What is the typical period range in microseconds for diagnostic ultrasound?

• A. 0.01 to 0.05 microseconds
• B. 0.1 to 0.5 microseconds
• C. 1 to 5 microseconds
• D. 5 to 50 microseconds

Answer: (B)

Period is the time for one cycle, and it’s the reciprocal of frequency (T = 1/f). Diagnostic ultrasound uses higher frequencies, roughly 2 to 15 MHz, because higher frequency beams provide better axial resolution for imaging. If you invert those frequencies, you get periods from about 0.067 microseconds at 15 MHz up to 0.5 microseconds at 2 MHz. In practice, that range is commonly summarized as about 0.1 to 0.5 microseconds. So the typical period falls within that window. The other ranges correspond to frequencies well outside the diagnostic ultrasound range, which is why they don’t fit.