# Range Equation Flashcards

What must travel to a reflector and return to the transducer to create a dot on the image?

A pulse of sound.

What is the term that describes the time it takes to go and return from the reflector?

Time of Flight

What is another way to think of the **Time of Flight**? (go and return)

Round trip.

What is the comparison between the trip to and from deeper structures vs the trip to and from superficial structures.

The time of flight is clearly **longer** for deeper structures.

What is the total distance a beam and echo travels ?

The **total distance** is from the source to the reflector and back, or the total **distance traveled** is twice the depth of the relfector.

What is the total time?

The time it takes for the beam to travel to the reflector and back. (round trip)

How do you calculate depth?

Rate x Time= Distance

How do you find the reflector depth?

(Rate x Time)/ **2** =DIstance

What is the ultrasound rate in soft tissues?

1.54mm/µsec

If a round trip to a soft tissue reflector snf back is **13µsec**, what is the reflector depth?

1.54 mm/µsec x 13µsec=10 mm →**1 cm**

A pulse of ultrasound is sent into the tissue. It stops to “hear” the echoes from the reflectors before it sends another pulse in. How long does it wait to send the next pulse in?

It depends on the **depth setting.** So when you set the depth, you set the timing of each pulse of ultrasound.

What is **PRP**?

**Pulse Repetition Period.**

It is the length of time to get between pulses (µsec)

What is the equation for **PRP?**

**PRP** (µsec)= image of death (cm) x 13 µsec/cm

What is the relationship between PRP and depth?

Directly proportional

What is **PRF**?

**Pulse Repetition Frequency**

**PRF** is the number of pulses sent per second (Hz)