Pulse Ultrasound Summary

Components of Pulse Ultrasound

• Pulse ultrasound consists of cycles with quantities of on-time (talking) and off-time (listening).
• On-time and off-time define the transmit and receive functions.

Key Parameters

• Important parameters include:
  • Pulse Repetition Frequency
  • Pulse Repetition Period
  • Pulse Duration
  • Duty Factor
  • Spatial Pulse Length

Pulse Duration

• Definition: Time from the start to the end of a pulse (does not include off-time).
• Unit: Microseconds (symbol: PD).
• Equation: $PD = \text{Number of Cycles} \times \text{Period}$
• Not adjustable by the sonographer.
• Relationship:
  • Long duration = many cycles/long period.
  • Short duration = fewer cycles/short period.

Frequency and Period Relationship

• Frequency and period are reciprocally related: $\text{Frequency} \times \text{Period} = 1$
• Pulse Duration (PD) can also be expressed as: $PD = \frac{\text{Number of Cycles}}{\text{Frequency}}$
• Inversely related: Increasing frequency decreases pulse duration, and vice-versa.

Special Pulse Length (SPL)

• Definition: Distance covered during one complete pulse.
• Equation: $SPL = \text{Number of Cycles} \times \text{Wavelength}$
• SPL is directly related to the number of cycles and wavelength.
• Inversely related to frequency, similar to pulse duration.