Davies SPI 153 questions with complete solutions

Interference patterns of reflected waves causes? CORRECT ANSWERS: acoustic speckle which of the following terms denotes the time it takes for one cycle to occur? CORRECT ANSWERS: Period which of the following increases as frequency increases? CORRECT ANSWERS: absorption scattering attenuation What is meant by the dead zone in performance testing? CORRECT ANSWERS: Distance from the transducer to the first identifiable echo. What sound-tissue interaction is necessary to form an ultrasound image? CORRECT ANSWERS: Reflection According to Snell's law, the angle of transmission is related to the incident beam angle and; CORRECT ANSWERS: The relative speeds of sound in the two media. Which tissue has the highest rate of attenuation of an ultrasound wave? CORRECT ANSWERS: lung When you image sound reflected from a large, smooth interface, you are observing results of: CORRECT ANSWERS: specular reflection Attenuation of the sound beam increases with increasing; CORRECT ANSWERS: path length absorption frequency scattering reflection If the number of cycles in a pulse is increased but the wavelength remains the same, which of the following is true? CORRECT ANSWERS: the pulse duration is increased The thermal index indicates. CORRECT ANSWERS: Estimated temperature increase in tissue you are performing a sonogram and notice that the thermal index (TI) is greater than 1. Any increase in temperature would be greatest in? CORRECT ANSWERS: bone what shows the highest intensity value? CORRECT ANSWERS: SPTP As you perform a sonogram you switch from a 3.5MHz transducer to a 7.0 MHz transducer to image a superficial structure. Compared to the 3.5 MHz transducer what will the 7.0 MHz attenuation rate and wavelength be? CORRECT ANSWERS: Double the attenuation rate, one-half the wavelength.