Davies Publishing SPI Practice Test 2026 – Comprehensive Exam Prep

Grating lobes come from the interference pattern of an ultrasound array when the element spacing is regular and not small enough relative to the wavelength. When you steer the beam by applying delays across the elements, you tilt the main lobe, but if the transducer has spacing greater than about half a wavelength, additional maxima—grating lobes—emerge at specific off-axis angles. Steering actively changes the phase across the array, so it can reveal these secondary lobes, making beam steering the technique most likely to produce grating lobes.

Other imaging methods and processing steps don’t inherently create these off-axis maxima in the same way; tomographic or 3D imaging are about acquiring data from angles and reconstructing images, while speckle reduction imaging focuses on post-processing to reduce noise.