Which camera is used in SPECT imaging?

• A. X-ray camera
• B. Optical camera
• C. Gamma camera
• D. Ultrasound probe

Answer: (C)

SPECT imaging relies on detecting gamma rays emitted by a radioactive tracer inside the body. The camera used for this purpose is the gamma camera, which is designed to detect single gamma photons. It uses a scintillation crystal (typically NaI(Tl)) that converts incoming gamma photons into light, with photomultiplier tubes translating that light into electrical signals. A collimator provides directional information, and by rotating around the patient, the system gathers data from multiple angles to reconstruct cross-sectional images of tracer distribution. X-ray cameras detect transmitted X-rays, optical cameras detect visible light, and ultrasound probes use sound waves, so they aren’t suited for capturing the gamma photons produced in SPECT.