Pulsed Echo Instrumentation Flashcards
1
Q
Major functions of Pulsed echo instrumentation
A
- The preparation and transmission of electrical signals to the transducer which create a cell beam
- The reception of electrical signals from the transducer
- Process the reflected information to clinically meaningful images for display
2
Q
Major components of ultrasound system
A
- Transducer
- Bean former
- Receiver
- Scan converter
- Recording and storage
- Display
- Master synchronizer
3
Q
Parts of the transmitter
A
Beam former and pulser
-Beam former function with transducers during transmission and reception
4
Q
Beam former
A
- An electronica device that receive the pulse or single electrical spike and distributes it to the numerous active elements of any array transducer (control electrical signals it to the transducer)
- It adjusts electrical spike voltages to reduce grating lobe artifacts in a process called apodization
- controls dynamic aperture
- During reception, establishes the correct time delays use for dynamic receive focusing
5
Q
Modern being formers
A
- Use advanced microprocessor technology in produce signals in digital format
- This is called digital beam former
6
Q
Advantages of digital beam formers
A
- System modifications and updates often require only software programming rather than design and manufacture of new hardware
- extremely stable, with no mechanical parts to fall out of calibration or wear out
- more versatile capable of using transducers with a wide range of frequencies
7
Q
What is a T/R switch
A
- Transmit and receiver switch
- The beam former has a special transmit and receive switch that is important during both transmission and reception
- It directs the driving in returning voltages during transmission in reception
- It protects the delicate receiver component
8
Q
What is a channel
A
- Individual signal paths for transmission and reception of the Sound beam
- A channel is made up of a single PZT element in the transducer, the electronics in the beam former/pulser and the wire that connects them
- Number of channels equals the number of transducer elements
9
Q
Pulser/transmitter
A
- The pulse or creates electrical signals (voltages) that excite the transducers PZT crystals and create sound beams
- The pulse (pulse generator) controls the strength (intensity), or amplitude, of the electricity striking the elements, as well as the pulse repetition frequency and pulse repetition period
10
Q
Transducer output
A
- output power/pulser voltage
- Adjustable by sonographer (magnitude of The pulser’s electrical voltage spike)
- Modifies the brightness of the entire image displayed
- Affects image brightness by altering the strength of the sound pulse that the transducer sends to the body
- Only the pulser controls the amount of power entering the patient
11
Q
What is an ultrasound transducer
A
- Converts one form of energy into another
- During transmission, electrical energy from the system is converted into a sound/acoustic energy
- During reception, the reflected sound pulse/acoustic energy is converted into electricity
12
Q
What two measurements are used to standardize the output gain?
A
- Thermal index
- Mechanical index
13
Q
Are frequency a amplitude related?
A
No
14
Q
And how does transducer output affect noise?
A
Increasing output power is the most common way to increase the signal to noise ratio
15
Q
Functions of master synchronizer
A
- Maintains and organizes the proper timing an interaction of the systems components
- Responsible for controlling the timing of the echoes, pays attention to one pulses are sent out and when they are received in order to determine depth of reflector, Insurers new pulses are sent out until the receiver received the previous pulse
- by paying attention to beam former and receiver
