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Question 1. Which subatomic particle determines the atomic number of an element? A) Neutron B) Electron C) Proton D) Positron Answer: C Explanation: The number of protons in the nucleus defines the atomic number, which uniquely identifies an element. Question 2. In X‑ray production, what is the primary mechanism that creates bremsstrahlung radiation? A) Electron capture by the nucleus B) Deceleration of electrons in the target material C) Transition of electrons between inner shells D) Radioactive decay of the anode material Answer: B Explanation: Bremsstrahlung (“braking radiation”) occurs when high‑energy electrons are abruptly slowed by the electric field of the target atoms, emitting a continuous spectrum of X‑rays. Question 3. Which component of the X‑ray tube focuses the electron stream onto a small area of the anode? A) Filament B) Focusing cup C) Glass envelope D) Tube housing Answer: B Explanation: The focusing cup, a negatively charged electrode surrounding the filament, directs electrons toward a precise spot on the anode, defining the focal spot size.
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Question 4. What is the effect of increasing the kilovoltage peak (kVp) on the contrast of a radiographic image? A) Increases contrast B) Decreases contrast C) No effect on contrast D) Increases noise only Answer: B Explanation: Higher kVp produces higher‑energy photons that penetrate tissues more uniformly, reducing the difference in attenuation between structures and thus lowering contrast. Question 5. Which type of generator provides a continuous high‑frequency alternating current to the X‑ray tube? A) Single‑phase rectifier B) Three‑phase rectifier C) High‑frequency generator D) Low‑frequency transformer Answer: C Explanation: High‑frequency generators produce a stable, high‑frequency AC that is rectified to supply the tube, allowing shorter exposure times and less heat buildup. Question 6. The law of Bergonie and Tribondeau states that cells are more radiosensitive when they: A) Have a large diameter and low mitotic rate B) Are highly differentiated and quiescent C) Have a high mitotic activity and low differentiation D) Contain high concentrations of calcium Answer: C Explanation: Radiosensitivity is greatest in cells that divide rapidly and are poorly differentiated, because DNA damage is less likely to be repaired before division.
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Question 10. The inverse square law states that radiation intensity is inversely proportional to the square of the distance from the source. If the distance is doubled, the intensity becomes: A) One‑quarter B) One‑half C) Double D) Unchanged Answer: A Explanation: Doubling the distance squares the denominator (2² = 4), so intensity decreases to 1/4 of the original value. Question 11. Which of the following is a deterministic (short‑term) effect of radiation exposure? A) Leukemia B; Carcinoma formation C) Skin erythema D; Genetic mutation Answer: C Explanation: Deterministic effects have a threshold dose; skin erythema appears after a certain dose and severity increases with dose. Question 12. What is the primary purpose of adding aluminum filtration to an X‑ray beam? A) Increase patient dose B) Remove low‑energy photons that contribute to skin dose C) Decrease beam hardness D) Enhance image contrast Answer: B Explanation: Added filtration absorbs low‑energy photons that would be absorbed in the patient’s skin, thereby “hardening” the beam and reducing unnecessary dose.
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Question 13. In the context of patient identification, which combination satisfies the two‑identifier rule? A) Name only B) Date of birth only C) Name and medical record number D) Room number only Answer: C Explanation: Using two independent identifiers, such as name and medical record number, reduces the risk of misidentification. Question 14. Which of the following best describes a rotating anode’s advantage over a stationary anode? A) Produces lower heat per unit exposure B) Generates higher kVp values C) Allows larger focal spots without overheating D) Reduces the need for filtration Answer: C Explanation: The rotating anode spreads the heat over a larger surface area, permitting larger focal spots and higher mA without damaging the tube. Question 15. A patient requires a PA chest radiograph. Which of the following is the correct positioning of the central ray (CR)? A) 10 cm above the clavicle, centered on the spine B) 10 cm below the clavicle, centered on the spine C) At the level of the nipple, 1 cm lateral to the spine D) At the level of the sternum, 2 cm lateral to the spine Answer: B Explanation: For a PA chest, the CR is aimed 10 cm below the clavicles, centered on the vertebral column to include the entire lung fields.
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Question 19. Which of the following is a common artifact caused by a metal object placed on a CR plate? A) Motion blur B) Grid cutoff C) Ghosting D) Streak artifact Answer: D Explanation: Dense metal objects cause X‑ray attenuation that appears as bright streaks on the image, known as streak artifacts. Question 20. The “10‑day rule” for a pregnant patient refers to: A) Performing a pregnancy test 10 days before any radiologic procedure B) Waiting 10 days after a radiologic exam before confirming pregnancy status C) Performing a pregnancy test within 10 days prior to a radiologic exam that may expose the fetus D) Limiting fetal dose to 10 mGy over 10 days Answer: C Explanation: The rule requires a pregnancy test be performed within 10 days before any potentially harmful radiologic procedure to ensure the patient’s status is current. Question 21. Which of the following best describes the effect of increasing the object‑to‑image distance (OID) on magnification? A) Magnification decreases B) Magnification increases C) No change in magnification D) Image becomes inverted Answer: B Explanation: Magnification is proportional to OID; as the object moves farther from the detector, the image size enlarges.
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Question 22. Which of the following is NOT a component of the three cardinal principles of radiation protection for personnel? A) Time B) Distance C) Shielding D) Frequency Answer: D Explanation: The three principles are minimizing exposure time, maximizing distance, and using appropriate shielding. Frequency is not a cardinal principle. Question 23. In a lateral cervical spine radiograph, which anatomical structure should be centered at the level of the C4 vertebral body? A) The odontoid process B) The hyoid bone C) The spinous processes of C4‑C D) The clavicles Answer: C Explanation: Proper centering for a lateral cervical view places the spinous processes of C4‑C5 at the detector’s center to include the full cervical column. Question 24. Which of the following best defines “grid ratio” in an X‑ray grid? A) The number of lead strips per inch B) The height of the lead strips divided by the distance between them C) The thickness of the grid material D) The degree of grid movement during exposure Answer: B Explanation: Grid ratio is the ratio of the height of the lead strips to the interspace width; higher ratios provide more scatter removal but increase dose.
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Question 28. Which of the following best describes the effect of a high‑frequency generator on tube heat? A) Increases heat because of longer exposure time B) Decreases heat because of shorter exposure time C) Has no effect on heat generation D) Causes the anode to melt faster Answer: B Explanation: High‑frequency generators allow very short exposure times, reducing the total heat generated in the anode per exposure. Question 29. The term “scatter” in radiography primarily refers to: A) Primary photons that have not interacted with the patient B) Photons that have changed direction after interacting with matter C) Electrons emitted from the cathode D) Noise generated by the detector electronics Answer: B Explanation: Scatter photons are those that have undergone Compton or Rayleigh interactions within the patient, altering their trajectory and degrading image quality. Question 30. Which of the following is the most appropriate method to reduce patient dose when imaging a large adult abdomen? A) Decrease kVp and increase mAs B) Increase kVp and decrease mAs C) Use a smaller focal spot size D) Increase the SID to 125 cm without adjusting other factors Answer: B Explanation: Raising kVp produces a more penetrating beam, allowing a reduction in mAs, which lowers the total number of photons and therefore patient dose while maintaining image density.
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Question 31. In spine imaging, the “clavicle” is used as a reference point for which view? A) Lateral lumbar spine B) AP pelvis C) PA chest D) None; clavicle is not used in spine positioning Answer: D Explanation: The clavicle is not a reference point for spinal views; it is used in chest imaging. Question 32. Which of the following personal monitoring devices provides the most accurate dose measurement for low‑level occupational exposure? A) Film badge B) Thermoluminescent dosimeter (TLD) C) Pocket ionization chamber D) Lead apron with built‑in sensor Answer: B Explanation: TLDs are highly sensitive and can accurately record low doses over time, making them preferred for routine occupational monitoring. Question 33. Which of the following best describes “magnification” on a radiograph? A) Increase in image contrast due to higher kVp B) Enlargement of the object’s image relative to its true size C) Reduction of scattered radiation D) Improvement in spatial resolution Answer: B Explanation: Magnification is the geometric enlargement of the object’s image on the detector, determined by the ratios of SID and OID. Question 34. In a PA chest radiograph, which anatomical marker should be placed on the patient’s right side?
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B) Decreased intensity on the anode side of the beam C) Uniform beam intensity across the field D) Increased heat on the anode’s peripheral edge Answer: B Explanation: The heel effect causes the intensity to be lower on the anode side due to the geometry of the target, resulting in a gradient of exposure across the field. Question 38. Which of the following is the most appropriate action when a patient shows signs of an allergic reaction to contrast media during a radiographic exam? A) Continue the exam and document the reaction later. B) Immediately stop the procedure and notify the physician. C) Increase the contrast dose to overcome the reaction. D) Apply a lead apron to the patient. Answer: B Explanation: Patient safety is paramount; the procedure must be halted, and medical assistance should be obtained promptly. Question 39. In a lateral knee radiograph, the central ray should be directed at which anatomical landmark? A) Mid‑patella B) Tibial tuberosity C) Fibular head D) Medial femoral condyle Answer: A Explanation: The central ray is aimed at the midpoint of the patella to ensure inclusion of the entire knee joint. Question 40. Which of the following statements about the relationship between SID and image sharpness is correct? A) Increasing SID always decreases image sharpness.
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B) Increasing SID reduces geometric unsharpness, improving sharpness. C) SID has no effect on image sharpness. D) Decreasing SID improves sharpness by reducing magnification. Answer: B Explanation: A larger source‑to‑image distance reduces the penumbra (geometric unsharpness), resulting in a sharper image. Question 41. The purpose of a “lead shield” placed behind the patient’s abdomen during a pelvic X‑ray is to: A) Increase image contrast of the pelvis B) Reduce scatter reaching the detector from the abdomen C) Protect the patient’s gonads from primary beam exposure D) Prevent the anode from overheating Answer: B Explanation: A posterior lead shield absorbs scattered photons emerging from the abdomen, decreasing scatter on the detector and improving image quality. Question 42. Which of the following best describes the purpose of a “full‑wave rectifier” in an X‑ray unit? A) Convert AC to DC, delivering both halves of the waveform to the tube B) Convert only the positive half‑cycle of AC to DC C) Increase the kVp output of the generator D) Reduce the filament current Answer: A Explanation: A full‑wave rectifier allows both the positive and negative halves of the AC waveform to be used, providing a smoother, higher‑current DC output to the tube. Question 43. Which of the following is a common cause of “grid cutoff” in a portable X‑ray unit? A) Using a grid with a low ratio
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C) They are emitted when inner‑shell electrons are replaced. D) They appear as sharp peaks on an X‑ray spectrum. Answer: B Explanation: Characteristic X‑rays have discrete energies, not a continuous spectrum; the continuous part belongs to bremsstrahlung. Question 47. The primary purpose of a “lead apron” worn by the technologist during portable radiography is to: A) Increase the exposure of the patient B) Reduce scattered radiation reaching the technologist C) Improve image contrast D) Keep the equipment clean Answer: B Explanation: Lead aprons protect the technologist from scattered radiation, especially when working close to the patient. Question 48. In a PA chest radiograph, what is the recommended source‑to‑image distance (SID)? A) 60 cm B) 80 cm C) 100 cm D) 120 cm Answer: C Explanation: Standard PA chest imaging uses a SID of 100 cm (40 in) to achieve appropriate magnification and image quality. Question 49. Which of the following best defines “spatial resolution” in radiography? A) Ability to distinguish differences in density B) Ability to differentiate small structures that are close together C) Amount of radiation absorbed by the patient
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D) Speed at which the image is acquired Answer: B Explanation: Spatial resolution refers to the capability of an imaging system to depict fine detail, i.e., to separate two points that are close together. Question 50. Which of the following is the most appropriate response if a patient reports a metallic implant before a lumbar spine X‑ray? A) Proceed without any changes. B) Increase kVp to penetrate the metal. C) Remove the implant before imaging. D) Use a higher mAs to improve image quality. Answer: B Explanation: Increasing kVp produces higher‑energy photons that can better penetrate metal, reducing artifact while maintaining dose considerations. Question 51. Which of the following best describes the function of a “collimator” on an X‑ray tube? A) Increases beam intensity B) Narrows the X‑ray beam to the area of interest, reducing scatter and dose C) Adjusts the kVp automatically D) Rotates the anode during exposure Answer: B Explanation: Collimation limits the size and shape of the X‑ray field, decreasing scatter radiation and patient dose while improving image quality. Question 52. In digital radiography, what does the term “ghosting” refer to? A) Persistent image from a previous exposure on the detector B) Motion blur caused by patient movement C) Artifact from metallic objects D) Overexposure of the image
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Answer: B Explanation: Centering at the midpoint of the metacarpals ensures inclusion of all carpal and digital structures. Question 56. Which of the following best explains why a higher grid ratio improves image contrast? A) It increases the number of primary photons reaching the detector. B) It removes more scattered photons relative to primary photons. C) It reduces the need for filtration. D) It shortens the exposure time. Answer: B Explanation: A higher grid ratio has taller lead strips, which absorb more scatter while allowing primary photons to pass, thereby increasing contrast. Question 57. Which of the following is considered a stochastic effect of ionizing radiation? A) Skin erythema B) Cataract formation C) Leukemia D) Hair loss Answer: C Explanation: Stochastic effects, such as leukemia, have no threshold and the probability increases with dose; severity is independent of dose. Question 58. During a portable chest X‑ray, the technologist must place the image receptor at: A) 100 cm from the patient’s chest B) 180 cm from the X‑ray tube focal spot C) Directly under the patient’s back, as close as possible to the chest D) 40 cm above the patient’s shoulders Answer: C
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Explanation: For portable imaging, the receptor is placed directly under the patient to minimize OID and improve image quality. Question 59. Which of the following is the correct order of steps for verifying patient identity according to the two‑identifier rule? A) Ask name → ask date of birth → check wristband → proceed B) Check chart → ask name → ask medical record number → confirm with patient C) Verify insurance → ask name → ask address → obtain consent D) Ask for name only → compare with electronic record → start exam Answer: B Explanation: The proper procedure involves checking the chart, asking for two independent identifiers (e.g., name and medical record number), and confirming with the patient before proceeding. Question 60. In a PA pelvis radiograph, the central ray is directed at which anatomical landmark? A) The symphysis pubis B) The sacroiliac joint C) The midpoint of the femoral heads D) The greater trochanter Answer: C Explanation: Centering at the midpoint of the femoral heads ensures both hips are adequately visualized and the pelvis is properly positioned. Question 61. Which of the following best describes the function of a “lead shield” placed under the patient’s abdomen during a pelvic X‑ray? A) Increase the exposure of the pelvic bones B) Reduce scatter reaching the detector from the abdomen C) Protect the patient’s reproductive organs from primary beam D) Harden the X‑ray beam Answer: B
