Ch 5 Intensities

intensity is the US beam's ______ divided by its _____

power

area

- spatial

- peak

- average

- temporal

- pulsed

key words related to the intensities of pulsed waves

refers to distance or space

spatial

refers to all time, both transmit and receive

temporal

the maximum value of intensity

peak

the mathematical middle value of intensity

average

refers to only the transmit time

pulsed

transmit time, AKA

pulse duration

the beams intensity at the location where it's maximum

spatial peak intensity

the average intensity across the beams entire cross-section area

spatial average intensity

there are ___ different methods for measuring temporal intensity in pulsed US

4

the intensity of the beam at the instant in time of its maximal value

temporal peak intensity

the time-averaged intensity over the largest half cycle in the pulse at the spatial peak

maximum intensity

the average intensity during the pulse duration (during transmit time)

pulse average intensity

the average intensity during the entire PRP (both transmit and receive times)

temporal average intensity

largest value of temporal intensity

temporal peak intensity

smallest value of temporal intensity

temporal average intensity

1. temporal peak intensity

2. maximum intensity

3. pulse average intensity

4. temporal average intensity

temporal intensities from largest to smallest

temporal average intensity is _____ times lower than TPI because it includes listening time

500

measured at the location where intensity is maximum and the instant in time when the most powerful part of the pulse passes

spatial peak temporal peak

measured at the location where intensity is maximum, averaged over the transmit time only

spatial peak pulse average

measured at the location where intensity is maximum and averaged over all time, both transmit and receive times

spatial peak temporal average

measured over the entire cross sectional area of the sound beam, and over all time

spatial average temporal average

highest value of intensity measurements

Spatial peak temporal peak

**SPTP**

intensity measurement that is most important for thermal bioeffects

spatial peak, temporal average

**SPTA**

lowest value of intensity measurements

spatial average, temporal average

**SATA**

the ratio of the center intensity to the average spatial intensity; describes the spread of a beam in space

beam uniformity coefficient

beam uniformity coefficient, AKA

SP/SA Factor

for continuous wave US, the beam is always on, so the pulse average and temporal average will be ___________

the same

SPTA = SPPA

SATA = SAPA

when pulsed and continuous wave sound beams have the same peak intensity values (SPTP), the __________ wave intensity has the higher SPTA intensity value

continuous