Potential Imaging Capability of Optical Coherence Tomography as Dental Optical Probe: A Mini-Review

Optical coherence tomography (OCT) has been emerging in the dental field as an alternative diagnostic imaging for “optical probes” owing to its micro-meter resolution and non-invasiveness. This review aims to answer the following question: what is the imaging capability of OCT to visualize the subgingival area? Online searches were performed on PubMed and SPIE digital library databases, followed by a manual screening of references listed in relevant studies. The feasibility and imaging performance of OCT to visualize the subgingival area, including the periodontal, peri-implant, and crown margins, are discussed. All of the literature reviewed in this study demonstrated that OCT has the ability to visualize periodontal, including hard and soft tissues, and peri-implant conditions with high resolution. Gingival sulcus depth, periodontal pocket, and calculus deposition can also be depicted. However, clinical evidence that support the imaging capability of OCT as a dental optical probe to visualize subgingival area is lacking. Limited availability, portability, and usability of OCT for clinical experiments in dentistry, particularly for the subgingival area, might be contributed to its limitations. Hence, further development of handheld OCT systems and controlled clinical trials are needed to confirm the imaging capability of OCT reported in this review.

Virtual Bronchoscopy as the Guide for Fiberoptic Bronchoscopy in Evaluating Tracheobronchial Disorders in the Bronchogenic Carcinoma

Fiberoptic bronchoscopy (FOB) is one of the important modalities in helping to uphold the diagnosis and stadium of bronchogenic carcinoma. However, FOB has some limitations, namely invasive, time-consuming, requiring sedation, intolerable in patients who are critically ill, and difficult to evaluate distal airway side of severe stenosis. To identify the imaging capability of virtual bronchoscopy (VB) examinations in evaluating abnormalities in the tracheobronchial in bronchogenic carcinoma. Observational study with total sampling. Data was obtained from the histopathologic with diagnosis of bronchogenic carcinoma in 1 year. Retrospectively, the data were obtained from the archives of thoracic CT examinations in Radiology and FOB examination in Lung Operating Room. The variables assessed were the finding of mass of endobronchial based on its location, the main bronchi constriction, lobar bronchi constriction, segmental bronchi constriction, and compression/tracheal deformity. The results of VB were examined by three radiologists independently and were then compared with the results of FOB. The observation results of VB and FOB were used to analyse the degree of conformity. There is a low level of agreement on the finding of endobronchial mass, lobar bronchi and segmental bronchi constriction, sufficient level of agreement on the main bronchial constriction finding. VB has a limited capacity to evaluate abnormalities of the tracheobronchial compared with FOB, but VB has an advantage in evaluating the patency of the distal airway of severe obstruction.

A Transparent Ultrasound Array for Real-time Optical, Ultrasound and Photoacoustic Imaging

Objective and Impact Statement: Simultaneous imaging of ultrasound and optical contrasts can help map structural, functional and molecular biomarkers inside living subjects with high spatial resolution. There is a need to develop a platform to facilitate this multimodal imaging capability to improve diagnostic sensitivity and specificity. Introduction: Currently, combining ultrasound, photoacoustic and optical imaging modalities is challenging due to complex arrangements, in order to co-align both optical and ultrasound waves within the same field of view, because conventional ultrasound transducer arrays are optically opaque. Methods: One elegant solution is to make the ultrasound transducer transparent to light. Here, we demonstrate a novel transparent ultrasound transducer (TUT) liner array fabricated using a transparent lithium niobate piezoelectric material for real-time multimodal imaging. Results: The TUT array consisted of 64 elements and centered at ~6 MHz frequency. We demonstrate a quad-mode ultrasound, Doppler ultrasound, photoacoustic and fluorescence imaging in real-time using the TUT array directly coupled to the tissue mimicking phantoms. Conclusion: The TUT array successfully showed a multimodal imaging capability, and has potential applications in diagnosing cancer, neuro and vascular diseases, including image-guided endoscopy and wearable imaging.

Hybrid handheld gamma-ultrasound prototype for radioguided surgery: initial results

We have witnessed impressive advances in preoperative imaging of cancer and the development of dualmodality scanners. However, there is a need for a scanner with functional and anatomical imaging capability suitable for surgical settings and radioguided surgery. The current paper introduces a handheld gamma-ultrasound scanner prototype and illustrates the initial result of testing its very first version. The result of the testing was promising and encouraging in continuing the further development of the prototype.

Design and Fabrication of CLYC-Based Rotational Modulation Collimator (RMC) System for Gamma-Ray/Neutron Dual-Particle Imager

Background: This work aims to develop a new imaging system based on a pulse shape discrimination-capable Cs2LiYCl6:Ce (CLYC) scintillation detector combined with the rotational modulation collimator (RMC) technique for dual-particle imaging.Materials and Methods: In this study, a CLYC-based RMC system was designed based on Monte Carlo simulations, and a prototype was fabricated. Therein, a rotation control system was developed to rotate the RMC unit precisely, and a graphical user interface-based software was also developed to operate the data acquisition with RMC rotation. The RMC system was developed to allow combining various types of collimator masks and detectors interchangeably, making the imaging system more versatile for various applications and conditions.Results and Discussion: Operational performance of the fabricated system was studied by checking the accuracy and precision of the collimator rotation and obtaining modulation patterns from a gamma-ray source repeatedly.Conclusion: The prototype RMC system showed reliability in its mechanical properties and reproducibility in the acquisition of modulation patterns, and it will be further investigated for its dual-particle imaging capability with various complex radioactive source conditions.

Sonographic Detection of Congenital Intestinal Malrotation: A Case Report

Intestinal malrotation is a rare fetal anomaly resulting from the failure of midgut rotation and fixation. Sonography is typically the first modality of choice for assessing pediatric pathology due to its high sensitivity, portability, real-time imaging capability, and non-ionizing technique; however, its role in diagnosing small bowel rotational anomalies remains limited and controversial. Fluoroscopic upper gastrointestinal imaging (UGI) is the primary diagnostic examination at most institutions. However, even on UGI, imaging findings may be equivocal. In such cases, sonography may provide additional information at facilities where it is not used as a primary diagnostic tool. This case report represents the first reported case showing how patient position is important as the typical vascular sonographic features of rotation were normal in one position but abnormal in another. In addition, this case shows how congenital intestinal malrotation was decisively diagnosed using sonographic imaging.

Imaging Capability at Close Range of High Frequency Ultrasound Transducer on the Perforation of Bony Walls Simulating Pedicle Screw Placement

Background: Ultrasound has been proved to be a promising alternative spine navigation method. High frequency ultrasound transducer has the advantage of high resolution on surface structure, but imaging at close range is difficult, especially in narrow space of the pilot-hole in pedicle.Methods: Twenty cortical bone chips were made and different size of hole with diameter of 1mm, 2mm, 3mm or 5mm was randomly carved in each bone chip. A tailored 30MHz high frequency transducer scanned bone samples at the distance of 4mm, 3mm, 2mm and 1mm. Successive transmission ringingeffect elimination, Hilbert transform and Gray-scale mapping method were utilized to process and optimize attained original images.Results: At the distance of 4mm, 3mm, 2mm and 1mm, the holes with diameter of 5mm, 3mm and 2mm could be discerned. At the distance of 1mm, only the holes with 5mm and 3mm could be clearly distinguished and the 2mm hole appeared obscure. The holes with diameter of 1mm could not be detected at any distance. The holes with diameter of 2mm were able to be detected at the distance of 1mm.Conclusions: This study indicated that the high frequency transducer had limited imaging capability at close range on the bony surface. These results lay a foundation for further developing a novel ultrasound-based spinal pedicle interior imaging and navigation system.

Chitosan oligosaccharide decorated liposomes combined with TH302 for photodynamic therapy in triple negative breast cancer

Background Triple negative breast cancer (TNBC) is an aggressive tumor with extremely high mortality that results from its lack of effective therapeutic targets. As an adhesion molecule related to tumorigenesis and tumor metastasis, cluster of differentiation-44 (also known as CD44) is overexpressed in TNBC. Moreover, CD44 can be effectively targeted by a specific hyaluronic acid analog, namely, chitosan oligosaccharide (CO). In this study, a CO-coated liposome was designed, with Photochlor (HPPH) as the 660 nm light mediated photosensitizer and evofosfamide (also known as TH302) as the hypoxia-activated prodrug. The obtained liposomes can help diagnose TNBC by fluorescence imaging and produce antitumor therapy by synergetic photodynamic therapy (PDT) and chemotherapy. Results Compared with the nontargeted liposomes, the targeted liposomes exhibited good biocompatibility and targeting capability in vitro; in vivo, the targeted liposomes exhibited much better fluorescence imaging capability. Additionally, liposomes loaded with HPPH and TH302 showed significantly better antitumor effects than the other monotherapy groups both in vitro and in vivo. Conclusion The impressive synergistic antitumor effects, together with the superior fluorescence imaging capability, good biocompatibility and minor side effects confers the liposomes with potential for future translational research in the diagnosis and CD44-overexpressing cancer therapy, especially TNBC. Graphic abstract