____ are a summation of side lobes generated by array transducers.

• A. Side lobes
• B. Acoustic speckle
• C. Grating lobes
• D. Reverberation

Answer: (C)

Grating lobes arise as a summation of side lobes generated by array transducers. When multiple elements form an array, their emitted waves interfere across angles, creating a diffraction-like pattern. If the spacing between elements is too large relative to the wavelength, this interference produces additional maxima outside the main beam—the grating lobes. These lobes carry energy in directions other than the intended focus and can generate false echoes or degrade image quality. To minimize them, keep inter-element spacing at about half a wavelength or less and use apodization to reduce side-lobe strength. For contrast, side lobes are simply secondary maxima within the main beam of a single element, acoustic speckle comes from the constructive and destructive interference of tissue scatterers, and reverberation is multiple reflections between interfaces creating echoes.