**Core Concept**
Gamma rays are a type of ionizing radiation used in various medical imaging modalities. In the context of bone imaging, gamma rays are employed to detect and visualize areas of increased bone metabolism, which can be indicative of certain pathologies.

**Why the Correct Answer is Right**
Gamma rays are used in bone scintigraphy, a type of nuclear medicine imaging. In this modality, a radiopharmaceutical containing a gamma-emitting isotope, such as technetium-99m (Tc-99m) or gallium-67 (Ga-67), is administered to the patient. The radiopharmaceutical accumulates in areas of increased bone metabolism, emitting gamma rays that can be detected by a gamma camera. The resulting images provide valuable information about bone structure and function.

**Why Each Wrong Option is Incorrect**
**Option A:** Fluoroscopy uses X-rays to produce real-time images of internal structures, but it does not involve the use of gamma rays.
**Option B:** CT scans use X-rays, not gamma rays, to produce cross-sectional images of the body.
**Option C:** MRI uses magnetic fields and radio waves to produce detailed images of internal structures, without the use of ionizing radiation like gamma rays.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that gamma rays are used in nuclear medicine imaging, particularly in bone scintigraphy, to detect and visualize areas of increased bone metabolism. This is a critical application of gamma rays in medical imaging.

✓ Correct Answer: D. Bone scan