Unit 14: The Ultrasound System

Overview

• The ultrasound system consists of the computer, transducer, and display.
• It performs complex activities to create images, which is crucial for sonographers to understand.
• The unit covers the system from beam formation to image display.

Ultrasound System Components

• Beam Former: Includes the master synchronizer and pulser, sending out the beam.
• TR Switch: Directs the signal to and from the transducer.
• Transducer and Patient Interaction: Echoes return to the transducer and back through the system.
• Receiver: Where the echo signal is first processed.
• Image Processor: Converts signals into digital form and processes them for display.
• Display: Shows the final ultrasound image.
• Storage: Options include internal hard drive, USB, DVD, paper, or PACS.

Section 14.1: Beam Former

• Master Synchronizer: Ensures pulses do not overlap, allowing image creation.
• Pulser: Creates voltages sent to the transducer, controlling power exposure.
• Voltage levels affect image brightness and risk of bio effects.
• Beam Former Functions: Distributes voltages for electronic focusing and steering.
• TR Switch: Directs voltages correctly during transmit and receive modes.

Section 14.4: Receiver

• Known as the signal processor.
• Performs five key steps: Amplification, Compensation, Compression, Demodulation, and Rejection.
  • Amplification: Increases echo amplitudes; adjustable by sonographer.
  • Compensation: Adjusts for attenuation to even out image brightness; uses TGC sliders.
  • Compression: Reduces dynamic range of signal to fit into display range.
  • Demodulation: Automatic process to prepare signals for processing.
  • Rejection: Filters out weak, unwanted echoes.

Section 14.5: A to D Converter

• Converts analog signals from the receiver into digital form for processing.
• Uses binary code to represent analog signals as discrete digital values.

Section 14.6: Scan Converter

• Digital scan converters use computer technology to digitize image information.
• Pixels and Bits: More pixels improve spatial resolution; more bits improve contrast resolution.
• Pre-processing and Post-processing: Refers to signal processing during live scanning and after freezing images.

Section 14.7: Display

• Modern displays use LCD or OLED technologies providing better resolution and refresh rates.
• Displays allow for additional functions like image measurement and annotation.

Section 14.8: Storage

• PACS: Stores images digitally for easy access and remote view.
• DICOM Format: Standard format for medical images, ensuring compatibility across systems.
• Storage methods include internal drives, external media, and paper prints.

Additional Concepts

• ALARA Principle: Aim to use the lowest power settings to reduce patient exposure.
• Pre-set Usage: Important for setting appropriate power levels specific to exam types.
• Contrast and Brightness Adjustments: Monitor settings for optimal image viewing, not affecting stored image data.

Ensure to review activities and nerd check questions to solidify understanding of ultrasound system operations.