Optical Tomography System Research Articles

Effects of cold storage on double integrating sphere optical property measurements of porcine dermis and subcutaneous fat from 400 to 1100nm.

Accurate values of skin optical properties are essential for developing reliable computational models and optimizing optical imaging systems. However, published values show a large variability due to a variety of factors, including differences in sample collection, preparation, experimental methodology, and analysis. We aim to explore the influence of storage conditions on the optical properties of the excised skin from 400 to 1100nm. We utilize a double integrating sphere system and inverse adding-doubling approach to determine absorption, , and reduced scattering, , coefficients of the porcine dermis and subcutaneous fat before and after refrigeration, freezing, or flash freezing. Our findings indicate a small average change of , , and in for the dermis and 0.001, , and for the subcutaneous tissue after refrigeration, freezing, and flash freezing, respectively, with the most notable differences observed in the hemoglobin absorption region. The value of shows a negligible average change of , , and for the dermis, and 0.06, , and change for the subcutaneous tissue for refrigerated, frozen, and flash-frozen samples, respectively. The results provide additional context for the variability of published values of optical parameters and enable informed selection of sample storage conditions for future measurements. In addition, the results discussed here can be used to improve study planning, particularly with regard to maximizing the use of finite samples that have been collected.

Automated feature selection for early keratoconus screening optimization

In this paper, an automated feature selection (FS) method is presented to optimize machine learning (ML) models' performances, enhancing early keratoconus screening. A total of 448 parameters were analyzed from a dataset comprising 3162 observations sourced from the swept source optical coherence tomography imaging system developed by the Chinese Academy of Sciences Institute of Automation (SS-1000 CASIA OCT) and electronic health records (EHR). To identify the most relevant features, the analysis of variance (ANOVA) method was used in this study. The performance of three classifiers namely K-Nearest Neighbors (KNN), Support Vector Machine (SVM), and Artificial Neural Networks (ANN) was evaluated, yielding classification accuracies of 96.79% and 96.68% for KNN, 98.95% and 97.08% for SVM, and 95.64% and 95.62% for ANN when distinguishing between 2 and 4 keratoconus classes, respectively. The results show that selecting 50 features can significantly improve the performance of the model while reducing the computation time. The automated feature selection method can also assist ophthalmologists in better understanding the links between various ocular characteristics and keratoconus, potentially leading to advances in early diagnosis, risk prediction, and clinical management of this condition.

WS2/Graphene/MoS2 Sandwich van der Waals Heterojunction for Fast-Response Photodetectors.

Fast-response photodetectors have attracted considerable attention in the application of high-speed communication, real-time monitoring, and optical imaging systems. However, most reported photodetectors suffer from limitations of the inherent properties of materials, low carrier transport efficiency, and unmatched interfaces, which lead to a low response speed. Here, we report a WS2/graphene/MoS2 vertical van der Waals heterojunction fabricated by mechanical exfoliation and dry transfer methods for fast response. To improve the response speed of the previously reported WS2/MoS2 heterojunction with excellent photoelectric performances, the embedded graphene is employed to optimize the interface defects and improve the carrier transport efficiency due to its high mobility and smooth and flat surface. Under the illuminations of a 405 nm laser and a bias voltage of 0.5 V, our device can realize rise and fall times of 44 and 52 μs, respectively. For a bias voltage of 2.5 V, moreover, the device can also show outstanding performances including a high responsivity of 220 A/W, a considerable detectivity of 1.2 × 1013 Jones, a large external quantum efficiency of 6.7 × 104 %, and a low dark current of 1.05 × 10-13 A. Additionally, the device enables high-speed transmission with a low bit error rate in a closed-loop optical communication system. Therefore, the proposed scheme can provide an idea for the design of photodetectors with fast response and high performance.

Advanced Diagnostic and Therapeutic Approaches for Effective Management of Bladder Malignancies

Background Effectual management of bladder malignancies (BMs) is currently a global challenge due to their expensive therapeutic and diagnostic cost burden, together with augmented progression/recurrence rate. Purpose This review aimed to explore cutting-edge diagnostic and therapeutic techniques for meeting the current clinical requirements for effectively managing BMs encompassing dual muscle-invasive bladder tumors (MIBT) and nonmuscle-invasive bladder tumors (NMIBT). Methods A comprehensive review of relevant literature (including data review from 2019 to 2024) was performed to collect valuable information regarding the utilization of advanced diagnostic and therapeutic techniques for the effective management of BMs. Results Studies investigating the potential applications and possible limitations of various methods, including UroVysion, continuous bladder irrigation (CBI), transurethral resection of bladder tumor (TURBT), laparoscopic, and robot-abetted extended pelvic lymph node dissection (PLND), 3D culture models and nerve spring technique (NST) in robotic intracorporeal Studer’s orthotopic neobladder (RISON) have been examined. Similarly, the role of Urothelial Piezo channels (Piezo1 and Piezo2) in urinary system modulation, human epidermal growth factor receptor (HER2)-selective therapy in metastatic urothelial carcinoma (MUC) patients, and diagnostic benefits of fluorescence in situ hybridization (FISH) in BMs have been analyzed. Current report enlisted the major clinical applications associated with the advanced diagnostic and therapeutic techniques with consequent management of lower urinary tract malfunctions (LUTMs), stress urinary incontinence, and BMs, including both MIBT, NMIBT, and MUC. Conclusion This review provided detailed information on numerous benefited outcomes attained from different approaches such as augmented bladder functioning, implementation of collective optical and cancer-specific imaging systems, utilization of tumor-specific biomarkers, precise tumor amputation, reduced urinary complications and hospital stay, postoperative comfort, limited invasiveness, limited blood loss, and ultimately reduced recurrence rates. BMs management at the clinical level needs to be effectively rationalized to enhance the patient’s quality of life and reduce the ultimate cost burden over bladder cancer patients together with appropriate management of associated limitations like urinary tract infections, bladder perforation, bladder infections, and carcinoma relapse in postoperative cases should effectively be encountered to further improve the therapeutic potential of advanced techniques in the near future.

Molecular Imaging of Tumor-Infiltrating Lymphocytes in Living Animals Using a Novel mCD3 Fibronectin Scaffold.

The interaction between cancer cells and immune cells in the tumor microenvironment (TME) plays a crucial role in determining tumor growth, metastasis, and response to treatment. Tumor-infiltrating lymphocytes (TILs) in TME could be a predictive marker for treatment response in various therapeutic interventions, including chemotherapy and immunotherapy. Thus, imaging the tumor immune microenvironment is important for selecting the optimal treatment strategies in cancer therapy. The CD3 protein represents a promising target for diagnostic imaging of TILs in vivo to assess the immune state of the TME. Although many anti-CD3 antibodies have been explored for this application, the nonspecific immune activation by these antibodies limits their applications. To overcome this issue, we engineered a novel fibronectin III domain (FN3) protein binder (mCD3-FN3;11.8 kDa) against mouse CD3 antigen protein using a yeast display library to image TILs homing in vivo into the TME. We performed in vitro and in vivo assays to test the mCD3-FN3 binder purity as well as in vivo targetability in mouse models of syngeneic tumors. We used near-infrared 800 dye conjugated with mCD3-FN3 (IR800-mCD3-FN3) for in vivo tracking of TILs via optical imaging. We used three different syngeneic tumors in mice (mCD3+ EL4 tumor in C57BL/6 mice, mCD3- CT26 colon tumor, and mCD3- 4T1 breast tumor in BALB/c mice) for imaging TILs in vivo. C57BL/6 mice bearing EL4 tumors were separated into two groups (blocking [Blk] and nonblocking [Nblk]; n = 3 per group) and used for in vivo imaging. Blocking groups received 200 μg of unlabeled mCD3-FN3 2 h prior to the administration of IR800-mCD3-FN3 binder. Each mouse was administered with 25 μg of the IR800-mCD3-FN3 binder and tracked using an IVIS optical imaging system over time. C57BL/6/EL4 mice were imaged at 4 and 24 h post injection of the IR800-mCD3-FN3 binder, and mouse organs were collected at 24 h after final imaging and used for ex vivo histological imaging. In CT26 and 4T1 tumor models, TILs in TME were imaged 4, 24, and 48 h after binder injection. The NIR imaging of EL4 tumors showed that IR800-mCD3-FN3 can detect both TILs within the tumor and the tumor cells with a high signal-to-background ratio 24 h after initial binder injection with a total radiant efficiency (mean TRE ± SD) of 6.5 × 1010 ± 1.5 × 1010 [photons/s]/[μW/cm2]. The animals received preinjection of unlabeled mCD3-FN3(Blk) prior to IR800-mCD3-FN3 binder administration and showed a significant level of fluorescence signal reduction (mean TRE ± SD: 1.6 × 1010 ± 4.1 × 109) in the tumor when compared to the EL4-Nblk tumors (p = 0.006). The mouse group with CT26 and 4T1 tumors where the probe can only bind to TILs within the tumor showed a specific imaging signal (mean TRE ± SD) of 1.1 × 1011 ± 5.2 × 1010 and 9.5 × 1010 ± 4.6 × 1010, respectively, at 48 h p.i. For these groups, the ex vivo tumor-to-muscle ratios were 20- and 27-fold for CT26 and 4T1 tumors, respectively. These results clearly demonstrate the in vivo binding ability of the mCD3-FN3 binder to mCD3 marker expressed by T cells in the TME. The ex vivo histological analysis of tumors, and the organs of animals with EL4 tumors, and TILs imaging of CT26, and 4T1 tumors (at 48 p.i.) confirmed that the IR800-mCD3-FN3 probe was able to specifically bind to CD3 markers expressed by the T cells. In summary, both in vitro and in vivo data indicated that the engineered mCD3-FN3 binder by this study is a promising ligand for diagnostic imaging of tumors in vivo for the assessment of mCD3 expressing TILs in the TME. This can be used as a prognostic marker in evaluating tumor response to therapeutic intervention as well as a diagnostic marker in imaging tumor response to immune checkpoint blockade cancer therapies.

An Ultrafast Optical Imaging System with Anamorphic Transformation Based on STEAM Structure

An Ultrafast Optical Imaging System with Anamorphic Transformation Based on STEAM Structure

Optical Imaging of Trigeminal Ganglion Excitation Evoked by Electrical Stimulation of the Trigeminal Nerve.

Background There are many reports of anatomical and physiological studies on trigeminal ganglion neurons, but few studies have analyzed temporal changes in the excitation of the trigeminal ganglion. This study aimed to establish an experimental system for spatial and temporal imaging analysis of the excitatory dynamics of trigeminal ganglion cells evoked by stimulation of a peripheral branch of the trigeminal nerve. Methods After excision of the trigeminal ganglion with the inferior alveolar nerve (IAN) from Sprague Dawley rats (seven to nine weeks old), 400-µm-thick slices of the trigeminal ganglion with the IAN were prepared. Real-time optical imaging was performed using cell membrane voltage-sensitive dye, Di4-ANEPPS, and changes in fluorescence intensity ratio (ΔF/F) were analyzed. Results Electrical stimulation of the IAN evoked the excitation of the trigeminal ganglion at the lateral surface area first, followed by expansion to the inner area. The calculated conduction velocity was 0.72 ± 0.49 m/s. This response was diminished by tetrodotoxin perfusion, but it was not observed in the C fiber-deficient rats. Conclusions A real-time optical imaging system can visualize the excitation of the trigeminal ganglion evoked by C-fiber stimulation.

Thermal optical aberrations correction via postprocessing in a raw domain

Optical imaging systems are susceptible to severe performance degradation when exposed to extreme temperature fluctuations. While extensive athermalization can mitigate such environmental effects, the complex design process, material limitations, and prohibitive cost greatly restrict its practical application. Herein, we propose what we believe to be a novel postprocessing scheme to compensate for the thermal-induced degradation. We simulate degraded raw image pairs based on optical point spread functions (PSFs) across a range of temperatures. To perform effective restoration, a PSF-guided neural network is specially designed. Experiments conducted on a customized digital-single-lens-reflex (DSLR) camera lens demonstrate that our solution successfully removes the thermal optical aberrations in both synthetic and experimentally captured scenes. Notably, our proposed approach outperforms several state-of-the-art (SOTA) deblurring methods, showcasing great promise for broad applicability in thermal-challenged imaging systems.

Calibration of liquid crystal spatial light modulators by using the double-phase method

In this manuscript, two diffraction-based methods for calibrating liquid crystal spatial light modulators are demonstrated theoretically and experimentally. They rely on the coherent interference of two uniform waves whose complex functions are encoded in a single-phase diffractive optical element by using the double-phase method. The interference pattern, recorded in the output plane of a spatially filtered 4f optical imaging system, allows calibration curves to be determined by post-processing. With these methods, both global and local phase calibrations can be performed, allowing inhomogeneous phase responses in liquid crystal displays to be evaluated and tested in a variety of experimental scenarios, such as multiwavelength illumination or varying incidence angles.

Comparative study of generalized-sampling-theorem-based digital super-resolution for 2D data

The size of pixels in a digital recording device, such as a CCD array, limits the spatial resolution in images obtained by an optical imaging system, thereby degrading the image quality. Digital super-resolution (DSR) techniques are used to reconstruct a high-resolution (HR) image from multiple sub-pixel-shifted low-resolution images in order to improve the image quality. In this article, we formulate a mathematical framework for DSR using the generalized sampling theorem (GST). The GST-based DSR method’s performance is evaluated by comparing it to existing resolution enhancement methods on the basis of evaluation metrics like percentage mean square error (%MSE), structural similarity index measure (SSIM), and peak signal-to-noise ratio (PSNR). The GST DSR method exhibits an overall superior quality image reconstruction based on quantitative analysis (with a near zero %MSE, SSIM around one, and improved PSNR in dB) and qualitative comparison. The robustness of the GST DSR method is further demonstrated in the presence of frame-to-frame shift estimation error using %MSE and SSIM by comparing it with multi-frame interpolation approaches.

Автоматизация визуального контроля фотошаблонов для изделий микроэлектроники

The choice of a specific research topic was caused by a request for the development and implementation of automatic optical inspection at a semiconductor plant. The purpose of the work was to develop requirements, conduct technical design and create an optical control system for geometry deviations from a photomask drawing and a conductive pattern obtained using a manual stencil printer using relatively inexpensive equipment. As a result of the research, a pilot design sample of an automated optical control system using relatively inexpensive equipment was created and a computational algorithm was developed that ensures increased performance of the visual image recognition system, which allows to significantly reduce the percentage of defects. The work describes the implemented algorithm for obtaining images by an optical system and extracting images from a drawing file. Regardless of the method of obtaining an image (optical system, scanning electron microscope), there remains interest in choosing a criterion for comparing the obtained image with the reference one. The paper studies quantitative empirical metrics - Mean Square Error and Peak Signal-to-Noise Ratio for various noise reduction methods Block-Matching and 3D filtering and the classical spatial filtering method of Gaussian blur. The sensitivity of the structural similarity index metric to structural distortions of images after noise reduction is checked, taking into account the minimum values of the structural elements of metal-ceramic housings. Based on the Rosner test applied to the obtained values of the structural similarity metric, images containing defects are identified. The user interface provides for the output of the image area with a defect to the operator's screen.

Spectroscopic and Photometric Confirmation of 3 Globular and 14 Intermediate-age Clusters in the Irr II Galaxy NGC 3077

We present the results from spectroscopic and photometric analysis of 17 globular cluster (GC) candidates in the Irr II galaxy NGC 3077. The GC candidates were selected on the Hubble Space Telescope images and were cleaned of foreground Galatic stars using the GAIA parameters. We carried out aperture photometry using the multiband archival images from the Sloan Digital Sky Survey, Two Micron All Sky Survey of all candidates, and low resolution (R = 1000) spectroscopic observations of 12 GC candidates and three suspected foreground stars using the Optical System for Imaging and Low-Intermediate-Resolution Integrated Spectroscopy/Multi-Object Spectra mode at the Gran Telescopio Canarias. Age, metallicity, and extinction values were determined using both spectroscopic and photometric data, independently. We find three of the 17 candidates are old (age > 10 Gyr), metal-poor ([Fe/H] < −1.0 dex), and massive (mass > 105 M ⊙) GCs with characteristics similar to the classical GCs in the Milky Way. The rest are intermediate-age clusters (IACs) with typical ages of 3–4 Gyr and in general metal-rich clusters. The radial velocities of both populations are within 100 km s−1 of the recessional velocity of the host galaxy. A relatively large population of IACs and low value of GC specific frequency (S N = 0.7) suggest that the preinteraction galaxy was actively forming stars and star clusters, and is unlikely to be a dwarf elliptical as suggested in some previous works.

Detection Capability Analysis of Field of View-Gated Optical Imaging System for All-Time Star Sensor

The field of view (FOV)-gated optical imaging system can relieve the contradiction between a wide FOV and the effective suppression of sky background radiation, making it particularly suitable for all-time star sensors. The detection capability of this novel optical imaging system during daytime differs significantly from that of traditional optical systems. This paper presents the principle of suppressing sky background radiation through FOV-gated imaging. Subsequently, the detection capabilities, including detectable limiting stellar magnitude and the probability of detecting at least three stars, are analyzed for applications on airborne platforms operating at altitudes of no less than 3km. Based on the analysis results, an FOV-gated imaging system operating in the shortwave infrared wavelength band was designed. Additionally, stray light analysis software, ASAP, was employed to simulate the illumination of stellar signals and sky background radiation on the detector. The evaluation of the detection capability of the designed FOV-gated optical system, based on simulation data, aligns with the theoretical analysis value. It demonstrates the system’s ability to detect multiple stars with a high probability during the daytime, thereby providing a theoretical foundation for the practical application of the FOV-gated optical imaging system on airborne platforms.

Custom chromatic confocal microscope for surface profilometry

In this work, a surface profiling system is introduced, employing a custom-designed chromatic confocal (CC) distance sensor. Today’s commercial sensors based on the CC principle have a major drawback of effectively coupling light from the illumination source into the optical imaging system, mainly due to etendue mismatch. Consequently, a substantial amount of light is lost, significantly reducing the overall SNR of the system. This limitation restricts its applicability primarily to highly reflective surfaces. To address this issue, an etendue-matched optical system is proposed, that incorporates an innovative superluminescent light source. Through this approach, the system achieves 4 orders of magnitudes higher illumination intensity concentrated within the focus spot compared to existing devices in the current market.

Retrieval of stratospheric aerosol extinction coefficients from sun-normalized Ozone Mapper and Profiler Suite Limb Profiler (OMPS-LP) measurements

Abstract. A new retrieval approach for obtaining vertical profiles of the aerosol extinction coefficient from measurements of scattered solar light in the limb-viewing geometry made by the Ozone Mapper and Profiler Suite Limb Profiler (OMPS-LP) instrument is presented. In contrast to many other published limb-scatter retrievals, our new algorithm does not employ normalization by a limb measurement at an upper tangent height. Instead, the measured limb radiances are normalized to solar irradiance. The main advantage of this approach is an almost complete elimination of the dependence of the retrieval results on the prior aerosol extinction profile used in the retrieval. This makes the retrieval better suited for the analysis of observation scenes with highly elevated aerosol plumes, such as those that occurred after the Hunga Tonga–Hunga Ha′apai volcanic eruption in January 2022. The results from the new approach were compared to the vertical profiles of the aerosol extinction coefficients retrieved from the Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS) and the Optical Spectrograph and InfraRed Imaging System (OSIRIS). In general, agreement within 25 % between the different data products was observed in the 18–23 km altitude range, although larger differences were seen after very strong volcanic eruptions and wildfires. In comparison with OSIRIS, larger differences are seen at high southern latitudes (above 60° S). The new data product was used to investigate the evolution of the aerosol plume after the Hunga Tonga–Hunga Ha′apai volcanic eruption.

A Real-Time Chemical Vapor Deposition Optical Monitoring System for Ge1-XSnx Growth Optimization

GeSn has attracted tremendous attention due to its tunable bandgap in recent decades. While the material has been produced through various methods, the Chemical Vapor Deposition (CVD) process has become one of the most essential for fabricating GeSn material since it was first demonstrated. However, the process is generally studied as a black box through input versus output. For example, one could study the change in temperature versus growth rate where changes in film thickness due to temperature change can be plotted only after the growth is finished. Process improvements from the study of these black box studies have yielded understandings in the growth kinematics and the development of growth recipes defining specific growth windows for different films that in many cases are very well understood. The black box treatment of CVD growth studies lacks near real-time feedback for the growth of the film leading to unsuccessful growths that in some cases slow research and in others lead to reduced yields of useful samples for device fabrication.Real-time monitoring of the process both in-situ and ex-situ is essential, as these could enhance understanding of the CVD process and growth dynamics. In this research, we have been developing a sophisticated optical imaging system to monitor the wafer surface morphology with desired magnification and specific areas of a sample during growth. By coupling an optical microscope system and a high-resolution portable imaging system via ports into the CVD reactor, the growth of a sample can be monitored in real time at both the micro and macro scale. As schematically shown in Figure 1, a microscope and an LED light source are mounted to the two 2¾” flanges with an angle of incidence symmetrical along the chamber's vertical center line, and the portable camera is nearly vertically mounted at one of the reactor's optical windows below the horizontal axis. The microscope and the portable camera are designated for distinct functions, a characteristic that is determined by their respective locations and magnification capabilities. By meticulously calculating and applying geometric and optical design principles, such as the imaging area, solid angles, and reflection, we can capture real-time images of the sample surface during its growth.Specifically, using this optical monitoring setup, we could observe the surface morphological change during a GeSn growth on Ge-Vs sample on a Si (100) substrate. This observation led to the early identification of defect formation and post-growth progression of defect formation during the cooling down process. Figure 2 is an example picture taken during the growth for an as-grown GeSn sample showing surface defects indicated by grey spots and edge and surface roughening by the orangish center region noted in the image. This capability would allow for the optimization of growth parameters throughout the entire process that result in larger areas of useful material or provide feedback that allows CVD operators to promptly respond and decide on the subsequent growth early to prevent lost time due to failed growths.Future work is to be accomplished by improvements in the optical system to not only allow for better image quality by using a different camera allowing better focusing, and higher frame rates as well as adjusting light source angle and/or incident camera angle. Acknowledgments The work is supported by the Air Force Office of Scientific Research (AFOSR) (Grant No.: FA9550-19-1-0341, FA9550-20-1-0168). Figure 1

EFCformer: high-resolution image restoration network for optical synthetic aperture imaging system

Synthetic-aperture optical imaging systems use multiple sub aperture arrays to significantly improve the imaging resolution of space telescopes. However, the sub aperture arrangement inevitably impacts the intermediate and low frequencies of the modulation transfer function, which results in blurred images. This study led to the proposal of a dual-feature extraction network based on convolution and a transformer, to effectively recover high-resolution images from synthetic aperture optical systems. Specifically, the proposed network consists of a new convolution layer for local feature extraction and a new transformer layer that focuses on global information. The introduction of concentrated linear attention and a newly developed gated forward propagation module enables the computational load of the transformer to be reduced to ultimately improve the ability to extract global information. To avoid any adverse effects by the ringing phenomenon generated in the synthetic aperture optical imaging system during image restoration, we used a new feature enhancement fusion module to combine the extracted features of the convolution and transformer layers and enhance them to strengthen the ability to sharpen the expression of the structural features. The experimental results indicated that, compared with other advanced methods, our method can improve the peak signal-to-noise ratio by 1.5% and reduce the number of model parameters by 17% to effectively restore the high-resolution image of the synthetic aperture optical system.

Ultrahigh-performance and broadband photodetector from visible to shortwave infrared band based on GaAsSb nanowires

Novel compact multispectral photodetectors detect various wavelengths, enabling visible light (VIS) and short-wave infrared (SWIR) dual-band detection for target identification and imaging. Nevertheless, combining VIS and SWIR photodetectors for multispectral detection faces challenges due to structural design and integration complexities. To streamline integration hurdles, high-Sb composition large-diameter GaAsSb nanowire photodetectors were developed, minimizing recombination centers and boosting gain. These photodetectors exhibit a high response in the light range from VIS (400 nm) to SWIR (2000 nm), exhibiting an ultrasensitive rise time (τr) of ∼0.8 ms, ultrahigh responsivity (R) of ∼2.32 × 105 A/W, and excellent detectivity (D*) of ∼9.10 × 1013 Jones in VIS (532 nm), and rapid τr of ∼6.5 ms, high R of ∼4.83 × 103 A/W with D* of ∼6.43 × 1011 Jones in SWIR (1300 nm), surpassing most previously reported III-V NW-based photodetectors. The simplified single GaAsSb NW photodetector significantly reduces the structural complexity and integration, achieving an ultrahigh-performance broadband optical response from the VIS to the SWIR region. The proposed broadband photodetector offers a potential approach for streamlining the integration of VIS/SWIR technologies and is expected to be applied in optical communication, monitoring, and imaging systems.

CREST: a Climate Data Record of Stratospheric Aerosols

Abstract. Climate-related studies need information about the distribution of stratospheric aerosols, which influence the energy balance of the Earth's atmosphere. In this work, we present a merged dataset of vertically resolved stratospheric aerosol extinction coefficients, which is derived using data from six limb and occultation satellite instruments: SAGE (Stratospheric Aerosol and Gas Experiment) II on ERBS (Earth Radiation Budget Satellite), GOMOS (Global Ozone Monitoring by Occultation of Stars) and SCIAMACHY (Scanning Imaging Spectrometer for Atmospheric Chartography) on Envisat, OSIRIS (Optical Spectrograph and InfraRed Imaging System) on Odin, OMPS (Ozone Monitor Profiling Suite Limb Profiler) on Suomi NPP, and SAGE III on the ISS (International Space Station). The merging of aerosol profiles is performed via the transformation of the aerosol datasets from individual satellite instruments to the same wavelength (750 nm) and their de-biasing and homogenization by adjusting the seasonal cycles. After such homogenization, the data from individual satellite instruments are in good agreement. The merged aerosol extinction coefficient is computed as the median of the adjusted data from the individual instruments. The merged time series of vertically resolved monthly mean aerosol extinction coefficients at 750 nm is provided in 10° latitudinal bins from 90° S to 90° N, in the altitude range from 8.5 to 39.5 km. The time series of the stratospheric aerosol optical depth (SAOD) is created via the integration of aerosol extinction profiles from the tropopause to 39.5 km; it is also provided as monthly mean data in 10° latitudinal bins. The created aerosol climate record covers the period from October 1984 until December 2023, and it is intended to be extended in the future. The merged CREST aerosol dataset (v2) is available at https://doi.org/10.57707/fmib2share.dfe14351fd8548bcaca3c2956b17f665 (Sofieva et al., 2024a). It can be used in various climate-related studies.

Reproducibility and stability of voluntary deep inspiration breath hold and free breath in breast radiotherapy based on real-time 3-dimensional optical surface imaging system

BackgroundThe aim of this study was to evaluate the inter-fraction reproducibility and intra-fraction stability of breast radiotherapy using voluntary deep-inspiration breath hold (DIBH) and free breathing (FB) based on an optical surface imaging system (OSIS).MethodsSeventeen patients (510 breath-hold sessions) treated using a field-in-field (FiF) technique and twenty patients (600 breath-free sessions) treated with a volume-modulated arc therapy (VMAT) technique were included in this retrospective study. All the patients were positioned with the guidance of CBCT and OSIS, and also monitored with OSIS throughout the whole treatment session. Eight setup variations in three directions were extracted from the treatment reports of OSIS for all sessions and were subsequently manually introduced to treatment plans, resulting in a total of 296 perturbed plans. All perturbed plans were recalculated, and the dose volume histograms (DVH) for the target and organs at risk (OAR) were analyzed.ResultsThe OSIS and CBCT for both DIBH and FB treatments showed a good agreement of less than 0.30 cm in each direction. The intra-fraction respiratory motion data during DIBH were −0.06 ± 0.07 cm, 0.12 ± 0.15 cm, and 0.12 ± 0.12 cm in the lateral, longitudinal, and vertical directions, respectively; for FB, the respiratory motion data were −0.02 ± 0.12 cm, 0.08 ± 0.18 cm, and 0.14 ± 0.20 cm, respectively. For the target, DIBH plans were more sensitive to setup errors; the mean deviations in D95 for CTV were 39.78 Gy–40.17 Gy for DIBH and 38.46 Gy–40.52 Gy for FB, respectively. For the OARs, the mean deviations of V10, V20, and Dmean to the heart; V5, V20, and Dmean to the ipsilateral lung; and Dmean to the breast were lower for the FB plan compared with the DIBH plan.ConclusionBased on OSIS, our results indicate that both DIBH and FB can provide good reproducibility in the inter-fractions and stability in the intra-fractions. When the patient respiratory motion is large, the FB technology has greater possibility for the undercoverage of the target volume, while DIBH technology is more likely to result in increases in dose to OARs (the lung, heart, and contralateral breast).