2007 General Studies, all questions

UPSC Prelims 2007 · General Studies

Question 123: Science and Technology

Which of the following types is used by computed tomography employed for visualization of the internal structure of human body?

aX-Ray
bSouth waves
cMagnetic resonance
dRadioisotopes

AnswerThe answer is (a).

Computed tomography (CT) uses X-rays: a rotating X-ray source and detectors record many cross-sectional views, and a computer combines them into images of slices of the body. Magnetic resonance imaging uses magnets and radio waves, not X-rays, and radioisotopes are used in nuclear imaging, not CT.

Why each option is right or wrong
  • (a) Correct: CT scanning uses X-rays.
  • (b) 'South waves' is not a medical imaging method; this looks like a typing error.
  • (c) Magnetic resonance is the basis of MRI, not CT.
  • (d) Radioisotopes are used in PET and nuclear scans, not CT.

Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2007, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.