Question

Which of the following statements are CORRECT in the context of planar X-ray imaging?

• A. Using fast X-ray screen improves spatial resolution
• B. Using fast X-ray screen worsens spatial resolution
• C. Decreasing tube current decreases signal to noise ratio
• D. Decreasing tube current increases signal to noise ratio

Hint:

Fast X-ray screens are efficient but reduce image sharpness, and tube current directly affects the signal-to-noise ratio.

Answer 1

The Correct Option is B, C

In planar X-ray imaging, the use of different components (like the X-ray screen and tube current) significantly affects image quality.
1. Using fast X-ray screen improves spatial resolution: - This statement is incorrect. Using fast X-ray screens leads to lower spatial resolution because they require less exposure time, leading to a larger blur in the image. Fast screens are designed to reduce the exposure time, which can improve efficiency but reduces sharpness. Hence, (A) is incorrect.
2. Using fast X-ray screen worsens spatial resolution: - This statement is correct. As mentioned above, fast screens reduce spatial resolution due to the larger spread of the X-rays during the image capture process.
3. Decreasing tube current decreases signal to noise ratio: - This statement is correct. The tube current affects the amount of X-ray photons produced, which directly impacts the signal-to-noise ratio (SNR). Decreasing the tube current reduces the number of photons hitting the detector, thus decreasing the SNR.
4. Decreasing tube current increases signal to noise ratio: - This statement is incorrect, as explained above. A decrease in tube current leads to a decrease in the signal strength, thereby decreasing the SNR.
Thus, the correct answers are (B) and (C).