Definitions
Beam Power divided by area
Intensity
Measured at the location where intensity is max and at the instant when the most powerful part of the pulse passes.
Isptp
What are the units for Intensity
watts/cm^2
Intensity ,ay be reported in various ways in respect to
Time and space
What describes the relationship of the beam intensities with time?
Duty Factor (also unitless)
When an ultrasound beam does not have the same intensity at different locations it is referring to which type of Intensity?
Spatial
Measured at the location where intensity is max, averaged over the transmit time (pulse duration)
Isppa
Measuring intensity of the beam at the instant in time of its max value
Temporal peak intensity (Itp
Different measurements of intensities are important in the study of
Bioeffects
What type of ultrasound wave has a beam that is always "on" and has a pulse average and temporal average intensities that are equal?
Continuous Wave
The max value is which type of intensity.
Peak
Measured at the location where intensity is max and average over all time, both the transmit and receive time.
Ispta
Determining the average intensity during the most intense half cycle
Imax or Im
Because peak measurements are larger than average measurements ______ intensity has the highest value
SPTP
Spatial Peak, Temporal Peak
When Pulsed and continuous wave beams have the same ____ intensities, the continuous wave beam has the higher SPTA intensity.
SPTP (spatial peak, temporal peak)
What type of Intensity refers to the fact that a pulsed beam does not have the same intensity at all times.
Temporal
Measured over the entire cross sectional area of the sound beam, and over all time.
Isata
Taking the average intensity during the pulse duration
pulse average intensity (Ipa)
Beacuse peak measurements are larger than average meaurements, _____ has the lowest value
SATA
Spatial Average, Temporal Average
What is the rank of intensities from largest to smallest?
SPTP, Im, SPPA, SPTA, SATA
What type of intensity refers to the middle value
Average
What is the most relevant intensity with respect to tissue heating?
SPTA
averaging the intensity during the entire repetition period
Temporal average intensity (Ita)
What are the units of Beam uniformity coefficient (SP/SA)?
It is unitless with a value of 1 or greater
What are the Temporal intensities from larges to smallest?
Itp, Imax, Ipa, Ita