The Verasonics [ultrasound] system with the Extended Transmit Option enables a s

ID: 2141606 • Letter: T

Question

The Verasonics [ultrasound] system with the Extended Transmit Option enables a series of "push"

sequences with the necessary pulse repetition frequency, pulse duration and acoustic power to displace

kidney stones in vitro and in vivo. By adjusting the control scripts and user interface software, a system

has been developed to facilitate clinical trials.

With the Extended Transmit Option an internal power supply with 48 Watt capacity is used. A large

energy storage capacitor provided within the system allows transmit for bursts with much higher energy

levels, provided that enough time is allowed between bursts to recharge the capacitor from the internal

supply. Approximately 20 Joules of energy is available from this capacitor (e.g. enough to provide 200

Watts output level for 0.1 second, or 2000 Watts for 10 milliseconds). Extended Burst Option is available

in configurations with either 128 or 256 transmit channels.

a. If the system were perfectly efficient, how long would it take the power supply to completely

charge the capacitor?

b. How long could the system provide 100 Watts?

c. How long do you think you could hold onto a 100 Watt lightbulb? (an old-fashioned,

inefficient incandescent).

i. 1 second?

ii. 1 hour?

iii. 1 day?

eenrgy/time = power

a. time = 20/48 = 0.416s

b. tiime = 20/100 =0.2s

c. it burst off in a sec

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