PTAP 1240 – ULTRASOUND TEST NEW
UPDATED
ultrasound - ANSWER -sound waves with a frequency greater than 20,000
hertz
-has a thermal/nonthermal effect when applied to the body
sound waves enter the body and are attenuated by? - ANSWER -absorption
-reflection
-refraction
attenuation - ANSWER: gradual decrease in intensity as ultrasound travels
through tissue
absorption - ANSWER -some tissues are capable of greater absorption of
ultrasound than others
-tissue and frequency specific
-higher absorption occurs in tissue with a high collagen rate and with higher us
frequencies
ultrasound energy absorption - ANSWER best in tendon, ligament, fascia joint
capsule and scar tissue
reflection of a sound wave - ANSWER occurs when the wave passes between
two tissues and a fraction of the wave "bounces" back
refraction - ANSWER occurs when the US signal is deflected from a straight
path and the angle of deflection is away from the transducer
coupling agents - ANSWER gel and water
US parameters - ANSWER -effective radiating area (ERA) -cm2
-beam nonuniformity ratio (BNR)- ratio
, -intensity- w.cm2
-frequency- MHZ
-duty cycle-%
effective radiating area (ERA) - ANSWER -area of the crystal that actually
produces sound waves
-energy is concentrated near the center
-era is always smaller than the total size of the transducer head
beam profile - ANSWER -multiple ways to emerge from the head
-energy diverges as it moves away from the source
-energy is uniform close to the head (fresnel zone)
-becomes less consistent farther away from the head (spatial peak intensity)
beam nonuniformity ration (BNR) - ANSWER -describes amount of variation
in the beam
-perfect beam would have a BNR of 1:1
ration is between the spatial peak intensity and spatial averaged intensity
-high the quality of the crystal, the lower the BMR
-lower BNR is more favorable since patients will be less likely to experience
hot spots and discomfort during treatment
frequency - ANSWER -selected according to the depth of the tissue to be
treated
-US delivered at a higher frequency is absorbed more rapidly than US delivered
at a lower frequency
3 MHZ - ANSWER reaches soft tissues 1-2 cm deep
1 MHZ - ANSWER reaches soft tissues up to 5 cm deep
intensity - ANSWER -measures the quantity of energy delivered per unit area
-spatial average intensity: the average intensity of the US input over the area of
the transducer; expressed in w/cm2
-selected according to treatment goal
-3 MHZ increases tissue temp ~3x faster than 1 MHZ when same
UPDATED
ultrasound - ANSWER -sound waves with a frequency greater than 20,000
hertz
-has a thermal/nonthermal effect when applied to the body
sound waves enter the body and are attenuated by? - ANSWER -absorption
-reflection
-refraction
attenuation - ANSWER: gradual decrease in intensity as ultrasound travels
through tissue
absorption - ANSWER -some tissues are capable of greater absorption of
ultrasound than others
-tissue and frequency specific
-higher absorption occurs in tissue with a high collagen rate and with higher us
frequencies
ultrasound energy absorption - ANSWER best in tendon, ligament, fascia joint
capsule and scar tissue
reflection of a sound wave - ANSWER occurs when the wave passes between
two tissues and a fraction of the wave "bounces" back
refraction - ANSWER occurs when the US signal is deflected from a straight
path and the angle of deflection is away from the transducer
coupling agents - ANSWER gel and water
US parameters - ANSWER -effective radiating area (ERA) -cm2
-beam nonuniformity ratio (BNR)- ratio
, -intensity- w.cm2
-frequency- MHZ
-duty cycle-%
effective radiating area (ERA) - ANSWER -area of the crystal that actually
produces sound waves
-energy is concentrated near the center
-era is always smaller than the total size of the transducer head
beam profile - ANSWER -multiple ways to emerge from the head
-energy diverges as it moves away from the source
-energy is uniform close to the head (fresnel zone)
-becomes less consistent farther away from the head (spatial peak intensity)
beam nonuniformity ration (BNR) - ANSWER -describes amount of variation
in the beam
-perfect beam would have a BNR of 1:1
ration is between the spatial peak intensity and spatial averaged intensity
-high the quality of the crystal, the lower the BMR
-lower BNR is more favorable since patients will be less likely to experience
hot spots and discomfort during treatment
frequency - ANSWER -selected according to the depth of the tissue to be
treated
-US delivered at a higher frequency is absorbed more rapidly than US delivered
at a lower frequency
3 MHZ - ANSWER reaches soft tissues 1-2 cm deep
1 MHZ - ANSWER reaches soft tissues up to 5 cm deep
intensity - ANSWER -measures the quantity of energy delivered per unit area
-spatial average intensity: the average intensity of the US input over the area of
the transducer; expressed in w/cm2
-selected according to treatment goal
-3 MHZ increases tissue temp ~3x faster than 1 MHZ when same
