Figure 1.

Schematic diagram of three-dimensional ultrasound (US) mechanical scanning methods. (a) Side-firing transrectal US transducer being mechanically rotated. The acquired images have equal angular spacing. The same approach is used in a mechanically wobbled transducer. (b) A rotational scanning mechanism, typically used in three-dimensional US-guided prostate biopsy. The acquired images have equal angular spacing. (c) Linear mechanical scanning mechanism. The acquired images have equal spacing.