How does an MRI produce an image?

When working with thermal infrared systems, if the targets in a scene have the same kinetic (i.e. physical) temperature will they also have the same brightness in the resulting image?

Ordinary X-ray photographs cannot produce sharp images of internal organs whose densities are not varying significantly from their surroundings. What technique overcomes this problem?

In relation to x-ray imaging, which of the following statements is true? Choose one answer.   a. The linear attenuation coefficient of a material is directly proportional to its half value thickness.     b. For clinically useful x-rays, lead has a greater half value thickness than soft tissue.     c. The intensity of an x-ray beam decreases exponentially as it passes through tissue.     d. The intensity of an x-ray beam increases exponentially as it passes through tissue.     e. Good contrast media are generally poor absorbers of X-rays.     and Why??