Which statement is true about spectral-domain OCT compared to time-domain?

Which statement is true about spectral-domain OCT compared to time-domain?

• A. It Offers Faster Scanning Speeds Due to a Stationary Reference Mirror.
• B. It Uses a Moving Reference Mirror and Slower Speeds.
• C. It Has Lower Sensitivity Than Time-Domain.
• D. It Cannot Image Deeper Structures.

Answer: (A)

In spectral-domain OCT, the reference mirror is stationary and depth information is extracted from the interference spectrum. The system measures the entire spectrum at once and uses a Fourier transform to reconstruct the depth profile, so you get an A-scan without moving the reference arm. Because there’s no mechanical sweep of the reference mirror, scanning can be much faster than in time-domain OCT. Spectral-domain also typically offers higher sensitivity and better depth performance than time-domain, since all backscattered light is used more efficiently. The other statements describe time-domain features (moving reference mirror and slower speeds) or claim lower sensitivity or limited depth, which don’t apply to spectral-domain.

In spectral-domain OCT, the reference mirror is stationary and depth information is extracted from the interference spectrum. The system measures the entire spectrum at once and uses a Fourier transform to reconstruct the depth profile, so you get an A-scan without moving the reference arm. Because there’s no mechanical sweep of the reference mirror, scanning can be much faster than in time-domain OCT. Spectral-domain also typically offers higher sensitivity and better depth performance than time-domain, since all backscattered light is used more efficiently. The other statements describe time-domain features (moving reference mirror and slower speeds) or claim lower sensitivity or limited depth, which don’t apply to spectral-domain.