage)
- b) Exposure time
- c) kVp (kilovoltage peak)
- d) SID (source-to-image distance)
Answer: c) kVp (kilovoltage peak)
13. In computed tomography (CT), the Hounsfield unit (HU) of water is:
- a) 0
- b) 100
- c) -1000
- d) 1000
Answer: a) 0
14. Which type of radiation detector is commonly used in digital radiography?
- a) Photomultiplier tubes
- b) Scintillation detectors
- c) Photostimulable phosphor plates
- d) Thermoluminescent dosimeters
Answer: c) Photostimulable phosphor plates
15. The dose limit for occupational radiation exposure for radiologic personnel is:
- a) 5 mSv/year
- b) 20 mSv/year
- c) 50 mSv/year
- d) 100 mSv/year
Answer: c) 50 mSv/year
16. In mammography, the target material in the X-ray tube is typically:
- a) Tungsten
- b) Molybdenum
- c) Lead
- d) Copper
Answer: b) Molybdenum
17. The collimator in an X-ray machine is used to:
- a) Increase image resolution
- b) Focus the X-ray beam
- c) Reduce the patient's radiation exposure
- d) Magnify the image
Answer: c) Reduce the patient's radiation exposure
18. Which of the following imaging modalities uses positron-emitting radioisotopes?
- a) MRI
- b) PET
- c) Ultrasound
- d) CT
Answer: b) PET
19. Which factor is most responsible for patient dose in an X-ray exam?
- a) Exposure time
- b) Tube current (mA)
- c) Tube voltage (kVp)
- d) Source-to-image distance (SID)
Answer: b) Tube current (mA)
20. Which of the following conditions is necessary to produce an X-ray beam?
- a) High tube voltage and low tube current
- b) Electrons striking a target material
- c) Low tube voltage and high exposure time
- d) Electrons striking a cathode
Answer: b) Electrons striking a target material
21. The imaging technique that provides real-time, moving images of internal structures is called:
- a) Fluoroscopy
- b) MRI
- c) Ultrasound
- d) CT
Answer: a) Fluoroscopy
22. The total filtration in an X-ray beam includes which of the following?
- a) Glass envelope
- b) Collimator
- c) Inherent and added filtration
- d) Compression paddle
Answer: c) Inherent and added filtration
23. Which of the following is used to evaluate the uniformity of the X-ray field?
- a) Collimator alignment test
- b) Beam quality check
- c) Film-screen test
- d) Half-value layer test
Answer: a) Collimator alignment test
24. Which of the following radiation types has the greatest penetrating power?
- a) Alpha particles
- b) Beta particles
- c) Gamma rays
- d) Ultraviolet rays
Answer: c) Gamma rays
25. The term “pitch” in CT imaging refers to:
- a) The width of the X-ray beam
- b) The rotation speed of the gantry
- c) The ratio of table movement to slice thickness
- d) The number of detectors used
Answer: c) The ratio of table movement to slice thickness
26. In digital radiography, what does the term DICOM stand for?
- a) Digital Imaging and Communication in Medicine
- b) Direct Image Capture Over Media
- c) Digital Information and Computation Method
- d) Data Integration and Communication Module
Answer: a) Digital Imaging and Communication in Medicine
27. A "radiolucent" structure on an X-ray film appears:
- a) Black
- b) White
- c) Gray
- d) Bright
Answer: a) Black
28. Which of the following tissues is most radiosensitive?
- a) Muscle
- b) Bone
- c) Skin
- d) Lymphoid tissue
Answer: d) Lymphoid tissue
29. The primary function of the cathode in an X-ray tube is to:
- a) Absorb excess heat
- b) Accelerate electrons toward the anode
- c) Produce X-rays
- d) Control the exposure time
Answer: b) Accelerate electrons toward the anode
30. The unit of radiation exposure commonly used in the SI system is:**
- a) Sievert (Sv)
- b) Gray (Gy)
- c) Roentgen (R)
- d) Becquerel (Bq)
Answer: c) Roentgen (R)
31. A stochastic effect of radiation refers to:**
- a) A dose threshold below which no effect occurs
- b) An effect whose severity increases with dose
- c) A probabilistic effect that increases with dose
- d) A dose-dependent deterministic effect
Answer: c) A probabilistic effect that increases with dose
32. In radiography, which of the following would increase the size of the penumbra (blurring)?
- a) Decreasing the focal spot size
- b) Increasing the SID
- c) Increasing the object-to-image distance
- d) Decreasing the exposure time
Answer: c) Increasing the object-to-image distance
33. The primary advantage of using digital radiography over conventional film-screen radiography is:
- a) Reduced radiation exposure
- b) Faster image acquisition
- c) Improved contrast resolution
- d) All of the above
Answer: d) All of the above
34. Which of the following materials is most commonly used for the protective housing of an X-ray tube?
- a) Lead
- b) Aluminum
- c) Copper
- d) Steel
Answer: a) Lead
35. A focused grid is designed to:
- a) Remove scattered radiation
- b) Absorb primary radiation
- c) Increase magnification
- d) Reduce the exposure time
Answer: a) Remove scattered radiation
36. In MRI, T1-weighted images are primarily used to evaluate:
- a) Blood flow
- b) Soft tissue contrast
- c) Bone fractures
- d) Organ motion
Answer: b) Soft tissue contrast
37. In X-ray production, which of the following occurs when the electron beam strikes the anode?
- a) Photoelectric effect
- b) Pair production
- c) Thermionic emission
- d) Bremsstrahlung radiation
Answer: d) Bremsstrahlung radiation
38. Which of the following factors has the greatest effect on spatial resolution in digital radiography?
- a) kVp
- b) Focal spot size
- c) Exposure time
- d) Grid ratio
Answer: b) Focal spot size
39. In ultrasound imaging, the frequency of the sound waves used for diagnostic purposes typically ranges from:
- a) 2 to 20 MHz
- b) 2 to 20 kHz
- c) 20 to 40 MHz
- d) 0.5 to 2 MHz
Answer: a) 2 to 20 MHz
40. In a CT scan, increasing the pitch will:
- a) Improve image resolution
- b) Decrease the scan time
- c) Increase patient dose
- d) Reduce the field of view
Answer: b) Decrease the scan time
41. What is the effect of increasing the kVp in an X-ray exam?
- a) Increase patient dose
- b) Increase image contrast
- c) Reduce image contrast
- d) Reduce spatial resolution
Answer: c) Reduce image contrast
42. Which imaging modality uses the Doppler effect to assess blood flow?
- a) MRI
- b) CT
- c) Ultrasound
- d) Nuclear medicine
Answer: c) Ultrasound
43. Which of the following is used to protect a radiographer from scattered radiation?
- a) Gonadal shield
- b) Lead apron
- c) Lead gloves
- d) Thyroid collar
Answer: b) Lead apron
44. Which imaging technique is best suited for visualizing bone fractures?
- a) Ultrasound
- b) MRI
- c) X-ray
- d) CT
Answer: c) X-ray
45. What is the purpose of using contrast media in radiologic procedures?
- a) To reduce radiation exposure
- b) To enhance the visibility of soft tissues
- c) To reduce scan time
- d) To decrease image noise
**Answer:** b) To enhance the visibility of soft tissues
46. A dose of 1 Gray (Gy) is equivalent to:
- a) 1 rad
- b) 100 rem
- c) 100 rad
- d) 1000 rem
Answer: c) 100 rad
47. What type of radiation protection device is used for collimating the X-ray beam?
- a) Lead shield
- b) Filter
- c) Grid
- d) Aperture diaphragm
Answer: d) Aperture diaphragm
48. The biological effect of radiation depends on:
- a) Type of radiation
- b) Total dose received
- c) Rate of exposure
- d) All of the above
Answer: d) All of the above
49. A typical MRI scanner uses a magnetic field strength of:
- a) 0.5-1.0 Tesla
- b) 1.5-3.0 Tesla
- c) 4.0-5.0 Tesla
- d) 5.0-7.0 Tesla
Answer: b) 1.5-3.0 Tesla
50. Which of the following tissues has the lowest radiographic density and appears dark on an X-ray?
- a) Bones
- b) Muscle
- c) Air
- d) Fat
Answer: c) Air
51. The maximum permissible dose for a pregnant radiographer during the entire gestation period is:
- a) 0.5 mSv
- b) 5 mSv
- c) 10 mSv
- d) 50 mSv
Answer: b) 5 mSv
52. The principal source of radiation exposure to a radiographer during fluoroscopy is:
- a) Leakage radiation from the X-ray tube
- b) Scatter radiation from the patient
- c) Primary radiation beam
- d) Cosmic radiation
Answer: b) Scatter radiation from the patient
53. In digital radiography, pixel size is directly related to:
- a) Spatial resolution
- b) Image contrast
- c) Exposure time
- d) kVp
Answer: a) Spatial resolution
54. Which of the following is used to measure radiation exposure in radiography?
- a) Geiger counter
- b) Dosimeter
- c) Photodiode
- d) Spectrometer
Answer: b) Dosimeter
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