Phased Linear Array
Time delays/phase shifters Focus
Ultrasound transducers
2D ultrasound phased array
1D imaging array
2D therapy array
Goals for Ultrasound Therapy Array Fabrication
2D phased arrays with 1000+ elements Geometric focusing, curved apertures Designs vary for different targets (size, frequency, etc.)
The Problem
Vacuum Bag Technique: RTV Mold Populated with 96 Elements
7mm x 7mm x 2.8mm elements - Resonance frequency = 617kHz
Array Bonding in Oven
Vacuum Bag Technique
Removes air pockets in epoxy/substrate interface and epoxy/PZT interface Maintains pressure while epoxy cures When combined with improved preparation and processing, this solves the element bonding problem Lateral modes - subdicing required
96 Element Array Prototypes
Simulated vs. Measured
Measured Focus
Excitation frequency = 617kHz
Measured Focus
Excitation frequency = 617kHz
Measured Focus
Excitation frequency = 617kHz
Measured Focus
Excitation frequency = 617kHz
Measured Multiple Focus
Excitation frequency = 617kHz
Measured Multiple Focus
Excitation frequency = 617kHz
Measured Focus
Excitation Multiple frequency = 617kHz
Conformal Ultrasound Arrays
Constructed on flexible substrates Adjusted to framework defined by the applicator: Flat panel approximations to larger curved structures Hybrid therapy devices which combine RF and ultrasound
Curved US Array Prototype (Conformal Phased Array)
630kHz US array (2.25mm thick)
980kHz US array (2 mm thick)
1.2MHz US array (1.4 mm thick)
Drug release from temperature sensitive liposomes at 42C
% Doxorubicin Released % Doxorubicin Released
60 50 40 30 20 10 0
0 1000 2000 3000 4000
New Formulation: 50% in 20 sec
Conventional Time (seconds)
Time (seconds)...