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Son Ch. 4 prt. 1
Instruments: Principle 1
| Question | Answer |
|---|---|
| Is Principle 1 a one to one correspondence? | Yes |
| Physical beam forming is _____ _____ with displayed scan lines. | directly coupled |
| Principle 2 Virtual Beam Forming (VBF) does not rely on a one to one relationship. True or False? | True |
| Principle 2: Uses weakly focused or _______ transmit beams and computed reception "Beams". | Non-focused |
| One Operating principle is present in sonographic instruments. True or False? | False |
| A One to One correspondence between the echo stream from an emitted ultrasound pulse and its displayed scan line is which principle? | Principle 1 |
| Fewer pulses are required and transmission focusing isn't necessary and yet the entire resulting image is in focus. Which principle is this? | Principle 2 |
| Virtual Beam Forming (VBF) results in _____ image quality as compare to ______ . | Improve; Principle 1 |
| Images are not in focus throughout, in principle 2. | False (are in focus, and have improved quality) |
| List Principle 1's 5 parts... | Transducer; Beam Former; Signal Processor; Image processor; Display |
| What is the Pulse Echo Method? | Electrical energy is converted to acoustic; Acoustic is converted back to electrical |
| Sonographic equipment determines? | Echo Strength; Location of returning echoes: by direction and arrival time; Voltages represent received echoes |
| What is this Chapter about? | It explains how the machine puts the echoes together to produce an image. |
| The ____ ____ sends digitized echo voltage streams to the signal processor. | Beam Former |
| A Beam former consists of... | Pulser; Pulse delays; Transmit/receive switch; Analog to digital converters; Echo delays; Summer |
| Name the 7 functions of the Beam Former. | Generate Voltages that drive transducer; Determine prf, coding, frequency, and intensity; Scanning, focusing and apodizing the transmitted beam; Amplifying the returning echo voltages; compensating for attenuation; digitizing the echo voltage stream |
| What is a Pulser? | Where action BEGINS; Generates voltages that drive transducer; frequency of Voltage pulse determines the frequency of the resulting ultrasound pulse |
| A Pulser informs the ______ and the ______ when the ultrasound pulses were produced. | Reciever; Memory |
| Sequencing and phasing of array transducers are carried out by the ____ and ____ ____ . | Pulser; Pulse Delays |
| The _____ produces ______ _______ that drive the transducer, forming the beam that sweeps through the tissue to be imaged. | Pulser; Electric Voltages |
| PRF must be ______ to provide proper display of returning echoes. | Limited |
| the PRF is determined by what? | The Pulser |
| Does the Operator normally have direct control of the prf? | No; the pulser adjusts it appropriately for imaging depth (ranges 4-15 KHz and 5- 30 for Doppler) |
| The Ultrasound PRF is equal to the voltage PRF. True or False? | True |
| One Voltage pulse produces one ultrasound pulse. True or False? | True |
| PRF must be set high/low enough to receive information for the display | High |
| PRF produces a continuous/non-continuous image. | Continuous |
| PRf must be ______ to produce an unambigous image on the display. | Limited |
| The Echoes from one pulse must be received before the next pulse is sent. True or False? | True |
| Name the Imaging Depth formula. | Depth(cm) times prf (khz) greater than or equal to 77 (cm/ms) |
| Imaging depth multiplied by the PRF MUST exceed 77. True or False? | False (MUST NOT) |
| What occurs if imaging depth exceeds 77? | Ambiguity occurs |
| As Operating frequency is reduced ____ ____ increases and ____ is reduced to avoid echo misplacement. | penetration depth; prf |
| For deeper imaging, a reduction in _____ ____ may be created by using a lower prf. | Frame Rate |
| Pulse and pulse delays carry out the following tasks... | Sequencing; Phase delays; Variations in pulse amplitudes |
| The Beam Former controls what? | Sequencing and phasing; Beam scanning; beam steering; transmit focusing; dynamic aperture and apodization |
| the greater the voltage amplitude produced by the ________, the greater the amplitude of the ultrasound pulse produced by the transducer. | Pulser |
| Pulser Voltages - | Range up to 100 volts; shown as output level on display; usually shown in dB; 100% = 0 dB |
| What is Acoustic output? | Amount of acoustic energy produced by machine |
| The ______ the acoustic output, the _______ risk of producing a biological effect. | Higher; greater |
| Acoustic output can be reduced by increasing the receiver gain. True or False? | True |
| What is a channel? | An independent signal path consisting of a transducer element delay and possibly other electronic components. |
| Increased number of channels allows ____ _______ control of beam characteristics | precise control |
| Modern sonography systems typically consists of... | 64, 128 and 192 channels |
| The number of channels exceeds the number of elements in the transducer. True or False? | False; does not exceed |
| T/R switch protects what? | Sensitive input components of the amplifiers from the large driving voltages from the pulser. |
| What are Electrical voltages produced by the pulser sent? | to the Beam Former |
| The Beam former sends electrical voltages to the __________. | Transducer |
| Transducer converts the electrical pulses to acoustic pulses. True or False? | True |
| Sound is reflected off of structures and return to the transducer in the form of sound echoes. True or False? | True |
| Name the full route of energy. | Electric voltages by pulser are sent to the beam former -> transducer converts to acoustic -> sound is reflected to transducer again as echoes -> transducer converts echoes into electrical energy. |
| BEFORE/AFTER the electrical pulse goes to the transducer the beam former does what? | Before; sequencing and phasing operations; scanning; steering; transmit focusing; dynamic aperture and apodization |
| BEFORE/AFTER the echoes are converted back to electric energy, the beam former performs dynamic receive focusing | After |
| Define Reciever | Reception portion of the beam former |
| What does the Receiver perform? | amplification; compensation; compression; demodulation; rejection |
| Amplifiers increase voltage amplitudes. True or False? | True |
| The beam former has 2 amplifiers for each channel. True or False | False; One amplifier for each channel |
| Define amplification. | The conversion of the small voltages received from the transducer to larger ones. |
| Amplifiers increase voltage amplitude, and this increase is called? | Gain |
| Gain control determines how much _____________ is accomplished in the amplifier. | Amplification |
| gain is what to what? | Output voltage to input voltage |
| Does gain compensate for attenuation? | Yes |
| input is energy that? | goes into the amplifier |
| output is energy that? | comes out of the amplifier |
| PR = (VR)squared is what formula? | the Gain Formula |
| What does Compensation do? | It equalizes differences in received echo amplitude because of the reflector depth. |
| What are 5 other names for Compensation? | Gain Compensation; Time-varied gain (TVG); Sensitivity-time control (STC); Time-gain compensation (TGC); Depth-gain compensation (DGC) |
| Reflectors or echoes from a _______ depth are attenuated more than echoes from a _______ depth. | greater; shorter |
| The DGC curve is set by? | the OPERATOR |
| what does ADC stand for? | Analog to digital converter |
Created by:
A-Hole
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