We demonstrate a computationally efficient method for correcting the nonuniform rotational distortion (NURD) in catheter-based imaging systems to improve endoscopic en face optical coherence ...tomography (OCT) and OCT angiography. The method performs nonrigid registration using fiducial markers on the catheter to correct rotational speed variations. Algorithm performance is investigated with an ultrahigh-speed endoscopic OCT system and micromotor catheter. Scan nonuniformity is quantitatively characterized, and artifacts from rotational speed variations are significantly reduced. Furthermore, we present endoscopic en face OCT and OCT angiography images of human gastrointestinal tract in vivo to demonstrate the image quality improvement using the correction algorithm.
The energy-balance equation was used to estimate evapotranspiration in a greenhouse, and an instrument was developed to collect data for this purpose. The values estimated by this method were in good ...agreement with the measured data. It was shown that the net solar radiation term was the largest and cannot be neglected, and that long-wave radiation exchange had a relatively small effect. As usual, soil heat flux can be neglected but the sensible heat transfer term cannot be neglected since the maximum of the possible range of values is large and significant.
It was concluded that the method used was simple and suitable for irrigation control in greenhouses. It was also concluded that normal radiation sensor measurements on a horizontal surface are not adequate for measuring radiation received by a plant canopy in a single-span greenhouse.
Biomedical applications of light scattering have traditionally relied on Mie theory as a theoretical basis for analyzing experimental measurements. While this approach is computationally accessible, ...the use of Mie theory cannot always account for the spheroidal nature of biological scatterers such as cell nuclei. As an alternative, we have developed light scattering codes based on the T-matrix formalism to analyze angle-resolved light scattering measurements. In this paper, we discuss the development of computer codes to create a database of scattering profiles, validation of the database using experimental measurements of tissue phantoms containing spheroidal scatterers, and recent applications of the approach to analyze the structure of cell nuclei. The reviewed studies show that while the T-matrix approach adds important information for some light scattering studies, the additional computational cost may not always be justified when compared to the Mie theory.
This study aimed to evaluate the use of ultrahigh-speed volumetric en face and cross-sectional optical coherence tomography (OCT) with micromotor catheters for the in vivo assessment of Barrett's ...esophagus and dysplasia.
74 OCT datasets with correlated biopsy/endoscopic mucosal resection histology (49 nondysplastic Barrett's esophagus NDBE, 25 neoplasia) were obtained from 14 patients with Barrett's esophagus and a history of dysplasia and 30 with NDBE. The associations between irregular mucosal patterns on en face OCT, absence of mucosal layering, surface signal > subsurface, and > 5 atypical glands on cross-sectional OCT vs. histology and treatment history were assessed by three blinded readers.
Atypical glands under irregular mucosal patterns occurred in 75 % of neoplasia (96 % of treatment-naïve neoplasia) vs. 30 % of NDBE datasets (43 % of short- and 18 % of long-segment NDBE). Mucosal layering was absent in 35 % of neoplasia and 50 % of NDBE datasets, and surface signal > subsurface occurred in 29 % of neoplasia and 30 % of NDBE datasets.
Atypical glands under irregular mucosal patterns are strongly associated with neoplasia, suggesting potential markers for dysplasia and a role in pathogenesis.
Rapid histological assessment of large areas of prostate tissue is required for many intraoperative consultation scenarios such as margin evaluation. Nonlinear microscopy (NLM) enables imaging of ...large (whole mount) specimens without freezing or cryotoming. This study demonstrates rapid histological imaging of unsectioned prostate cancer surgical specimens using nonlinear microscopy and compares features of prostate pathology to standard paraffin embedded H&E histology. Fresh or formalin fixed specimens were stained in 2.5 min with fluorescent nuclear and stromal dyes. Nonlinear microscopy images of unsectioned tissues were generated by nonlinear (two-photon) excitation of the fluorophores, where fluorescence is only emitted from tissue at the microscope focus, avoiding the need for physical sectioning. The images were displayed in real time using a color scale similar to H&E, then tissues were processed for standard paraffin embedded H&E histology. Seventy nonlinear microscopy and corresponding paraffin H&E images of fresh and fixed prostate specimens (15 cancer, 55 benign) from 24 patients were read by genitourinary pathologists to assess if nonlinear microscopy could achieve an equivalent evaluation to paraffin embedded H&E histology. Differences between nonlinear microscopy images and paraffin H&E slides, including cytoplasmic color and stromal density, were observed, however nonlinear microscopy images could be interpreted with minimal training. Nonlinear microscopy enabled visualization of benign, atrophic and hyperplastic glands and stroma, ejaculatory ducts, vasculature and inflammatory changes. Nonlinear microscopy enabled identification of typical and variants of adenocarcinoma, as well as Gleason patterns. Perineural invasion and extraprostatic extension could also be assessed. Nonlinear microscopy images closely resemble paraffin H&E slides and enable rapid assessment of normal prostate architecture, benign conditions, and carcinoma in freshly excised and fixed specimens. Nonlinear microscopy can image large regions of tissue, equivalent to multiple frozen section tissue blocks, within minutes because cryotoming/microtoming are not required, making it a promising technique for intraoperative consultation.
Improving the detection efficiency in nuclear emulsion trackers Alexandrov, A.; Bozza, C.; Buonaura, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2015, Letnik:
776
Journal Article
Recenzirano
Nuclear emulsion films are a tracking device with unique space resolution. Their use in nowadays large-scale experiments relies on the availability of automated microscope operating at very high ...speed. In this paper we describe the features and the latest improvements of the European Scanning System, a last-generation automated microscope for emulsion scanning. In particular, we present a new method for the recovery of tracking inefficiencies. Stacks of double coated emulsion films have been exposed to a 10GeV/c pion beam. Efficiencies as high as 98% have been achieved for minimum ionising particle tracks perpendicular to the emulsion films and of 93% for tracks with tan(θ)≃0.8.
New calibrations of CR39 and Makrofol nuclear track detectors have been obtained using 158AGeV Pb82+ and In49+ions; a new method for the bulk etch rate determination, using both cone height and base ...diameter measurements, was developed. The CR39 charge resolution based on the etch-pit base area measurements is adequate to identify nuclear fragments in the interval 7⩽Z/β⩽49. For CR39 the detection threshold is at REL ∼50MeVcm2g−1, corresponding to a nuclear fragment with Z/β∼7. Base cone area distributions for Makrofol foils exposed to Pb82+ ions have shown for the first time all peaks due to nuclear fragments with Z>50; the distribution of the etched cone heights shows well separated individual peaks for Z/β∼78 to 83 (charge pick-up). The Makrofol detection threshold is at REL ∼2700MeVcm2g−1, corresponding to a nuclear fragment with Z/β=50.
Advanced fluorescence imaging modalities such as confocal microscopy and two photon fluorescence microscopy can provide rapid, real-time histology images, but the mounting of fresh tissue specimens ...in standard orientations required for diagnosis without embedding and sectioning remains an unsolved problem. Here, we introduce a piston-based specimen holder designed for consistent, even pressure distribution. We improve upon previous designs by incorporating an air piston system with a flexible membrane and wick that extracts fluid during compression. We combine this with support fixtures to aid in the distribution of pressure, enabling imaging of specimens with small surface areas relative to their thickness, such as bisected shave skin biopsies in standard orientation without embedding or sectioning. We image both fresh biopsy specimens and diagnostic Mohs first stage specimens during clinical procedures, demonstrating improved visualization of the tissue surface in real time. Finally, we show that conventional cryosectioning can exaggerate the extent of margin positivity, which can be avoided using the piston-based holder.
Rapid histopathological examination of surgical specimen margins using fluorescence microscopy during breast conservation therapy has the potential to reduce the rate of positive margins on ...postoperative histopathology and the need for repeat surgeries. To assess the suitability of imaging modalities, we perform a direct comparison between confocal fluorescence microscopy and multiphoton microscopy for imaging unfixed tissue and compare to paraffin-embedded histology. An imaging protocol including dual channel detection of two contrast agents to implement virtual hematoxylin and eosin images is introduced that provides high quality imaging under both one and two photon excitation. Corresponding images of unfixed human breast tissue show that both confocal and multiphoton microscopy can reproduce the appearance of conventional histology without the need for physical sectioning. We further compare normal breast tissue and invasive cancer specimens imaged at multiple magnifications, and assess the effects of photobleaching for both modalities using the staining protocol. The results demonstrate that confocal fluorescence microscopy is a promising and cost-effective alternative to multiphoton microscopy for rapid histopathological evaluation of ex vivo breast tissue.
The energy of atmospheric neutrinos detected by MACRO was estimated using multiple Coulomb scattering of upward throughgoing muons. This analysis allows a test of atmospheric neutrino oscillations, ...relying on the distortion of the muon energy distribution. These results have been combined with those coming from the upward throughgoing muon angular distribution only. Both analyses are independent of the neutrino flux normalization and provide strong evidence, above the 4σ level, in favour of neutrino oscillations.
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