Which target group in this image of a tissue-mimicking phantom is used to evaluate axial resolution?
Answer(s): B
In the given image of a tissue-mimicking phantom, Option B (yellow box) is used to evaluate axial resolution. Axial resolution refers to the ability of the ultrasound system to distinguish between two structures that are close to each other along the path of the ultrasound beam (i.e., parallel to the beam). The targets in Option B are typically aligned in such a way to test the system's capacity to differentiate between structures that are situated closely together along the beam's axis.
ARDMS Sonography Principles and Instrumentation guidelines"Sonography: Principles and Instruments" by Joan P. Baker and Marveen Craig
Which action may reduce the number of lines in a frame without a loss of temporal resolution?
Narrowing the field of view reduces the number of scan lines that need to be processed per frame. This allows the ultrasound system to maintain or even increase the frame rate without compromising temporal resolution. Temporal resolution, which refers to the system's ability to depict motion accurately, is directly related to the frame rate. Reducing the field of view ensures fewer lines are needed to create each image, thus preserving the frame rate and temporal resolution.
ARDMS Sonography Principles and Instrumentation guidelinesKremkau, F. W. (2015). Diagnostic Ultrasound: Principles and Instruments.
Which describes the reflected frequency when a reflector is moving toward the sound source?
Answer(s): A
When a reflector (such as red blood cells) is moving toward the sound source, the frequency of the reflected sound waves increases. This phenomenon is known as the Doppler effect. The frequency shift occurs because the motion of the reflector compresses the sound waves, leading to a higher frequency than the emitted frequency. This increased frequency is what the Doppler ultrasound system detects and uses to calculate the velocity of the moving reflector.
ARDMS Sonography Principles and Instrumentation guidelinesHoskins, P. R., Thrush, A., Martin, K., & Whittingham, T. A. (2010). Diagnostic Ultrasound: Physics and Equipment.
Which method of sanitizing the transducer would damage piezoelectric crystals?
Answer(s): D
Autoclaving involves high-pressure steam at high temperatures, which can damage the delicate piezoelectric crystals within the ultrasound transducer. These crystals are responsible for converting electrical energy into sound waves and vice versa. Exposure to the extreme conditions of an autoclave can cause thermal and mechanical damage to the crystals, rendering the transducer ineffective.
ARDMS Sonography Principles and Instrumentation guidelinesZagzebski, J. A. (1996). Essentials of Ultrasound Physics.
Which statement characterizes the primary difference between image A and image B?
The primary difference between Image A and Image B is the overall gain setting. Gain controls the amplification of the received echoes. A lower gain setting results in a darker image with less overall brightness, which is evident in Image A compared to Image B. Image B appears brighter, indicating a higher gain setting that amplifies the echoes more, making the structures appear more prominently.
ARDMS Sonography Principles and Instrumentation guidelinesHedrick, W. R., Hykes, D. L., & Starchman, D. E. (2005). Ultrasound Physics and Instrumentation.
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