Pulsed Wave Operations and Transducers

These flashcards cover key concepts, definitions, and relationships related to pulsed wave operations and transducers as presented in the lecture, providing a comprehensive review for the exam.

What are the two components of a pulse in ultrasound?

Transmit (on) time and receive (off) time.

What is the Pulse Repetition Period (PRP)?

It is the time from the start of one pulse to the start of the next pulse, including both transmit and listening time.

What does the Pulse Repetition Frequency (PRF) signify?

It represents the number of pulses transmitted into the body by the ultrasound system each second.

How is Pulse Duration (PD) calculated?

PD is calculated as the number of cycles in a pulse multiplied by the period of the central frequency.

What is the typical clinical imaging range for Pulse Duration (PD)?

The clinical imaging PD ranges from 0.3 to 2.0 microseconds.

What relationship exists between PRF and PRP?

PRF and PRP are reciprocals, meaning that as one increases, the other decreases.

What is Bandwidth in the context of ultrasound?

It is the range of frequencies emitted by a transducer, specifically the difference between the highest and lowest frequency emitted.

What does the 13 μsec Rule state?

It takes 13 microseconds for sound to travel to a depth of 1cm and return, meaning 6.5 microseconds to get to the reflector and the same time to return.

What materials are commonly used in clinical transducers for their piezoelectric properties?

Lead zirconate titanate (PZT) is commonly used, along with quartz and tourmaline.

What is the Curie Point?

It is the temperature at which a material exhibits piezoelectric properties, crucial for the functionality of PZT.

What is the effect of damping material on ultrasound transducers?

Damping reduces the ring time of the pulse, which improves axial resolution but may decrease sensitivity.

What is spatial pulse length (SPL)?

SPL is the distance a pulse occupies in space from start to end.

Describe the far field in a sound beam.

The far field, or Fraunhofer Zone, is the region where the sound beam widens or diverges.

Explain the significance of the focus in an ultrasound beam.

The focus is the location where the sound beam diameter is smallest and the area of greatest intensity and lateral resolution.

What dictates the frequency of continuous wave ultrasound?

The frequency of sound emitted by a continuous wave probe equals the frequency of the electrical signal used to drive the active element.

What is Huygens' Principle?

It states that when waves interact, secondary spherical wavelets are created, combining constructively to form the hourglass shape of the main sound beam.