Algebraic model for negative focused ultrasound beam width

Algebraisk model for negative fokuseret ultralyd stråle bredde

Jakobsen, Christian Elmholt

4. term

Biomedical Engineering and Informatics, Master

2016

2016-05-31

74

Ultralydsbilleddannelse bruger typisk ufokuserede eller fokuserede stråler til at indsamle information fra væv. Men hastigheden for dataindsamling er nået en grænse, og der er behov for nye teknikker. Negativt fokus, hvor en negativ brændvidde giver en bredere stråle, har i nogle tilfælde vist potentiale til at øge den parallelle fokusering i ultralyd, men det er mindre velbeskrevet end de andre stråletyper. Dette projekt udvikler en enkel algebraisk model, der forbinder tre centrale faktorer – aperturens størrelse, den negative fokale afstand og rækkevidde (dybde) – for at bestemme strålebredde. Modellen viser, at strålebredde kan forstås som en projektion af aperturen. Den er baseret på en ny teknik til at simulere ultralydsstråler og er valideret med målinger af strålebredde fra to transducere (ultralydsprober) med god overensstemmelse. Modellen har potentiale til at samle de adskilte teorier for ufokuserede, fokuserede og negativt fokuserede stråler i én ramme.

Ultrasound imaging typically uses unfocused or focused beams to collect information from tissue. However, acquisition speed has reached a limit, and new techniques are needed. Negative focus, which uses a negative focal distance to produce a wider beam, has in some cases shown potential to enhance parallel focusing in ultrasound, but it is less well understood than unfocused and focused beams. This thesis develops a simple algebraic model that links three key factors—aperture size, negative focal distance, and range (imaging depth)—to the resulting beam width. The model shows that beam width can be interpreted as a projection of the aperture. It is built on a newly developed technique for simulating ultrasound beams and is validated with beam-width measurements from two transducers, showing good agreement. The model has the potential to bring the separate theories for the three beam types together into one framework.

[This abstract was generated with the help of AI]

Negativ Fokus Ultralyd

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Jakobsen, Christian Elmholt:

• Algebraic model for negative focused ultrasound beam width (2016)