Effect of phase errors on field patterns generated by an ultrasound phased-array hyperthermia applicator.

Area of Science:

• Medical Physics
• Biomedical Engineering
• Acoustic Imaging

Background:

• Ultrasound phased arrays are used for hyperthermia treatment.
• Phase errors can affect the accuracy of focused ultrasound fields.
• Understanding error tolerance is vital for clinical application.

Purpose of the Study:

• To investigate the impact of phase quantization and random phase errors on ultrasound phased array hyperthermia applicator performance.
• To determine the stability and limitations of synthesized field patterns under various phase error conditions.

Main Methods:

• Simulated phase quantization errors from four-bit to one-bit.
• Introduced Gaussian distributed random phase errors.
• Analyzed the resulting field patterns and power deposition.

Main Results:

• Simulated patterns degrade with increasing phase errors (quantization and random).
• Foci shape and position remained largely unchanged despite significant errors.
• Useful power deposition patterns were achieved even with one-bit quantization or large random phase errors (52° std. dev.).

Conclusions:

• Ultrasound phased array hyperthermia applicators demonstrate remarkable stability against substantial phase errors.
• The power deposition patterns are relatively insensitive to phase errors, suggesting resilience in biological tissues.
• These findings support the feasibility of using such applicators in clinical settings with potential error tolerances.