Category: Probes

The optical tomographic imaging system includes a main body for acquiring an optical tomographic image, an optical probe having a rotary optical fiber for guiding the measuring and returning light, a measuring unit, and a sheath rotatably holding the rotary optical fiber and the measuring unit, a rotary drive unit for rotatably coupling the rotary optical fiber to a stationary optical fiber connected with the main body, an extra length handling mechanism for winding the optical probe into a loop having at least a minimum diameter and an attaching unit removably attaching the optical probe. The extra length handling mechanism ...

Forward-looking ultrasound transducers are positioned at the tip of a transseptal catheter to facilitate transseptal puncture and interventions within the left atrium, pulmonary veins and mitral valve. Catheter devices and systems are guided by forward-looking ultrasound or optical coherence tomography imaging for penetrating from one location within a mammalian patient's body to another location, and/or performing diagnostic or therapeutic interventions. A penetrator, diagnostic, or interventional device (eg. probe, biopsy apparatus, electrode, needle) is positioned at the catheter tip and is advanceable from the catheter to a target location outside of the lumen in which the catheter is positioned ...

We report on a novel scheme for extending the depth of focus (DOF) of ultrathin (125 μm diameter) fiber probes for optical coherence tomography (OCT) using a simple phase mask consisting of graded-index (GRIN) fiber. The technique is compatible with existing all-in-fiber probe fabrication techniques, and our simulations show that it can provide a DOF gain of ∼2 at a modest ∼5  dB reduction of peak sensitivity. In a prototype device using commercially available GRIN fiber, a DOF gain of 1.55 is obtained, validated by beam profiling and OCT imaging.

In an embodiment of the present invention, an OCT probe is configured by including: a thin and long substantially cylindrical sheath whose distal end is closed; an n-reflecting surface body, as an irradiating device, which has n reflecting surfaces (with n being an integer of three or more) and which is provided in a distal end portion of the sheath; a torque transmitting coil, as a rotating device, which is provided along the longitudinal axis of the sheath and which transmits rotational torque for rotating each of the reflection surfaces of the n-reflecting surface body about the longitudinal axis of ...

Advances in optical imaging modalities, such as optical coherence tomography (OCT), enable us to observe tissue microstructure at high resolution and in real time. Currently, core-needle biopsies are guided by external imaging modalities such as ultrasound imaging and x-ray computed tomography (CT) for breast and lung masses, respectively. These image-guided procedures are frequently limited by spatial resolution when using ultrasound imaging, or by temporal resolution (rapid real-time feedback capabilities) when using x-ray CT. One feasible approach is to perform OCT within small gauge needles to optically image tissue microstructure. However, to date, no system or core-needle device has been developed ...

Optical coherence tomography (OCT) has demonstrated its potential as a powerful imaging technology due to its cellular or even subcellular resolution (1-10 μm), which is considered suitable for early detection and diagnosis of cancer. For some clinic applications, for example, intravascular or gastrointestinal investigation, full circumferential scanning (FCS) is highly desired. Early research efforts on FCS such as spinning the entire catheter with build-in cables and fibers were capable of scanning at limited speeds with nonlinear motion due to the long cable rotation. Commercially-available micromotors have also been employed to spin mirrors or prisms to achieve FCS. In recent years ...

We have designed, developed, and evaluated the performance of a multi-degree-of-freedom discretely actuated steerable cannula with shape-memory alloy (SMA) actuators. This will enable us to deliver diagnostic as well as therapeutic devices to the target location through the hollow inner core of the cannula. We propose to use SMAs to generate bending forces due to its small size and high power density. We annealed the SMA wires through a customized training process in an arc shape and mounted them at discrete locations on the outer surface of the cannula to enable joint motion. A pulse-width modulation (PWM)-based control scheme ...

During vitreoretinal surgery, the surgeon manipulates retinal tissue with tool-to-tissue interaction forces below the human sensory threshold. A force sensor (FS) integrated with conventional surgical tools may significantly improve the surgery outcome by providing tactile feedback to the surgeon. We designed and built a surgical tool integrated with a miniature FS with an outer diameter smaller than 1 mm for vitreoretinal surgery based on low-coherence Fabry–Pérot (FP) interferometry. The force sensing elements are located at the tool tip which is in direct contact with tissue during surgery and the FP cavity length is interrogated by a fiber-optic common-path phase-sensitive ...

An image diagnostic system controls a probe to perform rotational and axially-moving scanning within a body cavity and to acquire reflected signals through the probe. Based on the acquired reflected signals, the system forms and outputs tomographic image of the body cavity and biotissue surrounding the body cavity. The system is provided with a detection unit which detects a direction of movement of the probe in the axially-moving scanning and a control unit which controls the rotational speed of the probe in the rotational scanning. The control unit includes a determination unit which determines whether or not the rotational speed ...

A novel prototype of electrothermal chevron-beam actuator based microelectromechanical systems (MEMS) platform has been successfully developed for circumferential scan. Microassembly technology is utilized to construct this platform, which consists of a MEMS chevron-beam type microactuator and a micro pyramidal polygon reflector. The proposed electrothermal microactuators with a two-stage electrothermal cascaded chevron-beam driving mechanism provide displacement amplification, and thus driving a highly reflective micro-pyramidal polygon reflector to rotate a large angle for light beam scan. This MEMS platform is ultra-compact, supports circumferential imaging capability, and is suitable for endoscopic optical coherence tomography (EOCT) application, for example intravascular cancer detection.

Optical measurements of tissue changes during photodynamic and radiation-based cancer treatments help to develop and improve these therapies.  Novel optical technologies can provide detailed microscopic information about tissue structure and physiology in a non-invasive manner, minimizing patient discomfort. This otherwise unobtainable information can help physicians select the best treatments, thus greatly benefiting patients. When used for early disease detection, it results in more effective curative therapies. It also allows inspection of the progress of various therapies to ensure they are working, enabling improvements to be made. We have investigated this last aspect of the benefits of optical methods, showing how ...

We have developed a high precision three axes scanning and positioning system for integration with Multifunctional Image Guided Surgical (MIGS) Platform. The stage integrates three main components: an optical coherence tomography (OCT) probe, laser scalpel and suction cup. The requirements for this stage were to provide scanning area of 400mm2, resolution of less than 10 microns and scanning velocity in the range of 10 - 40 mm/s. The stage was modeled using computer aided design software NX Unigraphics. In addition to the parameters mentioned above, additional boundary conditions for the stage were set as low volume and modularity. Optimized stage ...

A novel prototype of an electrothermal chevron-beam actuator based micro-electromechanical systems (MEMS) platform has been successfully developed for circumferential scan. Microassembly technology is utilized to construct this platform, which consists of a MEMS chevron-beam type microactuator and a micro-reflector. The proposed electrothermal microactuators with a two-stage electrothermal cascaded chevron-beam driving mechanism provide displacement amplification, thus enabling a highly reflective micro-pyramidal polygon reflector to rotate a large angle for light beam scanning. This MEMS platform is ultra-compact, supports circumferential imaging capability and is suitable for endoscopic optical coherence tomography (EOCT) applications, for example, for intravascular cancer detection.

In this paper, we proposed a high lateral resolution common-path Fourier domain optical coherence tomography(OCT) system with the use of a chemically etched single mode fiber. In our experiments, single mode optical fiber for 1310nm was used for preparing the tapered tips. Our system used a conical microlens that was chemically etched by selective chemical etching technique using an etching solution of buffered hydrofluoric acid (BHF). From experimental results, we verified that our proposed optical coherence tomography system could operate as a common-path Fourier domain OCT system and conical tip lens fiber was very useful for a high lateral ...

Needles provide an effective way to reach lesions in soft tissue and are frequently used for diagnosis and treatment. Examples include biopsies, tumor ablation, and brachytherapy. Yet, precise localization of the needle with respect to the target is complicated by motion and deformation of the tissue during insertion. We have developed a prototypical needle with an embedded optical fiber allowing to obtain optical coherence tomography images of the tissue in front of the needle tip. Using the data and particularly the Doppler information it is possible to estimate the motion of the needle tip with respect to the surrounding soft ...