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Background: To investigate efficiency, accuracy and clinical benefit of a new augmented reality system for 3D laparoscopic liver surgery.Methods: All patients who received laparoscopic liver resection by a new image-guided surgery system with augmented 3D-imaging in a university hospital were included for analysis. Digitally processed preoperative cross-sectional imaging was merged with the laparoscopic image. Intraoperative efficiency of the procedure was measured as time needed to achieve sufficient registration accuracy. Technical accuracy was reported as fiducial registration error (FRE). Clinical benefit was assessed trough a questionnaire, reporting measures in a 5-point Likert scale format ranging from 1 (high) to 5 (low).Results: From January to March 2018, ten laparoscopic liver resections of a total of 18 lesions were performed using the novel augmented reality system. Median time for registration was 8:50 min (range 1:31-23:56). The mean FRE was reduced from 14.0 mm (SD 5.0) in the first registration attempt to 9.2 mm (SD 2.8) in the last attempt. The questionnaire revealed the ease of use of the system (1.2, SD 0.4) and the benefit for resection of vanishing lesions (1.0, SD 0.0) as convincing positive aspects, whereas image registration accuracy for resection guidance was consistently judged as too inaccurate.Conclusions: Augmented reality in 3D laparoscopic liver surgery with landmark-based registration technique is feasible with only little impact on the intraoperative workflow. The benefit for detecting particularly vanishing lesions is high. For an additional benefit during the resection process, registration accuracy has to be improved and non-rigid registration algorithms will be required to address intraoperative anatomical deformation. [ABSTRACT FROM AUTHOR]

Block copolymer nanostructures are an intriguing class of materials and during recent years increasing interest is being devoted to develop strategies for site-selective chemistry within one of the constituting domains. One of the most frequently employed strategies is crosslinking, either permanently (through, e.g. , radical crosslinking), by introducing reversible covalent bonds, or via electrostatic interactions. In addition to crosslinking, the selective addressing of suitable building blocks by hydrogen bonding or the introduction of functional groups at junction points between adjacent segments broadens both the range of accessible morphologies as well as the toolbox for interface modification. We try to provide a brief overview why addressing individual domains is of interest and highlight recent progress for the most prominent approaches. Further, we selected two application fields, which (to our opinion) represent exciting areas of research and, at the same time, have benefitted tremendously from recent progress in (block co-) polymer chemistry. In both cases we expect significant progress, either in terms of substrate scope for block copolymer membranes or regarding the bottom-up design of interfaces in nanostructured hybrid materials. [ABSTRACT FROM AUTHOR]

Abstract: We present an in-depth study of the UV-induced crosslinking of the polybutadiene domains in lamellar polystyrene-block-polybutadiene (PS-b-PB) block copolymer films. The crosslinking process is followed by a combination of depth-sensing indentation, Raman spectroscopy, and differential scanning calorimetry (DSC) investigations. Indentation assesses changes in the mechanical properties of the overall polymer films while Raman experiments directly monitor the consumption of the PB double bonds. Immediately after a short UV exposure, a loose network is formed and the glass transition temperature increases, whereas changes in the mechanical properties of the materials require far longer hardening times. We show that both processes are strongly affected by the amount of crosslinker (Lucirin-TPO®) added (within a range of 5 to 50 wt. % with respect to the PB fraction of the material). [Copyright &y& Elsevier]

Abstract: This paper describes the open source framework MARVIN for rapid application development in the field of biomedical and clinical research. MARVIN applications consist of modules that can be plugged together in order to provide the functionality required for a specific experimental scenario. Application modules work on a common patient database that is used to store and organize medical data as well as derived data. MARVIN provides a flexible input/output system with support for many file formats including DICOM, various 2D image formats and surface mesh data. Furthermore, it implements an advanced visualization system and interfaces to a wide range of 3D tracking hardware. Since it uses only highly portable libraries, MARVIN applications run on Unix/Linux, Mac OS X and Microsoft Windows. [Copyright &y& Elsevier]

Abstract: Introduction: Recent advances in medical imaging have brought post-mortem minimally invasive computed tomography (CT) guided percutaneous biopsy to public attention. Aims: The goal of the following study was to facilitate and automate post-mortem biopsy, to suppress radiation exposure to the investigator, as may occur when tissue sampling under computer tomographic guidance, and to minimize the number of needle insertion attempts for each target for a single puncture. Methods and materials: Clinically approved and post-mortem tested ACN-III biopsy core needles (14 gauge×160mm) with an automatic pistol device (Bard Magnum, Medical Device Technologies, Denmark) were used for probe sampling. The needles were navigated in gelatine/peas phantom, ex vivo porcine model and subsequently in two human bodies using a navigation system (MEM centre/ISTB Medical Application Framework, Marvin, Bern, Switzerland) with guidance frame and a CT (Emotion 6, Siemens, Germany). Results: Biopsy of all peas could be performed within a single attempt. The average distance between the inserted needle tip and the pea centre was 1.4mm (n =10; SD 0.065mm; range 0–2.3mm). The targets in the porcine liver were also accurately punctured. The average of the distance between the needle tip and the target was 0.5mm (range 0–1mm). Biopsies of brain, heart, lung, liver, pancreas, spleen, and kidney were performed on human corpses. For each target the biopsy needle was only inserted once. The examination of one body with sampling of tissue probes at the above-mentioned locations took approximately 45min. Conclusions: Post-mortem navigated biopsy can reliably provide tissue samples from different body locations. Since the continuous update of positional data of the body and the biopsy needle is performed using optical tracking, no control CT images verifying the positional data are necessary and no radiation exposure to the investigator need be taken into account. Furthermore, the number of needle insertions for each target can be minimized to a single one with the ex vivo proven adequate accuracy and, in contrast to conventional CT guided biopsy, the insertion angle may be oblique. Navigation for minimally invasive tissue sampling is a useful addition to post-mortem CT guided biopsy. [Copyright &y& Elsevier]

The development of responsive and multiresponsive polymers is gaining interest as they enable the development of more and more complex responsive materials. In this contribution, the synthesis and solubility behavior of well-defined poly(methyl acrylate) (PMA) and poly(diethylene glycol ethyl ether acrylate) (PDEGEA) homopolymers as well as PMA- block -PDEGEA block copolymers is reported. At first, a solubility screening of the homopolymers in ethanol–water solvent mixtures was performed in a high-throughput experimentation (HTE) manner using parallel turbidimetry, which revealed that in 35 wt% ethanol PMA undergoes an upper critical solution temperature (UCST) phase transition while PDEGEA undergoes a lower critical solution temperature phase transition in this solvent mixture. Moreover, the thermoresponsive self-assembly of PMA- b -PDEGEA block copolymers in water and ethanol were investigated by turbidimetry and DLS revealing UCST-induced disassembly of the micelles in ethanol and LCST-induced clustering of the micelles in water. Finally schizophrenic behavior of the PMA- b -PDEGEA block copolymers in 35 wt% ethanol is demonstrated. [ABSTRACT FROM AUTHOR]

• Optical tracking with intraoperative imaging offers accurate surgical navigation. • Navigation can be updated intraoperatively using fluoroscopy. • Initial registration and updates require placement of fiducials around the lesion. • Local accuracy after updates is comparable to new computed tomography imaging. • Sufficient local accuracy for guidance in resections with wider margins. In laparoscopic liver resection, surgeons conventionally rely on anatomical landmarks detected through a laparoscope, preoperative volumetric images and laparoscopic ultrasound to compensate for the challenges of minimally invasive access. Image guidance using optical tracking and registration procedures is a promising tool, although often undermined by its inaccuracy. This study evaluates a novel surgical navigation solution that can compensate for liver deformations using an accurate and effective registration method. The proposed solution relies on a robotic C-arm to perform registration to preoperative CT/MRI image data and allows for intraoperative updates during resection using fluoroscopic images. Navigation is offered both as a 3D liver model with real-time instrument visualization, as well as an augmented reality overlay on the laparoscope camera view. Testing was conducted through a pre-clinical trial which included four porcine models. Accuracy of the navigation system was measured through two evaluation methods: liver surface fiducials reprojection and a comparison between planned and navigated resection margins. Target Registration Error with the fiducials evaluation shows that the accuracy in the vicinity of the lesion was 3.78 ± 1.89 mm. Resection margin evaluations resulted in an overall median accuracy of 4.44 mm with a maximum error of 9.75 mm over the four subjects. The presented solution is accurate enough to be potentially clinically beneficial for surgical guidance in laparoscopic liver surgery. [ABSTRACT FROM AUTHOR]

Purpose: Ocular anatomy and radiation-associated toxicities provide unique challenges for external beam radiation therapy. For treatment planning, precise modeling of organs at risk and tumor volume are crucial. Development of a precise eye model and automatic adaptation of this model to patients' anatomy remain problematic because of organ shape variability. This work introduces the application of a 3-dimensional (3D) statistical shape model as a novel method for precise eye modeling for external beam radiation therapy of intraocular tumors. Methods and Materials: Manual and automatic segmentations were compared for 17 patients, based on head computed tomography (CT) volume scans. A 3D statistical shape model of the cornea, lens, and sclera as well as of the optic disc position was developed. Furthermore, an active shape model was built to enable automatic fitting of the eye model to CT slice stacks. Cross-validation was performed based on leave-one-out tests for all training shapes by measuring dice coefficients and mean segmentation errors between automatic segmentation and manual segmentation by an expert. Results: Cross-validation revealed a dice similarity of 95%±2% for the sclera and cornea and 91%±2% for the lens. Overall, mean segmentation error was found to be 0.3±0.1 mm. Average segmentation time was 14±2 s on a standard personal computer. Conclusions: Our results show that the solution presented outperforms state-of-the-art methods in terms of accuracy, reliability, and robustness. Moreover, the eye model shape as well as its variability is learned from a training set rather than by making shape assumptions (eg, as with the spherical or elliptical model). Therefore, the model appears to be capable of modeling nonspherically and nonelliptically shaped eyes. [ABSTRACT FROM AUTHOR]