Cancer of internal organs can be detected by the following techniques…

The correct answer is Option (1) → (A), (B), (C) and (D)

Note: The given answer is as per the official NTA Answer Key. However, the answer according to NCERT would be Option (4), (A), (B) and (C) only, because autoradiography is not named as a technique for detecting cancer of the internal organs, as explained below.

Cancer of the internal organs is found by imaging the organs. The techniques named for this are radiography (X-rays), computed tomography and magnetic resonance imaging.

(A) X-rays — Correct. Radiography uses X-rays to show a growth in an internal organ.

(B) Computed tomography — Correct. It uses X-rays to make a three-dimensional image of the inside of an object.

(C) Magnetic resonance imaging — Correct. It uses strong magnetic fields and non-ionising radiation to detect pathological and physiological changes in living tissue.

(D) Autoradiography — Correct as per NTA; however, it is not named as an imaging technique for cancer of the internal organs. It is a laboratory technique in which a radioactive probe is made to show up on photographic film. It is used in DNA fingerprinting and in detecting mutated genes.

NCERT Extract:
Cancer – “… 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.”