**Core Concept**
Piezoelectric crystals are materials that generate an electric charge in response to mechanical stress, such as pressure or vibration. This property is utilized in various medical applications, including ultrasonic imaging and lithotripsy.

**Why the Correct Answer is Right**
Ultrasonic imaging, specifically ultrasound, employs piezoelectric crystals to produce high-frequency sound waves that are directed into the body. When these sound waves encounter tissues, they are reflected back and detected by the same piezoelectric crystals, allowing for the creation of detailed images of internal structures. This technique relies on the principle of piezoelectricity to convert mechanical energy into electrical signals, which are then processed to produce diagnostic images.

**Why Each Wrong Option is Incorrect**
**Option A:** Ultraviolet (UV) spectroscopy uses ultraviolet light to analyze the absorption patterns of molecules, but it does not involve piezoelectric crystals.
**Option B:** Magnetic Resonance Imaging (MRI) utilizes a strong magnetic field and radio waves to generate detailed images of internal structures, but it does not rely on piezoelectric crystals.
**Option C:** X-ray computed tomography (CT) scans use X-rays to produce cross-sectional images of the body, but they do not employ piezoelectric crystals.

**Clinical Pearl / High-Yield Fact**
Piezoelectric crystals are also used in dental applications, such as orthodontic appliances and dental implants, where they help to detect and measure the forces applied to the teeth and surrounding tissues.

**Correct Answer:** C.