A transformation based method to design ultrasound array

Area of Science:

• Medical physics
• Acoustic imaging
• Ultrasound technology

Background:

• Optimal apodization is crucial for achieving desired lateral field distributions in medical ultrasound.
• The lateral field's dependence on focal distance makes finding optimal apodization a complex and arduous task.

Purpose of the Study:

• To develop an efficient suboptimal method for calculating optimal apodization at any focal distance.
• To overcome the computational challenges associated with traditional optimal apodization determination.

Main Methods:

• Introduced a nonlinear transformation to calculate optimal apodization at any distance based on known optimal apodization at a reference distance.
• Leveraged the expression of lateral field distribution as a Fourier transform of a nonlinear function of aperture weighting.

Main Results:

• Successfully mapped apodization for desired beam patterns to apodization maintaining similar lateral field properties.
• Demonstrated precision better than 9% for a 50-element linear array at distances D and D/2.
• Validated the method's effectiveness in optimization problems like minimizing sidelobe levels.

Conclusions:

• The proposed nonlinear transformation offers an efficient approach to determine optimal apodization for medical ultrasound imaging.
• This method simplifies the process of achieving desired beam patterns across various focal distances.
• The technique is particularly valuable for specific optimization tasks and provides acceptable results in broader applications.