Deep learning-driven macroscopic AI segmentation model for brain tumor detection via digital pathology: Foundations for terahertz imaging-based AI diagnostics.

We used deep learning methods to develop an AI model capable of autonomously delineating cancerous regions in digital pathology images (H&E-stained images). By using a transgenic brain tumor model derived from the TS13-64 brain tumor cell line, we digitized a total of 187 H&E-stained images and annotated the cancerous regions in these images to compile a dataset. A deep learning approach was executed through DEEP:PHI, which abstracts Python coding complexities, thereby simplifying the execution of AI training protocols for users.

Extensive Q-factor tuning for leaky modes with minimal frequency variation in asymmetric slab grating structures.

We investigated an asymmetric slab grating structure to achieve significant tuning of the quality (Q) factor for a leaky mode while minimizing frequency variation. This structure comprises two identical gratings placed on the top and bottom of a slab waveguide, with one grating laterally shifted to introduce asymmetry. Simulations demonstrate that lateral shifting of one grating induces extensive changes in the Q-factor with minimal frequency variation, particularly near the band-flip filling fraction because the band-flip filling fraction remains unaffected by the shifting.

C5α secreted by tumor mesenchymal stem-like cells mediates resistance to 5-aminolevulinic acid-based photodynamic therapy against glioblastoma tumorspheres.

Purpose: Advancements in photodynamic diagnosis (PDD) and photodynamic therapy (PDT) as a standard care in cancer therapy have been limited. This study is aimed to investigate the clinical availability of 5-aminolevulinic acid (5-ALA)-based PDD and PDT in glioblastoma (GBM) patient-derived tumorspheres (TSs) and mouse orthotopic xenograft model.

Methods: PDT was performed using a 635 nm light-emitting diode (LED).

Anodically Induced Chemical Etching of GaAs Wafers for a GaAs Nanowire-Based Flexible Terahertz Wave Emitter.

A generic top-down approach for the preparation of extended arrays of high-aspect ratio GaAs nanowires (NWs) with different crystallographic orientations (i.e., [100] or [111]) and morphologies (i.

Measuring water contents in animal organ tissues using terahertz spectroscopic imaging.

We investigated the water contents in several organ tissues such as the liver, spleen, kidney, and brain tissue of rats using the terahertz spectroscopic imaging technique. The water contents of the tissues were determined by using a simple equation containing the absorption coefficients of fresh and lyophilized tissues and water. We compared the measured water contents with the difference in mass of tissues before and after lyophilization.

Improvement of Terahertz Wave Radiation for InAs Nanowires by Simple Dipping into Tap Water.

We report improvement of terahertz (THz) wave radiation for Si-based catalyst-free InAs nanowires (NWs) by simple dipping into tap water (DTW). In addition, the possibility of using InAs NWs as a cost-effective method for biomedical applications is discussed by comparison to bulk InAs. The peak-to-peak current signals (PPCSs) of InAs NWs measured from THz time-domain spectroscopy increased with increasing NW height.

Terahertz reflectometry imaging for low and high grade gliomas.

Gross total resection (GTR) of glioma is critical for improving the survival rate of glioma patients. One of the greatest challenges for achieving GTR is the difficulty in discriminating low grade tumor or peritumor regions that have an intact blood brain barrier (BBB) from normal brain tissues and delineating glioma margins during surgery. Here we present a highly sensitive, label-free terahertz reflectometry imaging (TRI) that overcomes current key limitations for intraoperative detection of World Health Organization (WHO) grade II (low grade), and grade III and IV (high grade) gliomas.

Terahertz otoscope and potential for diagnosing otitis media.

We designed and fabricated a novel terahertz (THz) otoscope to help physicians to diagnose otitis media (OM) with both THz diagnostics and conventional optical diagnostics. We verified the potential of this tool for diagnosing OM using mouse skin tissue and a human tympanic membrane samples prior to clinical application.

Feasibility of terahertz reflectometry for discrimination of human early gastric cancers.

We have investigated the feasibility of THz time-domain reflectometry for the discrimination of human early gastric cancer (EGC) from the normal gastric region. Eight fresh EGC tissues, which were resected by endoscopic submucosal dissection, were studied. Of them, six lesions were well discriminated on THz images and the regions well correlated with tumor regions on pathologically mapped images.

Terahertz spectroscopic imaging and properties of gastrointestinal tract in a rat model.

We have investigated basic properties of normal gastrointestinal (GI) tract tissues, including glandular stomach (GS), fore stomach (FS), large intestine (LI), small intestine (SI), and esophagus (ESO), from a rat model using terahertz (THz) reflection imaging and spectroscopy. The THz images collected from stratified squamous epithelia (SSE) of FS and ESO show a lower peak-to-peak value compared to those from columnar epithelia (CE) of GS, LI, or SI because the SSE contains less water than CE. The refractive index and absorption coefficient of FS were less than those of GS or LI, both having values similar to those of water.

Study of freshly excised brain tissues using terahertz imaging.

We demonstrated that tumors in freshly excised whole brain tissue could be differentiated clearly from normal brain tissue using a reflection-type terahertz (THz) imaging system. THz binary images of brain tissues with tumors indicated that the tumor boundaries in the THz images corresponded well to those in visible images. Grey and white-matter regions were distinguishable owing to the different distribution of myelin in the brain tissue.

Improvement of THz coupling using a tapered parallel-plate waveguide.

This paper reports an experimental and simulation study of a tapered parallel-plate waveguide (TPPWG) to improve THz coupling to the plate separation gap. The flat- and round-type TPPWG without any silicon lens is compared to the parallel-plate waveguide (PPWG) with a plano-cylindrical silicon lens. The spectrum amplitudes of the input-side TPPWG and the input- and output-side TPPWG both having a 3 degrees slop angle increased about 56% and 103% at 1 THz when compared to that of the PPWG.

A miniaturized fiber-coupled terahertz endoscope system.

In this study, we have designed, fabricated, and characterized a miniaturized optical fiber-coupled terahertz (THz) endoscope system. The endoscopic system utilized a photoconductive generator and detector driven by a mode-locked Ti:sapphire laser. In reflection mode, the endoscope showed a high signal-to-noise ratio and a wide frequency spectrum similar to the conventional THz time-domain spectroscopic system.

Enhancement of the detection of THz Sommerfeld wave using a conical wire waveguide.

In this study, the coupling properties of a conical copper wire waveguide were investigated in the terahertz (THz) frequency range using theoretical simulations and experiments. Because a conical wire tip has a smaller tip diameter than a cylindrical wire tip, it has a greater THz field density than a cylindrical wire tip. The measured THz pulse increased 4.