In one aspect, ultrasound-switchable fluorescence (USF) imaging systems are described herein. In some embodiments, such a system comprises an ultrasound source, a fluorophore excitation source, a contrast agent comprising a fluorophore, and an image recording device. The contrast agent, in some cases, comprises a fluorophore associated with a liposome carrier, wherein the contrast agent has a size of up to 1 μm. Further, in some implementations of a system described herein, the image recording device is controlled by a software trigger mode.

A method comprising: directing a continuous-wave source laser beam to an optical resonator that is impinged by acoustic waves, wherein said source laser beam is propagated through said optical resonator; and detecting a signal associated with said acoustic waves by monitoring, using an interferometer, transients in the optical phase in said propagated laser beam, wherein said transients are indicative of a waveform of said acoustic waves.

Provided is an apparatus configured to analyze a component of an object, the apparatus including a signal detection sensor including a light source configured to emit light to the object, a detector configured to detect a signal of light scattered or reflected from the object, an ultrasonic generator configured to transmit an ultrasonic wave toward the object at irregular ultrasonic transmission time intervals to modulate a frequency of the light emitted to the object, and a controller configured to control the ultrasonic transmission time intervals of the ultrasonic generator to be irregular, and a processor configured to control the signal detection sensor and analyze the component of the object based on the signal of light detected by the detector.

A method of imaging cancer stem cells comprises disposing a population of first ultrasound-switchable fluorophorms having a first switching threshold in the biological environment, the first ultrasound-switchable fluorophores being functionalized for attachment to a first biomarker expressed by the CSCs; disposing a population of second ultrasound-switchable fluorophorms having a second switching threshold in the biological environment, the second ultrasound-switchable fluorophores being functionalized for attachment to a second biomarker expressed by the CSCs; exposing the biological environment to an ultrasound beam to form an activation region; disposing one or more of the first and/or second ultrasound-switchable fluorophores in the activation region to switch the first and/or second fluorophores from an off state to an on state; exciting the first and second ultrasound-switchable fluorophores in the activation region with a beam of electromagnetic radiation; and detecting light emitted by the first and second ultrasound-switchable fluorophores.

Methods are disclosed herein for measuring local E-fields, B-fields, and/or temperature effects of an MRI scan utilizing an acousto-optical sensor. A method includes positioning the acousto-optical sensor at a location of a body or phantom; receiving, with an antenna of the acousto-optical sensor, MRI RF energy localized at the first location; interrogating, with a light source, and via an optical fiber, an acousto-optical sensor region of the acousto-optical sensor; detecting, with a photodetector, interrogation light reflected from the acousto-optical sensor region; and outputting one or more signals corresponding to the detected interrogation light reflected from the acousto-optical sensor region. The one or more signals can correspond to an E-field, a B-field, and/or a temperature of the received MRI RF energy at the first location. Additional methods can include mapping results of multiple measurements around an implant.

Provided is an apparatus configured to analyze a component of an object, the apparatus including a signal detection sensor including a light source configured to emit light to the object, a detector configured to detect a signal of light scattered or reflected from the object, an ultrasonic generator configured to transmit an ultrasonic wave toward the object at irregular ultrasonic transmission time intervals to modulate a frequency of the light emitted to the object, and a controller configured to control the ultrasonic transmission time intervals of the ultrasonic generator to be irregular, and a processor configured to control the signal detection sensor and analyze the component of the object based on the signal of light detected by the detector.

Certain implementations of the disclosed technology may include active marker devices, retrofits, systems, and methods for determining the position of interventional devices under MRI. A marker device is provided that utilizes an optical fiber, an acousto-optical sensor region that includes an electro-mechanical conversion assembly, and one or more antenna(e). The one or more antennae are configured to receive MRI radio-frequency (RF) electromagnetic energy and produce a corresponding electrical signal corresponding to the position. The acousto-optical sensor region may include a resonator and may be modulated by acoustic waves generated responsive to the electrical signal received from the one or more antennae. The acousto-optical sensor region may be interrogated by light via the optical fiber to determine the position of the device for providing an active marker in the MRI image.

A method for determining at least one parameter of interest of a material comprises directing, using a radio frequency (RF) applicator, one or more RF energy pulses into a region of interest, the region of interest comprising a material having a parameter of interest and at least one reference, the material and the reference separated by at least one boundary; detecting, using an acoustic receiver, at least one multi-polar acoustic signal generated in the region of interest in response to the RF energy pulses; processing the at least one multi-polar acoustic signal to determine an electric field strength at the boundary; calculating a voltage standing wave ratio (VSWR) of the one or more RF energy pulses; and determining the at least one parameter of interest of the material based at least on the determined electric field strength and the VSWR.

A heart rate detection system includes a light source outputting a light beam, an acousto-optical sensing element having a crystalline material, and a light analysis module. The crystalline material has an input end, an output end and a sensing end. The input end is connected to the light source. The light beam emits into the input end, passes through the crystalline material, and emits out of the output end. An acoustic wave signal is received by the sensing end and changes a structure of the crystalline material. The light analysis module is connected to the output end and receives and analyzes the light beam that passes through the crystalline material.

In an acoustic wave detection probe provided with a light guide section that guides measuring light such that the measuring light is outputted toward a subject and an acoustic wave transducer that detects a photoacoustic wave generated in the subject by the projection of the measuring light, the light guide section includes a homogenizer that flat-tops an energy profile of the measuring light entered from the upstream side of the optical system, a light condensing member that condenses the measuring light transmitted through the homogenizer, and a bundle fiber which includes a plurality of optical fibers and is disposed such that the measuring light transmitted through the light condensing member enters from an entrance end of the bundle fiber.