Chapter 4 - p.91

Question 1

In bone, what is the roundtrip acoustic transit time to a target 2.04 cm deep ?

Answer 1

10 micro sec

Question 2

How far can ultrasound travel through soft tissue in

a. 1 second ?
b. 2 second ?
c. 10 second ?

Answer 2

a. 1540 m
b. 3080 m
c. 15.4 km

Question 3

To what depth can ultrasound travel through air (presuming roundtrip flight) in :
1 second ?
2 second ?
10 seconds ?

Answer 3

a. 165.5 m
b. 331 m
c. 1655 m

Question 4

What is the minimum PRP and maximum PRF to image in soft tissue at a depth of 5 cm ?

Answer 4

PRF = 15 kHz

Question 5

What is the maximum frame rate if it takes 0.1 msec to transmit a single line with 100 lines per frame ?

Answer 5

100 HZ or 100 frame / sec

Question 6

For color doppler , the same line is transmitted multiple times to improve signal to noise . A packet is defined as the number of times a specific line is transmitted. At a depth of 10 cm in soft tissue , with a packet size of 10 and 100 packets per frame , what is the maximum frame rate ?

Answer 6

frame rate = 7 Hz

frame time = 0.13 sec/frame

Question 7

If a pulse contains 8 cycles and the period is 0.2 microsec. what is the pulse duration ?

Answer 7

1.6 microsec

Question 8

If a pulse contains 8 cycles and the frequency is 1 mhz . What is the pulse duration ?

Answer 8

8 microsec

Question 9

If PD is 10 msec and the frequency is 1 kHz , how many cycles are in the pulse ?

Answer 9

10 cycles

Question 10

If system A has 4 cycles/pulse and and is operating at 5MHz and system B has 4 cycles/pulse and is operating at 10 Mhz , which system has a shorter pulse duration?

Answer 10

System B has a shorter pulse duration

Question 11

If 2 systems are operating at the same frequency and the same number of cycles per pulse , then the pulse duration

a) are equal
b) are unequal
c) cannot be determined

Answer 11

a.

If 2 systems are operating at the same frequency , then the periods are equal. Since both pulses have the same number of cycles , the P.D must be equal

Question 12

If the PD = 2 msec and the PRP = 5 msec, what is the duty cycle ?

Answer 12

40 %

Question 13

If the duty cycle is 0.6 % and the PRP is 10msec, what is the PD?

Answer 13

0.06 msec

Question 14

If the duty cycle is 0.6 % and the PRF is 0.1 khz , what is the PD ?

Answer 14

PD = 0.06 msec

Question 15

A duty factor of 100% has a special name , what is it?

Answer 15

transmit is continuous

hence continuous wave