Image Navigation Research Articles

Generation of fused visible and thermal-infrared images for uncooperative spacecraft proximity navigation

State-of-the-art techniques for vision-based relative navigation rely on images acquired in the visible spectral band. Consequently, the accuracy and robustness of the navigation is strongly influenced by the illumination conditions. The exploitation of thermal-infrared images for navigation purposes is studied in the present paper, as a possible solution to improve navigation in close proximity with a target spacecraft. Thermal-infrared images depend on the thermal radiation emitted by the target, hence, they are independent from light conditions; however, they suffer from a poorer texture and a lower contrast with respect to visible ones. This paper proposes pixel-level image fusion to overcome the limitations of the two types of images. The two source images are merged into a more informative one, retaining the strengths of the distinguished sensing modalities. The contribution of this work is twofold: firstly, a realistic thermal infrared images rendering tool for artificial targets is implemented; secondly, different pixel-level visible-thermal infrared images fusion techniques are assessed through qualitative and quantitative performance metrics to ease and improve the subsequent image processing step. The work presents a comprehensive evaluation of the best fusion techniques for on-board implementation, paving the way to the development of a multispectral end-to-end navigation chain.

HDAC6 inhibitor loaded bimetallene nanosheets with antagonizing thermoresistance for augmented mild photothermal therapy

Photothermal therapy (PTT) induces thermoresistance through cellular heat shock response, which impairs the therapeutic efficacy of the PTT. To resolve this problem, we developed a photothermal theranostics (denoted as PMH), which integrated the photothermal conversion agent of PdMo bimetallene with histone deacetylase 6 (HDAC6) selected inhibitor (ACY-1215), showing the synergistic antitumor effect both in vitro and in vivo. Mechanistically, under the photoacoustic imaging (PA) navigation, the released ACY-1215 triggered by NIR laser irradiation decrease the heat shock proteins (HSPs) expression and weaken the HDAC6-regulated HSP90 deacetylation, thus hindering the degradation of PTT-induced misfolded or unfold proteins through proteasome dependent pathway. Moreover, mild photothermal therapy (mPTT) treatment compromised the autophagy, which induced by HDAC6 inhibition, leading to mPTT-induced misfolded or unfold proteins further accumulation. Given that inhibition of HDAC6 plus mPTT contribute to tumor eradication. This study develops a promising combination strategy based on mPTT for future cancer treatment.

Comparison of uniform‐density, variable‐density, and dual‐density spiral samplings for multi‐shot DWI

To compare the performances of uniform-density spiral (UDS), variable-density spiral (VDS), and dual-density spiral (DDS) samplings in multi-shot diffusion imaging, and determine a sampling strategy that balances reliability of shot navigator and overall DWI image quality. UDS, VDS, and DDS trajectories were implemented to achieve four-shot diffusion-weighted spiral imaging. First, the static B0 off-resonance effects in UDS, VDS, and DDS acquisitions were analyzed based on a signal model. Then, in vivo experiments were performed to verify the theoretical analyses, and fractional anisotropy (FA) fitting residuals were used to quantitatively assess the quality of spiral diffusion data for tensor estimation. Finally, the SNR performances and g-factor behavior of the three spiral samplings were evaluated using a Monte Carlo-based pseudo multiple replica method. Among the three spiral trajectories with the same readout duration, UDS sampling exhibited the least off-resonance artifacts. This was most evident when the static B0 off-resonance effect was severe. The UDS diffusion images had higher anatomical fidelity and lower FA fitting residuals than the other two counterparts. Furthermore, the four-shot UDS acquisition achieved the best SNR performance in diffusion imaging with 12.11% and 40.85% improvements over the VDS and DDS acquisitions with the same readout duration, respectively. UDS sampling is an efficient spiral acquisition scheme for high-resolution diffusion imaging with reliable navigator information. It provides superior off-resonance performance and SNR efficiency over the VDS and DDS samplings for the tested scenarios.

The orbit schemes to monitor Martian dust storms: Benefits to China’s future Mars missions

<p indent="0mm">Mars is most often the focus of planetary explorations because it promises to have signs of extraterrestrial life. China’s first Mars mission, called Tianwen-1, was launched on 22 May 2021 and was successful in “orbiting, landing and roving” the planet and exploring its environment. Following this success, China planned to carry out another Mars mission, known as Tianwen-3, to collect and return samples. However, dust storms posed a significant threat. Such activity on Mars has an evident pattern of seasonal variation, frequently occurring during spring and summer in the southern hemisphere. Under certain conditions, this dust activity can develop into a global storm, lasting several months, and can strongly perturb the upper atmosphere, which is crucial for the aerocapture of probes. Even regional storms can modify local visibility, temperature, wind, and the density of the lower and middle atmosphere, which impact parachutes, navigational imaging, and other decent-entry-landing and take-off probe processes. Indeed, the tiniest grains of dust pose a threat to human soft tissues and are harmful to the surface probes’ mechanisms and filters. Solar panels, cameras, etc., are also adversely impacted by dust deposition, which peaks during the fallout of a global dust storm. Thus, forecasting dust storms is invaluable for reducing or avoiding damage to these probes. However, the physical complexity of dust storms on Mars is not fully understood, making accurate forecasts of dust storms, and particularly their onset, challenging. To aid future Mars missions such as the Tianwen-3, we propose that China establish a network to monitor Martian dust storms and atmospheric weather that is based on observations of Mars from a spacecraft constellation. This constellation consists of three spacecraft in an equatorial synchronous orbit with an altitude of about <sc>17000 km</sc> and one spacecraft in a large-elliptic polar orbit whose perigee altitude is about <sc>150 km.</sc> The constellation with “four-point integration” can form a monitoring and alert network that provides simultaneous, continuous, and global-scale observations of the Martian atmosphere and surface. As an innovative platform for space-based science, this network has many advantages for Mars exploration, because it can monitor Martian dust storms and geomorphic changes on the surface, as well as the space environment and atmospheric weather. It is also beneficial for spacecraft relaying communication from probes on the Martian surface, allowing continuous data to be uplinked. Finally, the constellation is an ideal platform for on-orbit computing, delivering computer resources to surface assets, and global navigation of Mars.

The sound of the ingenuity Helicopter on Mars

The sounds of the Ingenuity Helicopter flying in the Martian atmosphere are among the most notable recordings of the microphone on the SuperCam instrument on the Mars 2020 Perseverance Rover. Distinct acoustic signatures of the helicopter were recorded on the 4th, 5th, 6th, and 8th flights. The detected signatures are around 84 Hz and (occasionally) at 168 Hz, at the blade crossing frequency and its first harmonic. Several higher harmonics were prominent in hover tests in short-range recordings in a test chamber on Earth; these are attenuated by CO2 absorption at the 50 m-plus ranges on Mars. Doppler shift of the 84 Hz signal can be measured and is consistent with the trajectory measured with Ingenuity’s navigation camera and inertial navigation unit, and documented by Perseverance’s cameras. A striking feature of the sound recordings is an unanticipated deep modulation of the signals with nulls spaced by around 15–20 s, superposed on the simple and expected decline in amplitude with distance. We have evaluated and rejected models of multipath sound interference as requiring implausibly strong near-surface temperature gradients. We find instead that the modulation appears to be the signature of a slight asynchrony between the rotation rates of the two coaxial rotors, such that the blade-crossing azimuth rotates slowly during flight, resulting in a “lighthouse” sweeping of the radiated sound pattern. Analysis of blade orientations seen in the shadow of the helicopter observed in down-looking navigation images supports this model.

NIR-II fluorescence lymphatic imaging and intraoperative navigation based on the “isolated cage” monodisperse strategy

Fluorescence imaging in the second near-infrared (NIR-II) window is well suited for biological systems due to lower tissue scattering and micrometer-scale resolution at depths of millimeters. Unfortunately, none of the NIR-II fluorophores have clinical application due to low quantum yields, poor photostability, and long-term biosafety concerns. Herein, we develop NIR-II fluorescent nanoprobes based on the "isolated cage" monodisperse strategy, which significantly inhibits the π-π stacking interactions and restricts internal rotation of the arrested indocyanine green (ICG) fluorophores, which minimizes aggregation-caused quenching and enhances their NIR-II imaging performance. Unlike ICG's imaging window of several minutes, the nanoformulations have reduced photobleaching and provide longer observation times. The increased imaging time allows high spatiotemporal resolution of blood vessels and lymphatic system. Benefiting from the high resolution and sensitivity of the nanoprobes, sentinel lymph nodes are accurately removed under fluorescence navigation. More intriguingly, the patency of lymphovenous anastomosis (LVA) is presented more intuitively by qualitative and quantitative NIR-II fluorescence signals, which will directly benefit the innovation and promotion of LVA.

Flow-Permeable and Tunable Metalens for Subdiffraction Waterborne-Sound Focusing

Metalenses with high-efficiency focusing functionality and a water-flow-permeable structure are desired in various acoustic applications, such as medical imaging and underwater navigation. Here, we propose a design paradigm for a metalens for waterborne sound with a compact and simple configuration. The metalens is composed of an open central region reserved as a steady water-flow channel, and a metagrating-based peripheral region consisting of a grating of meta-atoms. Each meta-atom containing two elliptical iron cylinders is smartly designed according to the grating diffraction theory and intelligent optimization algorithm, so that it can deflect a normally incident wave along the desired direction toward the focal spot. In this way, subdiffraction focusing with a high energy concentration ratio is achieved, which breaks the conventional Rayleigh-Abbe diffraction limit in the focal plane. Here the subdiffraction focusing is due to the coherent interference in the far field of the \ifmmode\pm\else\textpm\fi{}first-order diffracted waves from each meta-atom, and is attributed to the superoscillation phenomenon. Interestingly, the focal depth of the metalens can be conveniently tuned by applying a background water flow with different velocities and directions, and the superresolution focusing effect is sustained regardless of whether there is a water flow or not. Since the magnitude and direction of the water-flow velocity can be electrically controlled, the compact and open configuration of the metalens not only provides a flexible and practical solution for sharp and controllable sound focusing, but also has potential applications in metagrating-based planar acoustic devices.

4D lung MRI with high-isotropic-resolution using half-spoke (UTE) and full-spoke 3D radial acquisition and temporal compressed sensing reconstruction

Objective. To develop a respiratory motion-resolved four-dimensional (4D) magnetic resonance imaging (MRI) technique with high-isotropic-resolution (1.1 mm) using 3D radial sampling, camera-based respiratory motion sensing, and temporal compressed sensing reconstruction for lung cancer imaging. Approach. Free-breathing half- and full-spoke 3D golden-angle radial acquisitions were performed on eight healthy volunteers and eight patients with lung tumors of varying size. A back-and-forth k-space ordering between consecutive interleaves of the 3D radial acquisition was performed to minimize eddy current-related artifacts. Data were sorted into respiratory motion states using camera-based motion navigation and 4D images were reconstructed using temporal compressed sensing to reduce scan time. Normalized sharpness indices of the diaphragm, apparent signal-to-noise ratio (aSNR) and contrast-to-noise ratio (CNR) of the lung tumor (patients only), liver, and aortic arch were compared between half- and full-spoke 4D MRI images to evaluate the impact of respiratory motion and image contrast on 4D MRI image quality. Respiration-induced changes in lung volumes and center of mass shifts were compared between half- and full-spoke 4D MRI measurements. In addition, the motion measurements from 4D MRI and the same-day 4D CT were presented in one of the lung tumor patients. Main results. Half-spoke 4D MRI provides better visualization of the lung parenchyma, while full-spoke 4D MRI presents sharper diaphragm images and higher aSNR and CNR in the lung tumor, liver, and aortic arch. Lung volume changes and center of mass shifts measured by half- and full-spoke 4D MRI were not statistically different. For the patient with 4D MRI and same-day 4D CT, lung volume changes and center of mass shifts were generally comparable. Significance. This work demonstrates the feasibility of a motion-resolved 4D MRI technique with high-isotropic-resolution using 3D radial acquisition, camera-based respiratory motion sensing, and temporal compressed sensing reconstruction for treatment planning and motion monitoring in radiotherapy of lung cancer.

User's image perception improved strategy and application of augmented reality systems in smart medical care: A review.

Augmented reality (AR) is a new human-computer interaction technology that combines virtual reality, computer vision, and computer networks. With the rapid advancement of the medical field towards intelligence and data visualisation, AR systems are becoming increasingly popular in the medical field because they can provide doctors with clear enough medical images and accurate image navigation in practical applications. However, it has been discovered that different display types of AR systems have different effects on doctors' perception of the image after virtual-real fusion during the actual medical application. If doctors cannot correctly perceive the image, they may be unable to correctly match the virtual information with the real world, which will have a significant impact on their ability to recognise complex structures. This paper uses Citespace, a literature analysis tool, to visualise and analyse the research hotspots when AR systems are used in the medical field. A visual analysis of the 1163 articles retrieved from the Web of Science Core Collection database reveals that display technology and visualisation technology are the key research directions of AR systems at the moment. This paper categorises AR systems based on their display principles, reviews current image perception optimisation schemes for various types of systems, and analyses and compares different display types of AR systems based on their practical applications in the field of smart medical care so that doctors can select the appropriate display types based on different application scenarios. Finally, the future development direction of AR display technology is anticipated in order for AR technology to be more effectively applied in the field of smart medical care. The advancement of display technology for AR systems is critical for their use in the medical field, and the advantages and disadvantages of various display types should be considered in different application scenarios to select the best AR system.

Precision Navigation of Venous Thrombosis Guided by Viscosity-Activatable Near-Infrared Fluorescence.

Thrombus are blood clots formed by abnormal hemostasis in blood vessels and are closely associated with various diseases such as pulmonary embolism, myocardial infarction and stroke. Early diagnosis and treatment of thrombus is the key to reducing the high risk of thrombotic disease. Given that early thrombus is small in early size, free instability, wide regional distribution and fast formation, it is urgent to develop all-inclusive detection methods that combine high signal-to-noise ratio, in situ dynamic and rapid in-depth tissue imaging. Near-infrared (NIR) fluorescence imaging, with its excellent high spatiotemporal resolution and tissue penetration depth, is a powerful technique for direct visualization of thrombotic events in situ. Considering the fibrin highly expressed in the thrombus is a typical thrombotic target. Moreover, the viscosity of the thrombus is markedly higher than its surroundings. Therefore, we developed a fibrin-targeting and viscosity-activating thrombus NIR fluorescent probe (TIR-V) for high-resolution and high-sensitivity in situ lighten-up thrombus. TIR-V has the advantages of good thrombus targeting, significant "off-on" fluorescence specific response to viscosity, bright NIR fluorescence and good biocompatibility. The thrombus is clearly delineated by a high signal-to-noise ratio NIR fluorescence imaging, enabling imaging detection and precise navigation of thrombotic regions. This work demonstrates the potential of TIR-V as a bifunctional probe for definitive diagnostic imaging and direct navigation of thrombotic lesions in clinical applications.

Au/Mn nanodot platform for in vivo CT/MRI/FI multimodal bioimaging and photothermal therapy against tongue cancer.

Surgical resection is the main method for oral tongue squamous cell carcinoma (OTSCC) treatment. However, the oral physiological function and aesthetics may be seriously damaged during the operation with a high risk of recurrence. Therefore, it is important to develop an alternative strategy with precise guidance for OTSCC treatment. Herein, multifunctional Au/Mn nanodots (NDs) are designed and synthesized. They can perform multimodal bioimaging, including computed tomography (CT) and magnetic resonance imaging (MRI) simultaneously, and exhibit bright near-infrared fluorescence imaging (FI) for navigation, and even integrate photothermal therapy (PTT) property. The localization of OTSCC relies on visual and tactile cues of surgeons while lacking noninvasive pretreament labeling and guidance. Au/Mn NDs provide CT/MRI imaging, giving two means of accurate positioning pretherapy. Meanwhile, the fluorescence of the Au/Mn NDs in the near-infrared region (NIR) is beneficial for noninvasive labeling and intuitive observation with the naked eye to determine the tumor boundary during PTT. Further, Au/Mn NDs showed excellent results in ablating tumors in vivo. Above all, the Au/Mn NDs provide a key platform for multimodal bioimaging and PTT in a single nanoagent, which demonstrated attractive performance for OTSCC treatment.

Closed-loop active control of the magnetic capsule endoscope with a robotic arm based on image navigation

This paper proposes a novel approach for the closed-loop active control of the magnetic capsule endoscope based on image navigation. The proposed method uses a robotic arm to control the rotation of an external permanent magnet (EPM) to generate a rotating magnetic field. Subsequently, this rotating magnetic field controls the motion of the magnetic capsule endoscope (MCE). A gyroscope was included inside the MCE to obtain its posture. Using the image captured by the camera installed in the MCE, a relationship between the relative position of the MCE and the intestine was established. Based on the relative position relationship and the MCE’s posture, the MCE was controlled to move along the intestinal center by the robotic arm, thus, the closed-loop active control of the MCE was achieved. Furthermore, the feasibility of closed-loop active control of the MCE was verified through the isolated porcine small intestine experiment. Experimental results show that the closed-loop active control combined with image navigation is not only easy to operate, but also offers high stability in terms of control mechanism, and suitability for use in clinical applications.

Deploying Indocyanine Green Fluorescence-Guided Navigation System in Precise Laparoscopic Resection of Pediatric Hepatoblastoma.

Background: Hepatoblastoma (HB) is the most common form of liver cancer in children. To date, complete tumor resection is still the gold standard for treating HB. Indocyanine green (ICG) has been identified as a sensitive adjunct that is highly effective in the identification and surgical management of local and metastatic HB. It has thus becomes an increasingly popular choice among surgeons in HB resection surgeries that are fluorescence-guided. However, laparotomy remains the preferred choice in most cases since the applications and limitations of fluorescence-guided laparoscopic surgery in treating HB remain unclear. In this study, the characteristics and outcomes of laparoscopic HB resections that were guided by intraoperative ICG fluorescent imaging were investigated. Methods: Seven HB patients underwent ICG-guided laparoscopic HB resection surgery from August 2019 to December 2021. ICG was intravenously administered to the patients at a dosage of 0.5 mg/kg 48 h prior to the scheduled operation. During operation, tumor localization and resection boundary were guided by fluorescence visualization. The data on surgical and clinical features were collected retrospectively. Results: The resection area and tumor boundary could be clearly viewed in real-time under the ICG fluorescence imaging navigation system during operation, except for one patient who had received interventional chemoembolization before surgery. The image produced by laparoscopic fluorescence navigation was clear since it was not affected by ambient light. All tumors were completely resected as confirmed by negative margins for HB during postoperative pathological examination. No residual or recurrence were also found through computed tomography during follow-up visits from 9 to 37 months. Conclusions: ICG fluorescence-guided laparoscopic surgery is safe and effective in treating HB due to its ability to provide clear information on tumor localization and delineate tumor margins in real-time.

Functionalized polydopamine nanospheres as in situ spray for photothermal image-guided tumor precise surgical resection

Surgical resection is a critical procedure for treatment of solid tumor, which commonly suffers from postoperative local recurrence due to the possibility of positive surgical margin. Although the widely used clinical imaging techniques (CT, MRI, PET, etc.) show beneficial effects in providing a macroscopic view of preoperative tumor position, they are still failing to provide intraoperative real-time imaging navigation during the surgery and need oral or intravenous injection contrast agents with risk of adverse effects. In this work, we present a nano-spray assisted photothermal imaging system for in vitro cells discrimination as well as in vivo visualization of tumor position and border that guides real-time precise tumor resection during surgery (even for tiny tumor less than 3 mm). Herein, the nano-spray were prepared by RGD peptide functionalized polydopamine (PDA-RGD) nanospheres with excellent photothermal conversion efficiency (54.27%), stability and reversibility, which target ανβ3 integrin overexpressed tumor cells. Such PDA-RGD serve as nanothermometers that convert and amplify biological signal to intuitive thermal image signal, depicting the tumor margin in situ. In comparison to conventional imaging techniques, our approach through topical spraying together with portable infrared camera has the characteristics of low cost, convenient, no radiation hazard, real-time intraoperative imaging-guidance and avoiding the adverse effects risk of oral or intravenous contrast agent. This technology provides a new universal tool for potentially assisting surgeons’ decision in real-time during surgery and aiding to improved outcome.

Bringing Radiology Education to a New Reality: A Pilot Study of Using Virtual Reality as a Remote Educational Tool.

Purpose: We investigated virtual reality (VR) during a 2-week, undergraduate, radiology elective to determine if it improved learning outcomes and user satisfaction. Methods: Eighteen students enrolled between August 2021 and February 2022. Each student had a collaborative Zoom teaching session with a preceptor using a Picture Archive and Communications System (PACS)-like viewing system Online DICOM Image Navigator (ODIN), followed by a teaching session using a VR, Digital Imaging and Communications in Medicine (DICOM) viewer (SieVRt). After each teaching session, the students independently reviewed 8 imaging cases and completed case related questions. The students completed a survey, rating their subjective experiences using ODIN and SieVRt. Results: There was no difference in total test scores between the two learning strategies. However, students did perform statistically better on two of five questions designed to test the detection/measurement capabilities of SieVRt vs ODIN. Students stated that they preferred using SieVRt over ODIN and agreed that they were able to view subtle imaging findings and abnormalities better using SieVRt. However, students found that some of the functions of SieVRt (measuring angles/lengths, and multitasking) were difficult. There were technical challenges with VR and minor undesirable physical effects (dizziness, nausea, etc.). Conclusions: Virtual reality has the potential to enhance radiology education by providing an immersive and engaging experience. Objectively, students were able to perform two tasks better with SieVRt. Subjectively, the VR platform received favourable reviews from students for a variety of features. There were reported technical and physical challenges related to using VR. Future developments in VR systems should focus on improving the user experience.

Advances in magnetic particle imaging and perspectives on liver imaging

Magnetic particle imaging (MPI) is an emerging technique to visualize the spatial distribution of superparamagnetic iron oxide (SPIO) with high temporal-spatial resolution, high sensitivity, unlimited image depth, and true quantitative information. MPI is based on the nonlinear response of SPIO in an alternating magnetic field without tissue background noise. It is a promising imaging modality for various applications, including vascular imaging, cell tracking, tumor imaging, and catheter navigation. Many applications of liver imaging could be improved or created with MPI. In this review, we cover the principle and construction of MPI, we evaluate the features and advantages of MPI with relation to its own rationale and via comparison with other imaging modalities, and we review MPI liver imaging applications with a view towards assisting hepatic researchers in drawing inspiration.

영상 식별 및 항법 정확도 향상을 위한 적대적 오토인코더 기반 전처리 알고리즘

This paper presents an adversarial auto-encoder (AAE) based preprocessing algorithm for improving image identification and navigation accuracy. The AAE is a fusion of the variational auto-encoder and generative adversarial network. The proposed preprocessing algorithm is a neural network structure for unsupervised image restoration that redesigns the loss function by using the earth mover’s distance (EMD) to improve training efficiency. Using the EMD parameter, it is confirmed that the estimation error was smaller than those of various parameters measuring the distance between the two distributions. In addition, we confirmed that the proposed approach has better efficiency than existing loss functions, such as the mean square error or cross entropy, for artificial intelligence learning.

An Apoptotic Body‐based Vehicle with Navigation for Photothermal‐Immunotherapy by Precise Delivery and Tumor Microenvironment Regulation

AbstractTumor precision therapy and preventing tumor recurrence and metastasis are the main challenges to tumor eradication. Herein, an apoptotic body‐based vehicle with imaging navigation is developed for precise tumor delivery and photothermal‐immunotherapy by IR820‐conjugated apoptotic body loaded with R848 nanoparticles. The apoptotic body serves as ammunition stores as well as vehicle drive engines, while IR820 acts as a fluorescence imaging navigation and photothermal controlling system. The apoptotic body vehicle can deliver the ammunition to tumor and achieve deep penetration by macrophage‐hitchhiking. Fluorescence imaging navigation opens a control window for photothermal treatment, followed by photothermal triggering of in situ vaccine formation. Further, CD47 antibody loaded hydrogel strengthens innate and adaptive immunity, simultaneously the polarization of macrophages regulates the immunosuppressive microenvironment to further promote the combined antitumor immunotherapy. With breast tumor (4T1)‐bearing mice model, the apoptotic body vehicle performs excellent therapeutic efficacy for primary tumor, distant tumor, tumor metastasis, and recurrence prevention.

AdaFI-FCN: an adaptive feature integration fully convolutional network for predicting driver’s visual attention

ABSTRACT Visual Attention Prediction (VAP) is widely applied in GIS research, such as navigation task identification and driver assistance systems. Previous studies commonly took color information to detect the visual saliency of natural scene images. However, these studies rarely considered adaptively feature integration to different geospatial scenes in specific tasks. To better predict visual attention while driving tasks, in this paper, we firstly propose an Adaptive Feature Integration Fully Convolutional Network (AdaFI-FCN) using Scene-Adaptive Weights (SAW) to integrate RGB-D, motion and semantic features. The quantitative comparison results on the DR(eye)VE dataset show that the proposed framework achieved the best accuracy and robustness performance compared with state-of-the-art models (AUC-Judd = 0.971, CC = 0.767, KL = 1.046, SIM = 0.579). In addition, the experimental results of the ablation study demonstrated the positive effect of the SAW method on the prediction robustness in response to scene changes. The proposed model has the potential to benefit adaptive VAP research in universal geospatial scenes, such as AR-aided navigation, indoor navigation, and street-view image reading.

Implementation of the use of SPECT-portable for evaluation of surgical margins in breast cancer with indication of ROLL: First results

ObjectivesMain objective: To compare the effectiveness for checking surgical margins between SPECT-portable and mammography of the piece (RxM). Secondary objectiveTo standardize a pre-operative protocol using SPECT-portable and to evaluate the time required in the use of this technique. Material and methodsProspective longitudinal study with 36 patients (39 lesions) diagnosed with breast cancer (CM) with criteria for SNOLL/ROLL.A pre-surgical study of the tumor lesion was performed, after the eco-guided administration of 99mTc-nanocolloids of albumin/99mTc-macroaggregates of albumin, in the tumor lesion. Hybrid images (optical + SPECT) and 3D navigation images with gamma probe are obtained using freehandSPECT.In the operating room, 4–5 images are obtained with freehandSPECT, (I) on skin for tumor location, (II) after exposure of surgical bed for resection guide, (III) of the surgical bed after exeresis, (IV and V) the anterior–posterior and lateral surface of the surgical specimen. The three criteria to decide to extend the margins are: (a) residual activity (cps) at the edges of the surgical bed resection; (b) visual analysis of the uptake in the specimen; (c) a minimum distance of 10 mm from the edges of the specimen to the center of greatest uptake, plus the radius of the lesion.We study the concordance of: the depth measurement between ultrasound and freehandSPECT; the surgical margins between freehandSPECT vs. mammography of the specimen (RxM), considering anatomical pathology (AP) as the gold standard technique as reference; surgical time used with freehandSPECT and RxM. ResultsIntraoperative localization was performed in all cases.False negative (FN: no detection margin affected) with freehandSPECT: 9 margins; with RxM: 8. True positive (TP: detection margin affected) with freehandSPECT: 5 margins, with RxM: 6. True negative (TN: consider free margin when healthy) with freehandSPECT: 213 margins; with RxM: 196. Negative predictive value (NPV: probability of negative margin on unaffected part) with freehandSPECT: 95.9%, with RxM: 96.07%. Specificity with freehandSPECT: 96.8%, with RxM: 97%.The concordance of surgical bed margins between freehandSPECT and RxM: 94.5%. Between freehandSPECT and AP: 93.1%. Between RxM and PA: 93.5%, being all statistically significant (p-value <0.000), so we can affirm that both techniques are related or dependent on the reference technique, the PA. Degree of correlation between SPECT-portable and low PA (Kappa index: 0.34, 95% CI [0.22–0.47], and between RxM and moderate PA (Kappa index: 0.42, 95% CI [0.29–0.56], p-value <0.001. Comparison of the successes and failures of both techniques (SPECT-portable and RxM) and PA: Distribution χ2: 0.023 with degree of freedom 1, with value <0.05, so we can affirm that both techniques are similar, since there are no significant statistical differences.Median total OR time: 60.25 min (30–145). Mean freehandSPECT OR time: 5 scans = 10 min. ConclusionsThere are no statistically significant differences in the probability to rule out affective margins that require a second surgery between both techniques (SPECT-portable and RxM) so, the technique performed with SPECT-Portable is a useful and effective procedure, which requires specific training with an optimized and multidisciplinary protocol. The time spent with SPECT-portable is feasible for daily practice.