Question

Consider the following statements: 
Assertion: Positron Emission Tomography (PET) uses radionuclides, such as 11C and 15N, to study tissue metabolism.
Reason: Positron-emitting nuclides are incorporated in molecules that are essential for metabolism.

• A. Both Assertion and Reason are true; Reason is not the correct explanation for the Assertion
• B. Both Assertion and Reason are true; Reason is the correct explanation for the Assertion
• C. Assertion is true, but Reason is false
• D. Both Assertion and Reason are false

Hint:

In PET scans, the incorporation of radionuclides into biologically active molecules allows the visualization of metabolic activity in tissues. This makes it particularly useful in cancer diagnosis and brain studies.

Answer 1

The Correct Option is B

Step 1: Understanding the Assertion
Positron Emission Tomography (PET) is a non-invasive imaging technique used to study tissue metabolism. It detects gamma rays resulting from positron-electron annihilation events. PET scanners typically use radionuclides like Carbon-11 (¹¹C) and Nitrogen-15 (¹⁵N), which are incorporated into biologically active molecules to trace metabolic processes in the body.

Step 2: Understanding the Reason
Positron-emitting nuclides are indeed incorporated into compounds that play a key role in metabolism—such as glucose, amino acids, and oxygen analogs. These radiolabeled compounds are taken up by active tissues, and PET imaging allows us to monitor their metabolic activity—especially useful in oncology, neurology, and cardiology.

Step 3: Conclusion
✅ Both the Assertion and the Reason are correct.
✅ The Reason accurately explains the Assertion.

✔️ Correct Answer: (B) — Both A and R are true, and R is the correct explanation of A.