The sonographer can influence the duty factor of the ultrasound machine.

• A. True
• B. False
• C. Not applicable
• D. Only with hardware

Answer: (A)

Duty factor is the proportion of time the transducer is emitting ultrasound during each imaging cycle. It’s determined by how long each transmit pulse lasts (pulse duration) and how often pulses are sent (pulse repetition frequency, PRF). Since the sonographer can change both the number of cycles in a transmitted pulse and the imaging depth (which changes PRF), they can influence the duty factor. For example, using more cycles in a pulse lengthens the transmit time, increasing the duty factor, while increasing depth lowers PRF and can reduce the duty factor. Because these are user-controlled settings, the sonographer can indeed influence the duty factor.