Ultrasound Physics: Instrumentation and System Components

Comprehensive vocabulary flashcards covering the components and functions of an ultrasound system, including the pulser, beam former, and the five operations of the receiver.

Master Synchronizer

The component of the ultrasound system that maintains and organizes the proper timing and interaction of the system's components.

Pulser

The component that functions during transmission to create electrical signals that excite the transducer's PZT crystals and create sound beams; it determines the amplitude, PRP, and PRF.

Beam Former

A sophisticated electronic device that receives the pulser's single electrical spike and distributes it to the numerous active elements of an array transducer.

Receiver

The component that transforms the electrical signals from the transducer (produced by reflected echoes) into a form suitable for display.

Signal-to-Noise Ratio

A comparison of the meaningful information (signal) in an image to the amount of contamination (noise).

Amplification

The first function of the receiver, also known as receiver gain, where each electronic signal returning from the transducer is made larger.

Compensation

The second function of the receiver, often called Time Gain Compensation (TGC), used to create an image that is uniformly bright from top to bottom by correcting for attenuation.

Compression

The third function of the receiver that reduces the total range of signals between the smallest and largest while maintaining the relationship between them.

Demodulation

The fourth function of the receiver, a two-part process that changes the electrical signals into a form more suitable for display on a monitor.

Rectification

The first step of demodulation that converts all negative voltages into positive voltages.

Smoothing

The second step of demodulation, also called enveloping, which places a smooth line around the 'bumps' in the signal and evens them out.

Reject

The fifth function of the receiver that allows the sonographer to control whether low-level gray scale information (noise) will appear on the display.

Output Power

A control that determines the strength of the signal sent by the transducer into the body, affecting patient exposure.

Overall Gain

A control that increases or decreases the strength of the signal received by the transducer from the body after it has returned.

ALARA

Stands for 'As Low As Reasonably Achievable,' the principle used to minimize patient exposure by adjusting output power and receiver gain appropriately.