Endoscopic Optical Coherence Tomography Probe Research Articles

Design of an endoscopic OCT probe based on piezoelectric tube with quartered outside electrodes.

Introduction: Optical coherence tomography (OCT) is a pivotal imaging modality in ophthalmology for real-time, in vivo visualization of retinal structures. To enhance the capability and safety of OCT, this study focuses on the development of a micro intraocular OCT probe. The demand for minimal invasiveness and precise imaging drives the need for advanced probe designs that can access tight and sensitive areas, such as the ocular sclera. Methods: A novel OCT probe was engineered using a piezoelectric tube with quartered electrodes to drive Lissajous scanning movements at the end of a single-mode fiber. This design allows the probe to enter the eyeball through a scleral opening. Structural innovation enables the outer diameter of the endoscopic OCT probe to be adjusted from 13G (2.41mm) to 25G (0.51mm), accommodating various imaging field sizes and ensuring compatibility with different scleral incisions. Results: The fabricated micro intraocular OCT probe successfully performed preliminary imaging experiments on in vivo fingers. The Lissajous scanning facilitated comprehensive coverage of the target area, enhancing the imaging capabilities. Discussion: The integration of a piezoelectric tube with quartered outside electrodes into the OCT probe design proved effective for achieving precise control over scanning movements and adaptability to different surgical needs. The design characteristics and practical applications demonstrated the probe's potential in clinical settings.

An imaging analysis and reconstruction method for multiple-micro-electro-mechanical system mirrors-based off-centre scanning optical coherence tomography probe

An endoscopic optical coherence tomography (OCT) probe that can perform full circumferential scans using a circular array of six micro-electro-mechanical system (MEMS) mirrors has been developed. Inside the OCT probe, each of the six MEMS mirrors forms an independent scanning unit; circumferential OCT images are acquired by off-centre scanning and combining the image data from the individual multiple scanning units. Here, an imaging analysis and reconstruction (IAR) method is proposed to construct endoscopic OCT volumetric images from the multiple individual MEMS scanning unit. Imaging procedures of six-MEMS mirrors-based, eight-MEMS mirrors-based and twelve-MEMS mirrors-based OCT probes have been analyzed theoretically. All the data sets are in the Cartesian coordinate system and need to be transformed as fan-shaped images located in the polar coordinate system. The 3-D volume rendering is employed for visualizing the endoscopic data. Typically, this method is used into the image reconstruction of a six-MEMS mirrors-based endoscopic probe. The imaging area is also appropriate for scanning large-scale biological tissue through qualitative and quantitative evaluation. The proposed IAR method using the multiple-MEMS mirrors-based endoscopic off-centre scanning OCT probe has been verified in an experiment of imaging a swine small intestines. This method can be used to analyze the imaging of the multi-MEMS mirrors-based endoscopic OCT probe, which can image the large-scale gastrointestinal tracts in the future.

Side-viewing endoscopic imaging probe for swept source optical coherence tomography

Endoscopic optical coherence tomography (OCT) has many promising applications in the fields of medical research and clinical diagnosis. In this letter, we present a side-viewing endoscopic OCT probe based on a gradient index (GRIN) lens with an air gap. By adjusting the length of the air gap the optical performance of the probe can be flexibly tuned. The quantitative relationships between the optical performance parameters of the probe and its structural parameters are theoretically analyzed by using the ABCD beam transfer matrix theory. The developed probe has a maximum diameter of 1.4 mm and a rigid length of 11 mm. The working distance and the spot size of the probe are measured to be 2.71 mm and 21.24 μm respectively. An endoscopic swept source OCT (SS-OCT) imaging system with an adjustable axial scan rate is built which can flexibly match the rotational scanning speed of the probe. The circumferential OCT images of the tape and the biological tissue are acquired and reconstructed.

Circumferential-scanning endoscopic optical coherence tomography probe based on a circular array of six 2-axis MEMS mirrors.

We present a novel circumferential-scan endoscopic optical coherence tomography (OCT) probe by using a circular array of six electrothermal microelectromechanical (MEMS) mirrors and six C-lenses. The MEMS mirrors have a 0.5 mm × 0.5 mm mirror plate and a chip size of 1.5 mm × 1.3 mm. Each MEMS mirror can scan up to 45° at a voltage of less than 12 V. Six of those mirrors have been successfully packaged to a probe head; full circumferential scans have been demonstrated. Furthermore, each scan unit is composed of a MEMS mirror and a C-lens and the six scan units can be designed with different focal lengths to adapt for lesions with uneven surfaces. Configured with a swept source OCT system, this MEMS array-based circumferential scanning probe has been applied to image a swine's small intestine wrapped on a 20 mm-diameter glass tube. The OCT imaging result shows that this new MEMS endoscopic OCT has promising applications in large tubular organs.

MP17-03 A MINIATURE FORWARD-VIEWING ENDOSCOPIC OPTICAL COHERENCE TOMOGRAPHY PROBE FOR RENAL PELVIC IMAGING

You have accessJournal of UrologyImaging/Radiology: Uroradiology III1 Apr 2015MP17-03 A MINIATURE FORWARD-VIEWING ENDOSCOPIC OPTICAL COHERENCE TOMOGRAPHY PROBE FOR RENAL PELVIC IMAGING Xiaoyong Fu, Dhruti Patel, Hui Zhu, Gregory Maclennan, Yves Wang, Michael Jenkins, and Andrew Rollins Xiaoyong FuXiaoyong Fu More articles by this author , Dhruti PatelDhruti Patel More articles by this author , Hui ZhuHui Zhu More articles by this author , Gregory MaclennanGregory Maclennan More articles by this author , Yves WangYves Wang More articles by this author , Michael JenkinsMichael Jenkins More articles by this author , and Andrew RollinsAndrew Rollins More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.845AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Miniaturized endoscopic optical coherent tomography (EOCT) probe has an important role for non-invasive medical imaging in internal organs with limited dimensions, especially when it can be passed along the working channel of flexible endoscopy. We developed an 0.5mm (1.5F) diameter flexible cone-scanning forward-viewing EOCT probe that can be passed through a flexible ureteroscopy to image renal pelvis. METHODS A simple 0.5mm flexible cone-scanning forward-viewing OCT probe by splicing a 200 μm section of core-less fiber and a 150 μm section of gradient-index (GRIN) fiber to the end of a single mode (SM) fiber. The probe is designed for common-path OCT imaging and the back-reflection of the GRIN fiber/air interface is used as the reference signal. Porcine renal pelvis is imaged ex vivo with the probe to show the layered structure of the renal pelvis. RESULTS EOCT images can clearly reveal all layers of the renal pelvic wall as shown in the Figure. With significantly improved imaging speed, a segment of renal pelvis (1 cm2) can be imaged in a short period of time. CONCLUSIONS With its ability to image all layers of the renal pelvis wall, a miniature forward-viewing EOCT offers the potential to stage urothelial cancers in renal pelvis. This information will be complimentary to the diagnostic information obtained through ureteroscopic biopsy and CT urogram. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e176-e177 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Xiaoyong Fu More articles by this author Dhruti Patel More articles by this author Hui Zhu More articles by this author Gregory Maclennan More articles by this author Yves Wang More articles by this author Michael Jenkins More articles by this author Andrew Rollins More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Imaging endocervical mucus anatomy and dynamics in macaque female reproductive track using optical coherence tomography.

Endocervical mucus acts as an important barrier to block human immunodeficiency virus (HIV) infection and other sexually transmitted diseases (STDs). Disruption of the mucus layer increases the risk of infection for females. An effective method to image the mucus properties can serve as a pre-screening step to risk-stratify the susceptible population. We proposed to use optical coherence tomography (OCT) to quantitatively measure the thickness of endocervical mucus. We used a home-built bench-top OCT system to monitor the dynamic change in mucus thickness of a cultivated sample. We also fabricated a prototype endoscopic OCT probe to demonstrate potential in situ applications. We observed a 200% increase in the endocervical mucus thickness after cultivating in 37 °C phosphate buffered saline solution for 30 minutes. During mucus hydrolysis, we found that mucus layer thickness decreased to about 60% of its original value after applying neuraminidase. Three dimensional volumetric image of intact macaque inner vaginal wall was also acquired. We demonstrated that OCT can quantitatively measure the endocervical mucus thickness and its dynamics in ex vivo experiments. Endoscopic OCT has the potential to resolve fine structures inside macaque female reproductive track (FRT) for in vivo applications.

Tiny endoscopic optical coherence tomography probe driven by a miniaturized hollow ultrasonic motor

We present an endoscopic probe for optical coherence tomography (OCT) equipped with a miniaturized hollow ultrasonic motor that rotates the objective lens and provides an internal channel for the fiber to pass through, enabling 360 deg unobstructed circumferential scanning. This probe has an outer diameter of 1.5 mm, which is ultra-small for motorized probes with an unobstructed view in distal scanning endoscopic OCT. Instead of a mirror or prism, a customized aspheric right-angle lens is utilized, leading to an enlargement of the numerical aperture and thus high transverse resolution. Spectral-domain OCT imaging of bio-tissue and a phantom are demonstrated with resolution of 7.5 μm(axial)×6.6 μm(lateral) and sensitivity of 96 dB.

Miniature endoscopic optical coherence tomography probe employing a two-axis microelectromechanical scanning mirror with through-silicon vias

We present the design and experimental results of a new MEMS-based endoscopic optical coherence tomography (OCT) probe. The uniqueness of this miniature OCT imaging probe is a two-axis MEMS mirror with through-silicon vias (TSVs) for interconnecting. The TSV interconnection enables ultracompact probe design, successfully reducing the probe size to only 2.6 mm in diameter. The MEMS mirror is actuated by an electrothermal actuator that is capable of scanning ± 16° at only 3.6 V DC. Two-dimensional and three-dimensional OCT images of microspheres embedded in PDMS and acute rat brain tissue have been obtained with this miniature probe in a time-domain OCT system.

GRIN lens rod based probe for endoscopic spectral domain optical coherence tomography with fast dynamic focus tracking

In this manuscript, a GRIN (gradient index) lens rod based probe for endoscopic spectral domain optical coherence tomography (OCT) with dynamic focus tracking is presented. Current endoscopic OCT systems have a fixed focal plane or working distance. In contrast, the focus of this endoscopic OCT probe can dynamically be adjusted at a high speed (500 mm/s) without changing reference arm length to obtain high quality OCT images for contact or non-contact tissue applications, or for areas of difficult access for probes. The dynamic focusing range of the probe can be from 0 to 7.5 mm without moving the probe itself. The imaging depth is 2.8 mm and the lateral scanning range is up to 2.7 mm or 4.5 mm (determined by the diameter of different GRIN lens rods). Three dimensional imaging can be performed using this system over an area of tissue corresponding to the GRIN lens surface. The experimental results demonstrate that this GRIN lens rod based OCT system can perform a high quality non-contact in vivo imaging. This rigid OCT probe is solid and can be adapted to safely access internal organs, to perform front or side view imaging with an imaging speed of 8 frames per second, with all moving parts proximal to the GRIN lens, and has great potential for use in extremely compact OCT endoscopes for in vivo imaging in both biological research and clinical applications.