Computational vibration mitigation using phase interpolation in digital holographic microscopy for overlay metrology.

Digital holographic microscopy retrieves amplitude and phase information of an image which allows us to computationally correct for imperfections in the imaging optics. However, digital holographic microscopy is an interferometric technique that is inherently sensitive to undesired phase variations between object and reference beam. These phase variations lower the fringe contrast if they are integrated over a finite exposure time which leads to a reduced amplitude of the retrieved image.

Ex vivo optical coherence tomography combined with near infrared targeted fluorescence: towards esophageal cancer detection.

Early detection of (pre)malignant esophageal lesions is critical to improve esophageal cancer morbidity and mortality rates. In patients with advanced esophageal adenocarcinoma (EAC) who undergo neoadjuvant chemoradiation therapy, the efficacy of therapy could be optimized and unnecessary surgery prevented by the reliable assessment of residual tumors after therapy. Optical coherence tomography (OCT) provides structural images at a (sub)-cellular level and has the potential to visualize morphological changes in tissue.

Neuropathological hallmarks in the post-mortem retina of neurodegenerative diseases.

The retina is increasingly recognised as a potential source of biomarkers for neurodegenerative diseases. Hallmark protein aggregates in the retinal neuronal tissue could be imaged through light non-invasively. Post-mortem studies have already shown the presence of specific hallmark proteins in Alzheimer's disease, primary tauopathies, synucleinopathies and frontotemporal lobar degeneration.

Investigating the use of comprehensive motion monitoring for intrafraction 3D drift assessment of hypofractionated prostate cancer patients on a 1.5T magnetic resonance imaging radiotherapy system.

This work investigates the use of a multi-2D cine magnetic resonance imaging-based comprehensive motion monitoring (CMM) system for the assessment of prostate intrafraction 3D drifts. The data of six healthy volunteers were analyzed and the values of a clinically-relevant registration quality factor metric exported by CMM were presented. Additionally, the CMM-derived prostate motion was compared to a 3D-based reference and the 2D-3D tracking agreement was reported.

Theoretical and experimental determination of the confocal function of OCT systems for accurate calculation of sample optical properties.

The attenuation coefficient of biological tissue could serve as an indicator of structural and functional changes related to the onset or progression of disease. Optical coherence tomography (OCT) provides cross sectional images of tissue up to a depth of a few millimeters, based on the local backscatter properties. The OCT intensity also depends on the confocal function, which needs to be characterised to determine correctly the exponential decay of the intensity based on Lambert-Beer.

Frequency of Agreement Between Structural and Functional Glaucoma Testing: A Longitudinal Study of 3D OCT and Current Clinical Tests.

Purpose: To evaluate how often tests of structure and function detect glaucoma progression at the same study visit. Tests include current glaucoma clinical tests and a new 3-dimensional (3D) optical coherence tomography (OCT) rim measurement.

Design: Prospective cohort study.

Treatment planning evaluation and experimental validation of the magnetic resonance-based intrafraction drift correction.

Background And Purpose: MRI-guided online adaptive treatments can account for interfractional variations, however intrafraction motion reduces treatment accuracy. Intrafraction plan adaptation methods, such as the Intrafraction Drift Correction (IDC) or sub-fractionation, are needed. IDC uses real-time automatic monitoring of the tumor position to initiate plan adaptations by repositioning segments.

Confocal corrected attenuation coefficient imaging in phantoms and using chromatic focal shift calibration.

Optical coherence tomography (OCT) is conventionally used for structural imaging of tissue. Calibrating the intensity values of OCT images can give information on the tissue's inherent optical properties, such as the attenuation coefficient, which can provide an additional parameter to quantify possible pathological changes. To obtain calibrated intensity values, the focus position and Rayleigh length of the incident beam need to be known.

Gating and intrafraction drift correction on a 1.5 T MR-Linac: Clinical dosimetric benefits for upper abdominal tumors.

This work reports on the first seven patients treated with gating and baseline drift correction on the high-field MR-Linac system. Dosimetric analysis showed that the active motion management system improved congruence to the planned dose, efficiently mitigating detrimental effects of intrafraction motion in the upper abdomen.

α-Synuclein pathology in post-mortem retina and optic nerve is specific for α-synucleinopathies.

There is increasing interest in studying retinal biomarkers for various neurodegenerative diseases. Specific protein aggregates associated with neurodegenerative diseases are present in the retina and could be visualised in a non-invasive way. This study aims to assess the specificity and sensitivity of retinal α-synuclein aggregates in neuropathologically characterised α-synucleinopathies, other neurodegenerative diseases and non-neurological controls.

Deep learning for automated contouring of neurovascular structures on magnetic resonance imaging for prostate cancer patients.

Background And Purpose: Manual contouring of neurovascular structures on prostate magnetic resonance imaging (MRI) is labor-intensive and prone to considerable interrater disagreement. Our aim is to contour neurovascular structures automatically on prostate MRI by deep learning (DL) to improve workflow and interrater agreement.

Materials And Methods: Segmentation of neurovascular structures was performed on pre-treatment 3.

Swept-source multimode fiber imaging.

High-resolution compressive imaging via a flexible multimode fiber is demonstrated using a swept-laser source and wavelength dependent speckle illumination. An in-house built swept-source allowing for independent control of bandwidth and scanning range is used to explore and demonstrate a mechanically scan-free approach for high-resolution imaging through an ultrathin and flexible fiber probe. The computational image reconstruction is shown by utilizing a narrow sweeping bandwidth of [Formula: see text] nm while acquisition time is decreased by 95% compared to conventional raster scanning endoscopy.

Sub-diffraction computational imaging via a flexible multicore-multimode fiber.

An ultra-thin multimode fiber is an ideal platform for minimally invasive microscopy with the advantages of a high density of modes, high spatial resolution, and a compact size. In practical applications, the probe needs to be long and flexible, which unfortunately destroys the imaging capabilities of a multimode fiber. In this work, we propose and experimentally demonstrate sub-diffraction imaging through a flexible probe based on a unique multicore-multimode fiber.

A Common Active Intermediate in the Oxidation of Alkenes, Alcohols and Alkanes with HO and a Mn(II)/Pyridin-2-Carboxylato Catalyst.

The mechanism and the reactive species involved in the oxidation of alkenes, and alcohols with HO, catalysed by an prepared mixture of a Mn salt, pyridine-2-carboxylic acid and a ketone is elucidated using substrate competition experiments, kinetic isotope effect (KIE) measurements, and atom tracking with O labelling. The data indicate that a single reactive species engages in the oxidation of both alkenes and alcohols. The primary KIE in the oxidation of benzyl alcohols is ca.

Facilitating glaucoma diagnosis with intereye neuroretinal rim asymmetry analysis using spectral-domain optical coherence tomography.

Purpose: To determine whether intereye asymmetry of a three-dimensional neuroretinal rim parameter, the minimum distance band, is useful in differentiating normal eyes from those with open-angle glaucoma.

Materials And Methods: This is a cross-sectional study of 28 normal subjects and 33 glaucoma subjects. Subjects underwent spectral domain optical coherence tomography imaging of both eyes.

Field-position dependent apodization in dark-field digital holographic microscopy for semiconductor metrology.

Measuring overlay between two layers of semiconductor devices is a crucial step during electronic chip fabrication. We present dark-field digital holographic microscopy that addresses various overlay metrology challenges that are encountered in the semiconductor industry. We present measurement results that show that the point-spread function of our microscope depends on the position in the field-of-view.

Phosphorylated tau in the retina correlates with tau pathology in the brain in Alzheimer's disease and primary tauopathies.

The retina is a potential source of biomarkers for the detection of neurodegenerative diseases. Accumulation of phosphorylated tau (p-tau) in the brain is a pathological feature characteristic for Alzheimer's disease (AD) and primary tauopathies. In this study the presence of p-tau in the retina in relation to tau pathology in the brain was assessed.

Magnetic Resonance-Guided Adaptive Radiation Therapy for Prostate Cancer: The First Results from the MOMENTUM study-An International Registry for the Evidence-Based Introduction of Magnetic Resonance-Guided Adaptive Radiation Therapy.

Purpose: Magnetic resonance (MR)-guided radiation therapy (MRgRT) is a new technique for treatment of localized prostate cancer (PCa). We report the 12-month outcomes for the first PCa patients treated within an international consortium (the MOMENTUM study) on a 1.5T MR-Linac system with ultrahypofractionated radiation therapy.

Daily online contouring and re-planning versus translation-only correction in neurovascular-sparing magnetic resonance-guided radiotherapy for localized prostate cancer.

Neurovascular bundle (NVB) and internal pudendal artery (IPA) sparing during magnetic resonance-guided radiotherapy (MRgRT) for prostate cancer aims for preservation of erectile function. Our present workflow involves daily online contouring and re-planning on a 1.5 T MR-linac, as alternative to conventional (rigid) translation-only corrections of the prostate.

Clinical application of a sub-fractionation workflow for intrafraction re-planning during prostate radiotherapy treatment on a 1.5 Tesla MR-Linac: A practical method to mitigate intrafraction motion.

Background: Intrafraction motion during radiotherapy limits margin reduction and dose escalation. Magnetic resonance (MR)-guided linear accelerators (MR-Linac) have emphasised this issue by enabling intrafraction imaging. We present and clinically apply a new workflow to counteract systematic intrafraction motion during MR-guided stereotactic body radiotherapy (SBRT).