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SPI Ultrasound Physics Finals Study Guide.pdf
Typology: Exams
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What do waves transfer from one location to another? - โ Energy Which of the following best describes sound waves? - โ Longitudinal, Mechanical wave As sound travels through a medium, what term best describes the effects of the medium on the sound wave? - โ Acoustic Propagation Properties Describe the term "Compression" - โ Squeezed Together Describe the term "Rarefraction" - โ Stretched Apart Name the 7 parameters that describe sound waves - โ Period Frequency Amplitude Power Intensity Wavelength Propagation Speed What is the horizontal axis of a graph called? - โ X-axis How many nanoseconds are in 9 seconds? - โ 9,000,000, Which of the following is not a measure of area? - โ Cubic Meters
List these metric terms in increasing order: - โ Micro Milli Deci Deca Hecto Mega All of the following are measures of length except: - โ Second Pair of waves are in phase, what occurs when these waves interfere? - โ Constructive Interference Sound can be characterized as: - โ Cyclical oscillation in certain variables Sound is best described as - โ A series of compressions and rarefraction Which of the following are considered acoustic parameters? - โ Frequency Period Sound must propagate through a - โ medium Name the 3 acoustic variables - โ Pressure Density Distance What are the units of "Pressure" - โ Pa How are the height of a person and the color of their automobile related? - โ Unrelated How much bigger is a billion than a million? -
The pulse repetition frequency (PRF) is the - โ Reciprocal of pulse repetition period (PRP) What is the pulse duration equals to? - โ Period multiplied by the number of cycles in the pulse If all the factors remain unchanged, what happens to the duty factor, when the pulse repetition frequency increases? - โ Increases What happens to the pulse duration when a sonographer decreases the maximum imaging depth in an ultrasound scan? - โ Remains the same In diagnostic imaging, what establishes the pulse repetition frequency? - โ The source of the sound What are the units of pulse repetition frequency (PRF)? - โ 1 /seconds Using a specific transducer, what happens to the spatial pulse length as the sonographer increases the maximum imaging depth? - โ Remains the same Which of the following terms does NOT belong with the others - โ Shallow Imaging While using the same ultrasound machine and transducer, which of the following can a sonographer alter? - โ Pulse repetition period (PRP) Pulse repetition frequency (PRF) Duty Factor A sonographer adjusts the maximum depth of an ultrasound system. Which of the following also changes? - โ PRF & PRP
If all other factors remain unchanged, what happens to the duty factor when imaging depth increases? - โ Decreases A sonographer adjusts the depth of view of an ultrasound scan from 8 cm to 16 cm. Would each of the following parameters change? Period PRF Duty Factor PRP - โ Period = Remains the same PRF = Decrease Duty Factor = Decrease PRP = Increase What determines the pulse duration? - โ Source of the wave What event does Snell's law govern? - โ Refraction An ultrasound wave strikes an interface between two media at a 90 degree angle. The propagation speeds of the media are identical. However, the densities of the media are different. Which is true? - โ Reflection will definitely occur What are the units of the intensity reflection coefficient? - โ None Acoustic impedance is a property of the _______ and has the units of _______ - โ Medium, Rayls (Z) Increasing output power is the most common way to improve (increase) the signal-to- noise ratio. - โ True These five operations of the receiver must be performed in the appropriate order for the system to function properly, please rank them: - โ Amplification
The _______, of an analog scan convert is excellent because of the large number of storage elements within the matrix - โ Spatial resolution The dynamic range of a system: - โ Is the ratio, between the largest and smallest signals which is accurately measured Gray scale systems typically use _______ as a means of signal dynamic range reduction. - โ Compression Which of this statements regarding a bit of computer memory is false? - โ It is a smallest element of an image Is the following a form of information usually digital or analog? The signal from the transducer to the receiver _______ - โ Analog An uncompressed signal has a dynamic range of 90 dB. the signal undergoes 30 dB of compression. What is the dynamic range of the compression signal? - โ 60 dB (Subtract) Which of the following statements regarding a pixel is false? - โ It displays up to 3 gray shades simultaneously The acronym TGC denotes - โ Time Gain Compensation Which of the following is not true about spatial compounding? - โ Can be performed with a mechanical transducer Demodulation is a process of: -
โ Changing an electrical signal's form Which of these components typically has the lowest dynamic range? - โ Display All of the following are consistent with an image containing only black and white and no other shades of gray except: - โ Wide dynamic range The process of demodulation incorporates which of the following tasks? - โ Enveloping Rectification What is the primary disadvantage of video tape and computer this methods of image archiving? - โ The information is vulnerable to erasure when exposed to strong magnetic field Why are sonographic images usually compressed before sending to PACS? - โ Reduce the time to transmit the image Dynamic frequency tuning uses only _______ frequency reflections to create the superficial portion of the image and _______ frequency signals are used to create deeper portions of the image. - โ High Lower Where does code excitation takes place? - โ In the pulser With frequency compounding, how many pulses are transmitted down each scan line? - โ 1 Which of the following technologies uses long sound pulses to create an image? - โ Code excitation In modern Elastography, how are the tissues deformed? - โ Automatically Which of these is binary number? -
โ Three dimensional real time image Which of the following forms of focusing is different from the others? - โ Dynamic receive True or False? The curved pattern of delays in the electrical spikes used in a phased array transducer focuses the beam during reception. - โ False All of the following describe dynamic receive focusing EXCEPT - โ may be used by single crystal transducers How are the PZT crystals excited when using an ultrasound system with linear sequential array transducers? - โ In a specific order Which of the following is best described as mechanically steered and multi-focus? - โ Annular phased array transducer Which imaging modality places dots of dissimilar gray scale on the display? - โ B-mode Which transducer possesses the best slice thickness resolution? - โ 1 1/2 dimensional arrays A linear sequential array transducer has 128 crystals. How many crystals are fired to create a single sound beam? - โ A small group True or False, As frame rate increase, the image quality may degrade. - โ True A sonographer, using a phased array ultrasound system, turns off the multi-focus feature. What is the most likely consequence of this action? - โ The temporal resolution improves A sonographer adjusts an ultrasound machine to double the depth of view from 5 cm to 10 cm. If the frame rate remains the same, which one of the following also changed? - โ Narrower Sector
Which of the following is consistent with increased or improved temporal resolution? - โ Higher frame rate A sonographer increases the line density from 1 line per degree of sector to 3 lines per degree of sector. What is the consequence of this action? - โ The temporal resolution decrease What is the primary advantage of multiple focal zones along each scan line of a two dimensional image? - โ Improved lateral resolution A sonographer changes an image's sector size from 90 to 45 degree. The frame rate remained unchanged. What else must have happened? - โ The line density was doubled