Pulsed Sound Flashcards
What is a collection of cycles that travel together?
Pulse
What type of pulses are used to create anatomic images in diagnostic imaging?
Short pulses of acoustic energy
What are the two components of pulsed ultrasound?
“On” or “transmit” time, and the “dead”, “off”, or “receive” time
What are the parameters of pulsed sound?
Pulse duration, pulse repetition period, PRF, Duty Factor, spatial pulse length
The time from the start of a pulse to the end of that pulse
Pulse duration
In what units is pulse duration measured?
Microseconds, or any unit of time
What is the equation for pulse duration?
Pulse duration = # of cycles in pulse x period
In clinical imaging, how many cycles is a pulse comprised of?
2–4 cycles
Can the pulse duration be changed by the sonographer?
No, pulse duration is a characteristic of each transducer. It does not change when sonographer alters imaging depth. Remember, a pulse is a pulse is a pulse. A transducer’s talking time does not change.
The length or distance that an entire pulse occupies in space
Spatial pulse length
In what units is spatial pulse length measured?
Millimeters, or any unit of distance
Can spatial pulse length be changed by the sonographer?
No
What is the equation for spatial pulse length?
Spatial pulse length (mm) = # of cycles x wavelength (mm)
Which creates higher-quality images, short pulses or long pulses?
Shorter pulses create higher-quality images because spatial pulse length determines axial resolution, which affects image quality.
What is the time from the start of one pulse to the start of the next pulse? It includes one pulse duration and one listening time.
Pulse repetition period