Sonographic Principles & Instrumentation I

These flashcards cover key concepts from the lecture on sonographic principles and instrumentation, including reflection, acoustic impedance, Snell's law, attenuation, and more.

What are the two main types of reflection in ultrasound physics?

Specular reflection and diffuse reflection.

What is acoustic impedance?

The resistance to the propagation of sound through a medium, described by the equation Z = ρ x c.

What happens when there is a difference in acoustic impedance at an interface?

Reflection occurs when there is a difference in acoustic impedance, with greater differences leading to greater reflection.

What is the equation for calculating reflection percentage?

% reflection = (z2 - z1)/(z2 + z1)^2.

What is normal incidence in ultrasound?

When the sound beam strikes the boundary between two media at a 90-degree angle.

What does Snell's Law describe?

It describes the angle of transmission at an interface based on the angle of incidence and propagation speeds of two media.

What causes attenuation in ultrasound?

Attenuation is caused by reflection, absorption, refraction, and destructive interference.

What is defined as 3dB of attenuation?

It represents the depth at which sound has lost half (50%) of its intensity.

What is the relationship between frequency and attenuation?

Higher frequencies result in more attenuation, while lower frequencies result in less attenuation.

How is half-value layer (HVL) defined?

HVL is the thickness of tissue required to reduce the intensity of the sound beam by one-half.