Ultrasound Physics Registry Preparation

Overview

• Review of SP board questions for ultrasound physics registry exam.
• Opportunity to practice answering questions with explanations provided.

Key Topics Covered

Ultrasound Beam Characteristics

• Focus: Narrowest part of the beam.
• Focal Zone: Region around the focus, characterized by being relatively narrow.
• Focal Length vs. Focal Zone: Focal zone spans the Fresnel and Fraunhofer zones.

Doppler Effect

• Frequency Shift and Doppler Equation: Frequency shift increases with higher transmit frequency.
• Turbulent Flow Prediction: Determined by Reynolds number.

Color Doppler Tips

• Enhancing deep flow visibility: Decrease ultrasound frequency.

Image Resolution

• Axial Resolution Improvement: Increase bandwidth.

Power Doppler

• Cannot determine blood flow direction, only presence of flow.

Transducer Characteristics

• Transducer B has a cosine of 0.5.

Acoustic Artifact

• Acoustic Speckle: Noise from small amplitude sound wave interference.
• Noise: Small amplitude echoes from electrical interference.

Bit Depth in Imaging

• 4 bits required for 15 different shades of gray.

Line Density

• Line density is the scan lines per centimeter.

Temporal Resolution

• Greatest improvement by decreasing depth and reducing scan lines.

Patient Interaction

• Stop examination immediately if patient refuses.

Color Maps in Imaging

• Common Color Maps: Variance and velocity.
• Velocity Scale: 17 cm/s represents average velocity.

Sonography Metrics

• 3D Sonography: Volume rate represents volumes displayed per second.

Frame Rate Perception

• Human eye perceives without flickering at 30 frames per second.

Binary Numbers

• Consist only of ones and zeros.

Universal Precautions

• Do not wash gloves for reuse; always use new gloves between patients.

Frame Rate Calculation

• Frame rate is the reciprocal of time taken to create an image; 1/20th of a second results in 20 Hz.

Temporal Resolution Improvement

• Improved with low line density, due to fewer scan lines per frame.

Conclusion

• This session covered the first set of 25 questions.
• Stay tuned for additional questions and further study materials.

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