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21 Cards in this Set
- Front
- Back
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1. Ultrasound transducers operate according to the principle of?
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a. Snells Law
b. Doppler's Law c. Magnetostrictive Effect d. Piezoelectricity e. Impedance Effect |
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2. Operating frequency of an element is determined by its?
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a. Thickness
b. Width c. Bandwidth d. Voltage e. None of the above |
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3. Damping will result in?
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a. Decrease in SPL
b. Decrease in PD c. Improved resolution d. All of the above |
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4. An increase in frequency produces?
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a. Decrease in detail resolution
b. Increase in detail resolution c. Increase in penetration d. Both A and B c. Both B and C |
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5. Which of the following is approximately equal to the number of cycles in a pulse?
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a. Fractional bandwidth
b. Quality factor c. Amplitude d. Bandwidth |
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6. The range of frequencies involved in an ultrasound pulse is called?
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a. Operating frequency
b. Dynamic Range c. Beam width d. Quality factor e. Bandwidth |
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7. Transducer assemblies are also called?
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a. Scanheads
b. Probes c. All of the above d. None of the above |
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8. The impedance of PZT is approx. 30 million rayls and the impedance of skin is about 1.6 million rayls. For ultrasonic imaging which of the following would be the optimal impedance of matching layer and coupling medium to avoid a high reflection of sound at the skin boundary?
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a. 14 million - 25 million
b. 20 million - 15 million c. 14 million - 45 million d. 14 million - 1 million |
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9. What is the name of the region that lies beyond a distance of one near zone lenght?
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a. Fresnal zone
b. Far field c. Focal zone d. Near field e. Area closest to the transducer |
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Which of the following facilitate the transmission of sound across the transducer skin boundary?
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a. Matching layer
b. Damping layer c. Coupling layer d. Both A and C e. All of the above |
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11. Beam width will___ along the near zone
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increase
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12. Which of the following are factors that influence the beam width @ any location
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a. frequency
b. aperture c. distance from the transducer d. a & c e. all of the above |
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13. Elements are made piezolecetric by placing them in a strong magnetic field & exposing them to a high temperature. What is the max. temp. that can be reached w/out losing its piezoelectricity
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a. Pzt
b. piezo point c. curie point d. voltage point e. none of the above |
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14. All of the following are other names for the transducer element except
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a. piezoelectric element
b. active element c. crystals d. scanhead element |
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15. Longer driving voltages of typically____ are used for Doppler tech.
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a. 1-3
b. 3-10 c. 5-15 d. 5-25 e. 10-20 |
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16. Operating frequency is determined by
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a. propagation speed of transducer element
b. element thickness c. bandwidth d. a & b e. all of the above |
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17. Damping
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a. increase the DF
b. decrease the F c. increase the # of cycles in a pulse d. decrease the impedance mismatch between 2 mediums |
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18. Thinner transducer elements operate @____ operating frequency
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a. lower
b. higher c. element thickness has no dependence on Fo d. none fo the above |
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19. Single-element disk transducers produce an artifact called
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a. side lobes
b. beam lobes c. fresnol zone d. side thickness e. beam width rays |
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20. If aperture increases, near zone length_________
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a. is unchanged
b. increased c. decreased d. aperture size has no effect on NZL |
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21. As a pulse travels through the near zone, its width____, & as it travels through the far zone, its width
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a. increased, increased
b. increased, decreased c. decreased, decreased d. decreased, increased |
