Working Distance Research Articles

A miniature capsule endoscope based on spiral antenna with wireless sensing capabilities

Abstract In this paper, a capsule endoscopy system with a sensing function is proposed for medical devices. A single-arm spiral antenna is designed for data transmission and is combined with the voltage controlled oscillator to achieve sensing capabilities. The designed antenna operates at a 900 MHz industrial scientific medical band. By establishing a three-layer cylindrical model of the stomach, it was concluded that the antenna in the stomach has a high peak gain of −1.1 dBi. Additionally, the antenna achieved a −10 dB impedance bandwidth of 5%. The capsule endoscopy was experimentally measured in both actual stomach and simulated environments. The maximum working distance of the capsule endoscope was measured to be 6.8 m. Additionally, the proposed capsule endoscope was tested for its sensing function using solutions with different dielectric constants. Finally, it was confirmed through link analysis that it has good communication capabilities. The results and analysis confirm that the proposed capsule endoscope can be used for examining gastric diseases.

Vapor Channel Oscillations in Laser Lithotripsy.

Laser-based endoscopic procedures present special challenges to deliver energy for ablation or coagulation of target tissues. When optical fiber-target quasi-contact (< 0.5 mm distance) cannot be maintained or is undesirable, the creation of intervening vapor bubbles and channels provide for the necessary transmission of laser energy to the target. This work investigates the characteristics and the dynamics of vapor channels that directly affect ablation efficiency and ablation rate and are known to effect stone movement, all of which impact procedure efficiency and safety. A simplified, experimental model for thulium fiber laser (1940 nm) lithotripsy consists of a water-filled cuvette and a vertically oriented laser fiber (200 μm core diameter) with its tip at 9 mm for "quasi-free" bubble generation and at vapor channel working distances 1-5 mm from and centered on the transparent cuvette bottom simulating a target's surface. Laser power transmission is recorded and synchronized with video frames from a high-speed camera (24,260 frames per second) to capture the induced vapor channels' and bubbles' development. Laser-induced channel transmission from 0% to 100% for 1, 2, and 3 mm fiber-target distances undergoes oscillations with average periods of 0.32, 0.64, and 1.0 ms, respectively, for 500 W laser output power. For fixed fiber-target distances of 0.5, 1, and 2 mm, the variation of these average oscillation frequencies across laser powers from 500 to 1000 W is much smaller, not exceeding 14%. For fiber-target distances in the range of 1-5 mm, the fraction of the 500 W laser's total pulse energy delivered to the target for 1, 2, and 3 ms pulses linearly decreases from 0.78 to less than 0.2. The channel and bubble dynamics begin with a spherical seed bubble expansion centered on the distal fiber tip that evolves into a pear shape whose surface exhibits periodic irregularities attributable to laser beam interruption by water droplets within the developing bubble. The study of laser-induced channel oscillations provides quantitative information relating fiber-target distance to channel oscillation frequency and energy transmission onto a target. These oscillations directly effect ablation efficiency and ablation rates that are important parameters for the optimization of a procedure's safety and duration. Insights that may lead to further reduction in retropulsion are also presented. Lasers Surg. Med. 00:00-00, 2024. © 2024 Wiley Periodicals LLC.

Measurement of circular intensity differential scattering (CIDS) from single optically trapped biological particles

The circular intensity differential scattering (CIDS), which is the normalized Mueller matrix element -S14/S11, has been measured from single biological particles as a function of scattering angle. CIDS is valuable for its potential in detecting chiral particles that may include the helical structures of DNA or RNA molecules in biological samples, and as such is a potential method for detecting biological particles. Optical trapping is employed to levitate single particles within a custom-designed elliptical reflector for CIDS measurements. The advantage of optical levitation in light-scattering measurements is that single particles can be suspended in air with sufficient working distance to prevent interference from the suspending apparatus. To measure the phase function, the reflector is used to collect the angle-dependent scattering signals. We demonstrated that we can obtain two-dimensional angular optical scattering (TAOS) patterns that cover a wide angular range from single levitated particles. These TAOS patterns are generated using 532 nm illumination of left-handed and right-handed circular polarizations and recorded from trapped single particles (silica, English Oak, Ragweed, Mulberry, Glycine, and l-Aspartic acid).

Critical Impact of Working Distance on OCT Imaging: Correction of Optical Distortion and Its Effects on Measuring Retinal Curvature.

To assess the impact of working distance (WD) on optical distortion in optical coherence tomography (OCT) imaging and to evaluate the effectiveness of optical distortion correction in achieving consistent retinal Bruch's membrane (BM) layer curvature, regardless of variations in WD. Ten subjects underwent OCT imaging with four serial macular volume scans, each employing distinct WD settings adjusted by balancing the sample and reference arm of the OCT interferometer (eye length settings changed). Either of two types of 30° standard objectives (SOs) was used. A ray tracing model was used to correct optical distortion, and BM layer curvature (represented as the second derivative of the curve) was measured. Linear mixed effects (LME) modeling was used to analyze factors associated with BM layer curvature, both before and after distortion correction. WD exhibited significant associations with axial length (β = -1.35, P < 0.001), SO type (P < 0.001), and eye length settings (P < 0.001). After optical distortion correction, the mean ± SD BM layer curvature significantly increased from 16.80 ± 10.08µm-1 to 49.31 ± 7.50µm-1 (P < 0.001). The LME model showed a significant positive association between BM layer curvature and WD (β = 1.94, P < 0.001). After distortion correction, the percentage change in BM layer curvature due to a 1-mm WD alteration decreased from 9.75% to 0.25%. Correcting optical distortion in OCT imaging significantly mitigates the influence of WD on BM layer curvature, enabling a more accurate analysis of posterior eye morphology, especially when variations in WD are unavoidable.

Ultracompact all-fiber self-transceiving ultrasonic probe with an enhanced working distance.

All-optical ultrasonic probes exhibit notable benefits in ultrasonic detection and imaging. Typically, two separate optical fibers are used for excitation and detection, yet limited research has explored the integration of both functionalities within a single fiber. In this Letter, to our knowledge, a new method for fabricating an all-fiber self-transceiving ultrasonic probe is proposed with a lateral dimension of less than 500 µm. Double cladding fiber (DCF) is spliced with a short segment of thin-diameter single-mode fiber (TDSMF), which is then embedded into a fiber bubble to form a Fabry-Perot cavity, and the bubble surface is coated with a composite material layer. The pulsed laser propagates through the inner cladding of DCF and leaks from the splicing point of DCF-TDSMF, inducing the material excitation for efficient ultrasound generation. The core-guided detection laser is directed to the TDSMF end, entering the bubble microcavity and inducing an optical interference for weak echo detection. The emitting functionality produces an ultrasound with a -6 dB bandwidth of 17.5 MHz and a peak frequency of 6.29 MHz, which is well-matched with the fiber microcavity's response frequency of 3.29 MHz. Through self-transceiving experiments, low-noise pulse-echo signals are captured at varying working distances of up to 3.78 cm. The proposed probe exhibits great potential in biomedical and industrial fields due to its all-fiber miniaturization and enhanced-distance detection capability.

Cold atmospheric plasma activated media selectively affects human head and neck cancer cell lines.

Cold atmospheric plasma (CAP) is a novel approach for cancer treatment. It can be used to treat liquids-plasma-activated media (PAM)-which are then transferred to the target as an exogenous source of reactive oxygen and nitrogen species (RONS). The present study aimed at chemically characterizing different PAM and assessing their invitro selectivity against head and neck cancer cells (HNC). PAM were obtained by exposing 2 and 5 mL of cell culture medium to CAP for 5, 10 and 20 min at a 6 mm working distance. Anions kinetics was evaluated by ion chromatography. Cell proliferation inhibition, apoptosis occurrence, and cell cycle modifications were assessed by MTS and flow cytometry, on human epidermal keratinocyte (HaCaT) and HNC cell lines HSC3, HSC4 and A253. The 2 mL conditions showed a significant reduction in cell proliferation whereas for the 5 mL the effect was milder, but the time-dependence was more evident. HaCaT were unaffected by the 5 mL PAM, indicating a selectivity for cancer cells. The media chemical composition modified by CAP exposure influenced cell proliferation by modulating cell cycle and inducing apoptosis in cancer cells, without affecting normal cells.

A versatile 5-axis melt electrowriting platform for unprecedented design freedom of 3D fibrous scaffolds

Melt electrowriting (MEW) is an electrohydrodynamic additive manufacturing technology for the fabrication of precise microfiber scaffold architectures but is so far restricted to printing onto simple collector geometries and, therefore, constrained in design freedom. This is due to current limitations in print head designs, kinematic systems, and software to generate motion commands. We address these aspects by upgrading a low-cost 5-axis kinematic system and complete it with a custom-designed print head and a collector fabrication workflow to enable collision-free MEW onto arbitrarily shaped multicurvature 3D geometries. A universal graphical approach enables generation of Gcodes customized to the 5-axis MEW requirements. The print head is validated by producing polycaprolactone fibers with diameters ranging from 5.6 ± 1.7 µm to 50.7 ± 5.5 µm and by writing both linear and non-linear fiber patterns onto collectors featuring concave and convex surfaces. Stable printing conditions are achieved by continuously reorienting the print head and collector surface perpendicular to each other at a constant working distance. Ultimately, we demonstrate the system’s potential in shaping anatomically relevant scaffold geometries by stacking microfibers onto collectors resembling a trileaflet valve and a bifurcating vessel. This multi-axis MEW platform unlocks exciting avenues towards unprecedented design freedom for MEW scaffolds.

Development of an in-situ real-time laser targeting algorithm for a 3D LiDAR-integrated galvanometric laser scanner system

A Galvanometric laser scanner utilizes mirrors attached to dual galvanometers to direct laser beams. GLS systems are widely employed across various industrial sectors due to their compact size, high resolution, and high positional repeatability. Extensive research has been conducted to calibrate these systems to steer lasers to desired positions accurately. However, much of this research has traditionally focused on fixed working distances, which does not align well with the portable capabilities that GLS systems offer in non-destructive evaluation fields. This study explores an algorithm that enables real-time laser targeting using a 3D LiDAR camera integrated into a GLS system. The research involved developing and calculating a projection matrix that projects 3D camera coordinates into 2D bit coordinates input to each galvanometer, based on linear assumptions. To address the non-linear errors that emerge from the linear assumption process, compensation was applied through 3rd-order regression and Artificial neural networks. As a result, the algorithm facilitated highly accurate laser targeting within a range of 0.5 m to 2.5 m based on coordinates acquired by the LiDAR camera.

Improving the working distance for near-field lithography with supercell photonic crystal

Near-field lithography technology plays a vital role in chip manufacturing. However, near-field lithography devices with acceptable working distance (WD) have become a long-term pursuit for researchers. Here, a one-dimensional supercell photonic crystal (SPC) is proposed for near-field lithography. The simulation results show that the PCs could provide an air WD of over 100 nm in interference lithography and produce patterns with a resolution reach ∼67 nm (∼λ/6). The analyses indicate that using SPCs in interference lithography can make it more suitable for practical manufacturing. Furthermore, this type of PC can also be used in direct writing lithography. The simulation results show that the direct writing lithography could be realized with a WD of 100 nm, and the full width at half maximum of the focal spot is ∼137 nm. The principle presents a new method for controlling the evanescent waves, and the method would greatly promote the development and application of near field lithography.

Photoangiolysis with the 445-nm Blue Laser and the Potassium-Titanyl-Phosphate Laser: A Comparison.

Photoangiolytic lasers have yielded significant innovation in laryngeal surgery in the last 25 years. After the discontinuation of the potassium titanyl phosphate (KTP) laser, a novel 445-nm blue laser was developed. The optimal balance between a laser's desired tissue effects and collateral tissue damage is a major determinant of laser selection in microlaryngeal surgery. The shell-less incubation system for the chick chorioallantoic membrane (CAM) simulates the microvasculature of the human vocal fold and is useful for testing effects of laser settings and in simulated surgery. The aim of this study is to compare the tissue effects of the KTP and blue lasers using the shell-less CAM model. The shell-less incubation system contains: polymethylpentene film (used as a culture vessel), calcium lactate and distilled water supplementations. By using this system, the chick chorioallantoic membrane (CAM) can be fully exposed with a good field for surgery simulation. The effects of the 2 lasers (532 nm KTP and 445 nm blue) were quantified at clinically relevant energy settings and laser distances from target. Measures included imaging real-time vascular reactions in the CAM model, post-procedure histologic analysis of CAM tissue and temperature changes. Vessel coagulation and rupture rates were less common with the blue laser compared with the KTP laser. Histologic analysis demonstrated less tissue disruption with the blue laser. Temperature changes were less with the blue laser. In this CAM model with specific conditions, the blue laser reveals less tissue damage than the KTP laser. Suitable working distance and power setting of the laser are necessary for desired tissue effects.Level of Evidence: Level 3.

Surface Tuning of Transparent Electrodes with Atmospheric Pressure Plasma for Third Generation Photovoltaics

Transparent semiconductor thin films such as indium tin oxide (ITO) and fluorine-doped tin oxide (FTO) are commonly used in optoelectronic devices due to their favorable properties such as high conductivity and transparency and suitable work function [1]. Their use ranges from light-emitting diodes through flat panel displays up to solar cells. In this context, surface stoichiometry plays a crucial role in influencing the final properties of the final device. Therefore, efficient surface treatment has been a topic in research for years, covering a wide range of approaches from wet and dry treatments. Among these possibilities, plasma treatment remains today the most effective. In several studies [2, 3], atmospheric pressure plasma shown an increase of surface energy, decrease the contamination while enhancing the work function of both ITO and FTO. Low temperature, fast processing times, and no special requirements for working gas are the main advantages of this approach.In this study, the authors compare the effects of cold (<100°C) atmospheric pressure plasma on ITO and FTO after air and nitrogen treatment to provide deeper insight into the interaction of discharge with semiconductive materials during treatment. A coplanar dielectric barrier discharge has been used for the surface modification (more information available in [4]). For this configuration both electrodes lay in one plane, and the discharge occurs on the top of the barrier. Chemical changes in the surface were also evaluated as a function of plasma parameters without any pre-treatment of the substrates. For both studied materials, similar trends were observed at fast treatment times (<60s of plasma exposure). The plasma treatment resulted in a decrease of water contact angle from the initial 90° for ITO to 10° after 30 seconds of exposure. For FTO, the initial angle 60° was lowered to 10° after just 5 seconds of exposure, and complete hydrophilicity was obtained after 30 seconds of plasma treatment. An interesting trend in oxygen concentration measured by XPS was observed for ITO but not FTO samples. From a physical point of view, the interaction with the conductive sample affects the orientation of filaments during the surface modification. Additionally, the results suggest that for small working distances, the physical regime can vary from coplanar to volume discharge as shown in Figure 1. All changes were observed with ICCD imaging (Pi-Max 4, Princeton Instruments). Regarding the physical changes over the surface, the plasma treatment resulted in decreased roughness with no significant effect on conductivity.In conclusion, the results obtained in this study can be utilized in the manufacturing process of microelectronic devices and provide a deeper insight into how the treatment process influences discharge parameters.[1] Armstrong et al. https://doi.org/10.1016/j.tsf.2003.08.067[2] Šimor et al. https://doi.org/10.1063/1.1513185[3] Donley et al. https://doi.org/10.1021/la011101t[3] Chaney et al. https://doi.org/10.1016/S0169-4332(03)00617-2 Figure 1

Practical design of the focusing system for transmission and reflection targets in X-ray sources

The incident beam quality at the target determines the resolution and intensity of micro-focus X-ray sources, which depends greatly on the focusing system and the target. To meet different spatial layouts of the focusing system with transmission and reflection targets, three-dimension (3-D) modelling of the focusing system was built with Monte Carlo simulation and coordinate transforming method in this paper. In the proposed approach, the focusing system was first optimized by a 2-D model to achieve a fine beam spot with high effective current at the optimum working distance for the transmission and reflection targets. Then, 3-D practical model of the focusing system was achieved by tracing N electrons from the electron gun in three directions using the 5-order Runge-Kutta method. Finally, examples of the focusing system for 90 keV and 30 keV X-ray sources were given to get the energy distributions at transmission and reflection targets. Results show that resolutions of 4 μm and 500 nm have been achieved for 90 keV X-ray source with the transmission target and 30 keV X-ray source with the reflection target respectively. Compared with the experimental results, 2-D modelling of the focusing system is also applicable for X-ray source with the transmission target while 3-D modelling of the focusing system is essential for X-ray source with the reflection target. In addition, the 3-D electron beam model will simplify the design of the real apertures, liner tubes, beam blankers etc.

Design of a catadioptric mid-wave infrared telecentric microscope with high numerical aperture and long working distance

Infrared microscopy is widely used in the field of thermal analysis. This paper proposes a design method for a catadioptric mid-wave infrared telecentric microscope system that solves the problem of traditional microscopy systems being unable to simultaneously meet high numerical aperture, long working distance and large magnification requirements. The system is composed of a microscope objective and a tubelens. The objective uses an improved Schwarzschild structure and is connected to the tubelens through an externally located pupil. The system works in the wavelength range of 3.7 μm–4.8 μm, achieves a 0.82 numerical aperture, a 15.5 mm working distance, an 8× magnification and a 2.75 μm object-side resolution. The image size of the detector is 17um, and the MTF of the microscope system at the detector cutoff frequency is greater than 0.2, which is close to the diffraction limit. Finally, tolerance analysis and athermal analysis are conducted on the system, and the results indicate that the system possesses good manufacturability and thermal stability.

Design and fabrication of a large-aperture electrowetting liquid zoom system

In this paper, a continuous zoom system based on large-aperture electrowetting liquid lenses is designed and fabricated. The inner diameter of the electrowetting lens is up to 20 mm, which can tune stably from a focal length of −328.49mm to −∞ with applied voltages of 0 to 115 V. The zoom system mainly consists of two large-aperture electrowetting liquid lenses and a glass lens, getting continuous zoom images by adjusting the voltages applied to the two liquid lenses without any mechanical movement, ensuring a more compact structure than conventional zoom systems. The theoretical formulas of the zoom ratio and image plane stability condition for this optical system are systematically derived based on the matrix optics, laying the foundation for guiding system regulation and finding methods to improve zoom ratio, and corresponding influence factors on the zoom ratio are verified by experiments. The system zoom ratio can reach 1.52 at a fixed working distance, close to the theoretical derivation result. The system is expected to be used for imaging in a variety of scenarios, such as special photography, dynamic measurement, etc.

Microlens arrays for multichannel laser-to-waveguide coupling

An optical multichannel coupling system for coupling laser arrays to waveguide arrays is developed. Based on a microlens array, the system enables coupling of nine individual optical channels, with one aspheric microlens per channel at a lateral channel pitch of 100 µm. The design process criteria for the proposed microlenses, with 97 µm diameter and working distances from laser to lens and lens to waveguide of 150 µm and 275 µm, respectively, are described. The microlens array is fabricated on a 4mm×2mm×0.41mm fused silica chip and contains an orthogonal grid with 32×16 microlenses, of which a row of nine adjacent microlenses is used for coupling. Uniform coupling over all channels can be achieved, as well as specific coupling for each channel individually with less than −13.5dB crosstalk. The coupling system is designed for optical neural stimulators.

Comparative Anatomy of the Contralateral Transmaxillary Approach Alone and With Ipsilateral Transpterygoid Extension: Quantitative Insights on Surgical Exposure and Maneuverability in the Petroclival Region.

Beyond qualitative evidence legitimizing endoscopic corridors through contralateral transmaxillary (CTM) and endonasal ipsilateral transpterygoid (ITP) corridors to the petrous apex and petroclival region, surgical feasibility by direct quantitative comparative anatomy is sparse. Our cadaveric study addresses this by performing the CTM approach followed by ITP extension to quantify the extent of petrous apex resection, instrument maneuverability, and working distance to petrous apex. Anatomic dissections were performed bilaterally on 5 latex-injected human cadaveric heads (10 petrous bones). After CTM dissections were quantified, the ITP approach was added enlarging initial exposure. Differences were measured with statistical significance when P values are < .05. The mean petrosectomy volume was 0.958 cm3 with CTM and 1.987 cm3 with CTM + ITP, corresponding to 14.53% and 30.52% petrous apex resection, respectively. Craniocaudal instrument mobility was more limited in the lateral extent of dissection compared with the midline for both CTM (8.062° vs 14.416°) and CTM + ITP (5.4° vs 14.4°). The CTM approach achieved the lateral-most dissection at the body of the petrous apex (15.936 mm), with lateralization more limited in the superior petroclival region (9.628 mm) and the inferior petroclival region (8.508 mm). Angle of surgical maneuverability increased superiorly vs inferiorly in the CTM approach (mean 12.596° vs 8.336°, respectively). The CTM approach offered the shortest mean working distance (88.624 mm) to the petroclival region compared with the bi-nares approach (100.5 mm). CTM + ITP achieved greater lateralization in the superior (21.237 mm) and inferior (22.087 mm) aspects of the petroclival region compared with the CTM approach. Operative considerations are discussed in accessing target neurovascular structures through the uniquely shaped corridors formed by the CTM or combined CTM + ITP. Allowing mobilization of the internal carotid artery laterally and eustachian tube inferiorly, addition of the ITP allowed for larger petrosectomy than CTM alone, especially in the inferior and lateral aspects of the petrous bone.

Non-mydriatic ultra-widefield diffraction-limited retinal imaging.

We demonstrate a new non-mydriatic ultra-widefield optical coherence tomography retinal imaging system, designed with custom optics to improve the imaging field of view, lateral resolution, and patient comfort. The key motivation is to address the challenge with conventional systems that require pupillary dilation, adding time, expense, discomfort, and medical risk to the examination of the retina. Our system provides an ultrawide 100° field of view (beam scanning angle at the scanning pivot point) and maintains a lateral resolution of 20 µm on the center. It also allows a generous working distance of 16 mm, 2-3 times longer than existing ultra-widefield OCT imaging systems. This advanced system was able to avoid iris vignetting artifacts without pharmacological dilation and ensure diffraction-limited ultra-widefield imaging under a generalized eye model. This enables a comprehensive evaluation of retina diseases, especially those affecting the peripheral regions.

Manufacturability-based optical design optimization for advanced Kirkpatrick-Baez X-ray focusing mirrors.

The advanced Kirkpatrick-Baez (AKB) mirror setup is an effective and compelling solution to provide stable X-ray nano-focusing for synchrotron radiation or free-electron laser beamlines. We propose an AKB mirror design optimization approach to mitigate the difficulties associated with mirror fabrication by minimizing the total slope ranges of the four curved mirrors while achieving the expected focusing performance. In the optimization, we have considered geometry constraints to ensure the beam acceptance with the required clear aperture, the diffraction-limited focal size with the adequate numerical aperture, and the desired mirror gaps for adjustment and the necessary working distance for the sample stage. Additionally, practical constraints linked to mirror metrology and fabrication, such as mirror length limits and curvature uncertainty in measurement, are taken into account. Furthermore, progressive objective optimization eliminates the need for any initial guess, fully automating the AKB optimization process. This approach facilitates the development of an elegant Wolter-I or Wolter-III type AKB design solution that satisfies these multiple constraints. In cases where constraints cannot be simultaneously satisfied, the optimization results provide valuable insights into areas where trade-offs need to be considered. Simulations with ray tracing and wavefront propagation validate the optimized AKB design showing high tolerance to the beam incident angle.

Comparison of endoscopic multiport approaches to the petrous apex: contralateral transmaxillary versus contralateral medial transorbital corridor.

Accessing the petrous apex (PA) via an endoscopic endonasal approach (EEA) is challenging due to its posterior and lateral anatomical relationship with the paraclival carotid artery. Typically, the EEA requires the mobilization or compression of the vessel and the use of angled-lens endoscopes and instruments. A sublabial contralateral transmaxillary (CTM) corridor has been used to overcome these challenges. Still, it requires extensive osteo-meatal disruption and drilling of the medial pterygoid process, which risks the vidian nerve and increases nasal morbidity. Furthermore, the CTM corridor positions the endoscope in the same horizontal plane as the instruments passing through the nostrils, leading to fencing. The authors propose a novel minimally invasive route to the PA, the precaruncular contralateral medial transorbital (cMTO) corridor, to address these issues. This anatomical study compares the EEA+CTM and EEA+cMTO corridors in accessing the PA. The authors dissected 14 fresh, preinjected cadaveric specimens (28 sides) using neuronavigation to complete EEA, cMTO, and CTM on each side. In addition to qualitative analysis, they measured and compared the working distance between the entry point (nose, orbit, maxilla) and the petrosal process of the sphenoid bone (PPSB), superomedial PA, and foramen lacerum (FL); angle of attack (AoA); area of surgical freedom; endoscope-instrument fencing angle; and visual angle for each approach. The cMTO corridor provided the shortest working distance to the petroclival region (PA = 67.4 ± 4.47 mm, PPSB = 67.57 ± 4.33 mm, and FL = 66.30 ± 4.77 mm) compared to the CTM (PA = 75.85 ± 3.63 mm, PPSB = 76 ± 3.96 mm, and FL = 74.52 ± 4.26 mm) and to the EEA (PA = 85.16 ± 3.16 mm, PPSB = 84.55 ± 3.02 mm, and FL = 83.42 ± 3.21 mm, p < 0.001). Both CTM and cMTO corridors had a similar visual angle to the PA (20.72° ± 2.16° and 21.63° ± 1.84°, respectively), offering a similar but significantly better visualization than EEA alone (44.71° ± 3.24°, p < 0.001). The cMTO corridor provided better instrument maneuverability than the CTM, as evidenced by a significantly greater fencing angle (30.9° ± 4.9°) than with the CTM (21.7° ± 4.02°, p < 0.001). The vertical AoAs for the EEA, cMTO, and CTM corridors were 9.79° ± 1.75°, 10.65° ± 0.82°, and 9.82° ± 1.43°, respectively (p = 0.009), whereas in the horizontal plane, these were 9.29° ± 1.51°, 9.10° ± 0.73°, and 10.49° ± 1.43° (p < 0.001), respectively. Both the CTM and cMTO corridors offered similar areas of surgical freedom (678.06 ± 99.5 mm2 and 673.59 ± 104.8 mm2, p = 0.986), but they were more significant than that provided by the EEA 487.29 ± 112.9 mm2 (p < 0.001). The EEA+cMTO multiport technique may be a better alternative than the EEA+CTM multiport approach for targeting the petroclival region. However, clinical validation is required to confirm these laboratory findings.

Axially swept open-top light-sheet microscopy for densely labeled clinical specimens.

Open-top light-sheet (OTLS) microscopy offers rapid 3D imaging of large optically cleared specimens. This enables nondestructive 3D pathology, which provides key advantages over conventional slide-based histology including comprehensive sampling without tissue sectioning/destruction and visualization of diagnostically important 3D structures. With 3D pathology, clinical specimens are often labeled with small-molecule stains that broadly target nucleic acids and proteins, mimicking conventional hematoxylin and eosin (H&E) dyes. Tight optical sectioning helps to minimize out-of-focus fluorescence for high-contrast imaging in these densely labeled tissues but has been challenging to achieve in OTLS systems due to trade-offs between optical sectioning and field of view. Here we present an OTLS microscope with voice-coil-based axial sweeping to circumvent this trade-off, achieving 2 µm axial resolution over a 750 × 375 µm field of view. We implement our design in a non-orthogonal dual-objective (NODO) architecture, which enables a 10-mm working distance with minimal sensitivity to refractive index mismatches, for high-contrast 3D imaging of clinical specimens.