FREE ARDMS Sonography Principles and Instrumentation Questions and Answers
What happens to the visual display when a mechanical transducer's PZT crystal is damaged?
The PZT crystal serves as the only active component in mechanical transducers. Therefore, the entire visual display is lost when the crystal is destroyed.
When depth is raised, which of the following happens?
The frame rate drops as depth increases. Temporal resolution also declines as a result. However, the image has more details visible at a deeper level in the body. According to the 13-microsecond rule, the go-return time (time of flight) increases by 13 microseconds for every 1 cm deeper. Tframe is the result of multiplying the quantity of imaging pulses by the time between pulses; hence, deeper imaging yields a longer Tframe.
Active elements in 3D transducers are arranged in a particular pattern, or _________.
A 3D transducer is essentially a 2D transducer with a checkerboard pattern of PZT crystals. A 3D transducer typically contains thousands of different active parts. The final image is created from the data collected while the acoustic beam is electrically guided and focused.
Many PZT crystals are placed in an arched line with ______ transducers.
Convex array transducers have active elements (PZT crystals) arranged in a rainbow-like arched line. Convex arrays can also be referred to as curved arrays or curvilinear array transducers. The exhibited image has a blunted sector at the top. Alternatively, the image produced by linear array transducers with active elements placed in a straight line shows a rectangular shape. A sector-shaped image is produced when the active elements of an annular array are placed in a bullseye pattern.
A sonographer is using an annular array transducer to do an examination. In the near field of the image that is being presented, there is a horizontal band of dropout. Which PZT crystal ring damage does this most likely relate to?
An annular array transducer's active components are arranged in a bullseye pattern. The exhibited image will have a horizontal band of dropout in the near field when the innermost element is damaged. The mid-image display corresponds to the middle ring. In the image being exhibited, the far field corresponds to the outermost crystal. When a linear or convex array transducer is destroyed, a vertical band of dropout would appear beneath the site of the harmed active element.
The PZT crystal in a linear phased array transducer is divided into 280 distinct active elements. This transducer has how many channels?
It contains 280 channels in this transducer. There is a channel for every active component. The PZT crystal, system electronics, and connecting wire make up a channel. The connection that connects each crystal to the system electronics enables each element to be individually activated, creating a sound wave that may be transmitted into the body. This enables the array transducer's electronic steering and focusing.
The sonographer increased output power by changing system settings. Which of the subsequent takes place?
The total gain and brightness of the projected image rise as output, or transmit, power is increased. Active elements also experience a higher voltage. Greater picture penetration is another effect of this increase in energy. The sonographer should be aware of the ALARA principle and comprehend that as output power increases, more energy is applied to the patient's body.