Abstract: A radio frequency applicator for a thermoacoustic imaging system is disclosed. The applicator includes, a waveguide with an internal radio frequency source, wherein the waveguide has an opening, an electromagnetic matching layer coupled to the waveguide and proximate to the opening, and an acoustic absorbing layer that is coupled to the matching layer.

Abstract: A method for manufacturing a radio frequency (RF) applicator which includes covering a ceramic insert with a coating, wherein the ceramic insert has dimensions that substantially match an internal volume of an open-ended, hollow waveguide, and wherein the ceramic insert has a recess therein configured to accept a radio frequency emitter, heating the waveguide to a temperature that is above a melting point of the coating, placing the coated ceramic insert into the internal volume of the heated waveguide, wherein the internal volume is completely filled except for the recess, and cooling the waveguide, ceramic insert, and coating to a temperature below the melting point of the coating so that the coating solidifies and fills gaps between facing surfaces of the insert and the waveguide.

Abstract: A multi-modality fatty tissue mimicking material for phantoms for use with thermoacoustic imaging, ultrasound imaging and magnetic resonance imaging, which includes: an aqueous mixture of a 3% to 18% thickening agent, a 1% to 30% protein powder, a 0.1% to 2% ionic salt, a 30% to 85% water, and a 0% to 60% oil by weight, wherein the oil percentage corresponds to the fat percentage in tissue, further wherein the ionic salt percentage corresponds to an imaginary part of complex permittivity in tissue, and further wherein the water, oil and protein powder percentages correspond to the real part of complex permittivity in tissue.

Abstract: A method for manufacturing a radio frequency (RF) applicator which includes covering a ceramic insert with a coating, wherein the ceramic insert has dimensions that substantially match an internal volume of an open-ended, hollow waveguide, and wherein the ceramic insert has a recess therein configured to accept a radio frequency emitter, heating the waveguide to a temperature that is above a melting point of the coating, placing the coated ceramic insert into the internal volume of the heated waveguide, wherein the internal volume is completely filled except for the recess, and cooling the waveguide, ceramic insert, and coating to a temperature below the melting point of the coating so that the coating solidifies and fills gaps between facing surfaces of the insert and the waveguide.

Abstract: A radio frequency applicator comprises an open-ended, hollow waveguide having an aperture therein. A solid insert is positioned within the waveguide. The solid insert has a recess formed therein that is aligned with the aperture. Filler material is provided between facing surfaces of the waveguide and the insert to fill gaps therebetween. A radio frequency (RF) source extends through the aperture and into the recess and is configured to generate RF energy pulses.

Abstract: A radio frequency applicator comprises an open-ended, hollow waveguide having an aperture therein. A solid insert is positioned within the waveguide. The solid insert has a recess formed therein that is aligned with the aperture. Filler material is provided between facing surfaces of the waveguide and the insert to fill gaps therebetween. A radio frequency (RF) source extends through the aperture and into the recess and is configured to generate RF energy pulses.

Abstract: A thermoacoustic imaging method comprises administering a thermoacoustic imaging contrast agent to a subject, the thermoacoustic imaging contrast agent having a viscosity higher than blood and substantially similar to a viscosity of a known computed tomography (CT) or magnetic resonance imaging (MRI) contrast agent; and imaging the subject with a thermoacoustic imaging system. The thermoacoustic imaging contrast agent may comprise an ionic solution and thickening agent mixture, with an optional heating agent. The ionic salt makes 0.5% to 5.0% of the ionic solution by weight and the remainder of the ionic solution is water. The thickening agent makes 3% to 50% of the mixture by weight.

Abstract: Some embodiments of the disclosed subject matter provide systems, devices, and methods for tuning resonant wavelengths of an optical resonator. Some embodiments of the disclosed subject matter provide systems, devices, and methods for tuning dispersion properties of photonic crystal waveguides. In some embodiments, methods for tuning a resonant wavelength of an optical resonator are provided, the methods including: providing an optical resonator having a surface; determining an initial resonant wavelength emitted by the optical resonator in response to an electromagnetic radiation input; determining a number of layers of dielectric material based on a difference between the initial resonant wavelength and a target resonant wavelength and a predetermined tuning characteristic; and applying the determined number of layers of dielectric material to the surface of the optical resonator to tune the initial resonant wavelength to a tuned resonant wavelength.

Abstract: Some embodiments of the disclosed subject matter provide systems, devices, and methods for tuning resonant wavelengths of an optical resonator. Some embodiments of the disclosed subject matter provide systems, devices, and methods for tuning dispersion properties of photonic crystal waveguides. In some embodiments, methods for tuning a resonant wavelength of an optical resonator are provided, the methods including: providing an optical resonator having a surface; determining an initial resonant wavelength emitted by the optical resonator in response to an electromagnetic radiation input; determining a number of layers of dielectric material based on a difference between the initial resonant wavelength and a target resonant wavelength and a predetermined tuning characteristic; and applying the determined number of layers of dielectric material to the surface of the optical resonator to tune the initial resonant wavelength to a tuned resonant wavelength.