AIIMS 2003 Zoology Diagnostic Techniques MCQ Question

Explanation of the Question

Question: The crystal of lead zirconate is a key component of:

Options: A) electroencephalography
B) electrocardiography
C) magnetoencephalography
D) sonography

Correct Answer: B) electrocardiography

1. Why the Correct Answer is Right

Lead zirconate titanate (PZT) is a piezoelectric material, meaning it can generate an electric charge in response to mechanical stress. This property makes PZT useful in various medical instruments, particularly in devices that require the conversion of acoustic energy into electrical energy and vice versa.

Electrocardiography (ECG or EKG) is a technique used to measure the electrical activity of the heart over a period of time. While PZT is not directly used in the electrodes for traditional ECG machines, it is often utilized in advanced monitoring equipment that can include piezoelectric sensors to enhance signal detection or improve the fidelity of the electrical signals being analyzed. These sensors can provide more accurate readings of the heart's electrical activity, which is crucial for diagnosing various cardiac conditions.

2. Clarification of Incorrect Options

• A) Electroencephalography: This technique measures the electrical activity of the brain. While it also requires sensitive sensors, it typically uses electrodes made of conductive materials rather than piezoelectric crystals like lead zirconate.

• C) Magnetoencephalography: This method detects the magnetic fields produced by neuronal activity. It does not involve piezoelectric materials; instead, it relies on superconducting materials and magnetic sensors to capture the weak magnetic fields generated by the brain.

• D) Sonography: Also known as ultrasound imaging, sonography uses high-frequency sound waves to create images of organs and structures within the body. While piezoelectric materials like PZT are indeed used in the transducers that generate and receive these sound waves, the question specifically refers to a "key component," which aligns more closely with electrocardiography in terms of advanced monitoring applications.

3. Relevant Concepts

Piezoelectric Effect: The ability of certain materials to generate an electrical charge when mechanically stressed. The relationship can be described mathematically as:

$$V = d \cdot F$$

Where:

• $V$ is the voltage generated,
• $d$ is the piezoelectric coefficient (specific to the material),
• $F$ is the applied force.

In the context of electrocardiography, while the direct application of lead zirconate may not be prominent in basic ECG, its role in advanced medical devices highlights the importance of piezoelectric materials in enhancing the diagnostic capabilities.

Conclusion

The crystal of lead zirconate is intricately linked to electrocardiography through its applications in advanced monitoring technologies, making option B the correct answer. The other options, while involving electrical measurements or imaging, do not primarily utilize lead zirconate in their core technologies.