Which of the following techniques uses strong magnetic fields and non-ionising radiations to detect pathological and physiological changes in living tissue?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → MRI
Several imaging methods help to detect cancers of the internal organs. They differ in what they use to form the image. Radiography and CT use X-rays, which are ionising radiations. MRI uses strong magnetic fields and non-ionising radiations.
Option (1) Radiography — Incorrect. Radiography is the use of X-rays to take pictures of internal organs. X-rays are ionising radiations and no magnetic field is used.
Option (2) CT scan — Incorrect. CT (computed tomography) also uses X-rays. It builds a three-dimensional image of the inside of the body, but it does not use magnetic fields.
Option (3) MRI — Correct. MRI (magnetic resonance imaging) uses strong magnetic fields and non-ionising radiations. It detects pathological and physiological changes in living tissue with accuracy.
Option (4) Biopsy — Incorrect. Biopsy is not an imaging method. A piece of the suspected tissue is cut into thin sections, stained and examined under a microscope by a pathologist.
NCERT Extract:
Cancer – “… In biopsy, a piece of the suspected tissue cut into thin sections is stained and examined under microscope (histopathological studies) by a pathologist. Techniques like radiography (use of X-rays), CT (computed tomography) and MRI (magnetic resonance imaging) are very useful to detect cancers of the internal organs. Computed tomography uses X-rays to generate a three-dimensional image of the internals of an object. MRI uses strong magnetic fields and non-ionising radiations to accurately detect pathological and physiological changes in the living tissue.”