SPI Test A16 Radiology Exam Questions & Answers

SPI Test A16 Radiology Exam Questions & Answers-Which of the following console can be used to increase the number of scan lines used in color image? A. rejection B. Persistence C. Overall gain D. Output Power - B. Persistence feedback: Increased persistence setting increase the number of scan lines used to create the image and reduce the frame rate. What leads to the increased propagation speed of sound in the media in which it travels? A. Increased frequency B. Increased stiffness C. Increased PRF D. Increased density - B. Increased stiffness Feedback: The speed is determined by the media in which the sound travels. Increased stiffness of the media is related to an increase in propagation speed. Increased density of the media will reduce propagation speed. Frequency and PRF are US system parameters and are not factors that determine propagation speed of the media. ___________ is the predominant factor causing attenuation of the US beam and this can be counteracted by _________________. A. Sound absorption, increasing the TGC settings for the near field B. Sound absorption, increasing the TGC settings for the far field C. Refraction, scanning the breast from a different angle D. Reflection, reducing the overall gain setting - B. Sound absorption, increasing the TGC settings for the far field. Feedback: Sound absorption is the predominant factor causing attenuation of the US beam and this can be counteracted by increasing the TGC settings for the far field. Which of the following is true regarding continuous wave transducer structure and function? A. CW probes have a single PE element B. Higher frequency CW probes have the highest duty factor % of all CW probes C. CW probes usually have no backing material except a pocket of air posterior to the element D. CW probes usually require a double thickness of matching layer compared to a PW probe of the same frequency. - C. CW probes usually have no backing material except a pocket of air posterior to the element. Feedback: CW probes have two elements. one of transmission and one for receiving signals. The matching layer thickness is related to the wavelength of the probe. CW vs. PW does not affect matching layer thickness. All CW probes have a duty factor of 100% because the beam is constantly "on" (does not pulse on or off). A CW probe does not need a backing because it is constantly producing an ultrasound pulse and ring down between pulses is not a concern. The narrowest portion of a beam produced by a focused ultrasound transducer is: A. The focal point B. The Fraunhofer zone C. The first centimeter of the beam that leaves the transducer D. The Fresnel zone - A. The focal point Feedback: The narrowest portion of a beam produced by a focused ultrasound transducer is at the focal point.