Structured illumination ophthalmoscope: super-resolution microscopy on the living human eye

Design and development of a personalized virtual reality-based training system for vascular intervention surgery

BACKGROUND AND OBJECTIVES

Virtual training has emerged as an exceptionally effective approach for training healthcare practitioners in the field of vascular intervention surgery. By providing a simulated environment and blood vessel model that enables repeated practice, virtual training facilitates the acquisition of surgical skills in a safe and efficient manner for trainees. However, the current state of research in this area is characterized by limitations in the fidelity of blood vessel and guidewire models, which restricts the effectiveness of training. Additionally, existing approaches lack the necessary real-time responsiveness and precision, while the blood vessel models suffer from incompleteness and a lack of scientific rigor.

METHODS

To address these challenges, this paper integrates position-based dynamics (PBD) and its extensions, shape matching, and Cosserat elastic rods. By combining these approaches within a unified particle framework, accurate and realistic deformation simulation of personalized blood vessel and guidewire models is achieved, thereby enhancing the training experience. Furthermore, a multi-level progressive continuous collision detection method, leveraging spatial hashing, is proposed to improve the accuracy and efficiency of collision detection.

RESULTS

Our proposed blood vessel model demonstrated acceptable performance with the reduced deformation simulation response times of 7 ms, improving the real-time capability at least of 43.75 %. Experimental validation confirmed that the guidewire model proposed in this paper can dynamically adjust the density of its elastic rods to alter the degree of bending and torsion. It also exhibited a deformation process comparable to that of real guidewires, with an average response time of 6 ms. In the interaction of blood vessel and guidewire models, the simulator blood vessel model used for coronary vascular intervention training exhibited an average response time of 15.42 ms, with a frame rate of approximately 64 FPS.

CONCLUSIONS

The method presented in this paper achieves deformation simulation of both vascular and guidewire models, demonstrating sufficient real-time performance and accuracy. The interaction efficiency between vascular and guidewire models is enhanced through the unified simulation framework and collision detection. Furthermore, it can be integrated with virtual training scenarios within the system, making it suitable for developing more advanced vascular interventional surgery training systems.

Spatially modulated illumination microscopy: application perspectives in nuclear nanostructure analysis

Thousands of genes and the complex biochemical networks for their transcription are packed in the micrometer sized cell nucleus. To control biochemical processes, spatial organization plays a key role. Hence the structure of the cell nucleus of higher organisms has emerged as a main topic of advanced light microscopy. So far, a variety of methods have been applied for this, including confocal laser scanning fluorescence microscopy, 4Pi-, STED- and localization microscopy approaches, as well as (laterally) structured illumination microscopy (SIM). Here, we summarize the state of the art and discuss application perspectives for nuclear nanostructure analysis of spatially modulated illumination (SMI). SMI is a widefield-based approach to using axially structured illumination patterns to determine the axial extension (size) of small, optically isolated fluorescent objects between less than or equal to 200 nm and greater than or equal to 40 nm diameter with a precision down to the few nm range; in addition, it allows the axial positioning of such structures down to the 1 nm scale. Combined with SIM, a three-dimensional localization precision of less than or equal to 1 nm is expected to become feasible using fluorescence yields typical for single molecule localization microscopy applications. Together with its nanosizing capability, this may eventually be used to analyse macromolecular complexes and other nanostructures with a topological resolution, further narrowing the gap to Cryoelectron microscopy.

This article is part of the Theo Murphy meeting issue ‘Super-resolution structured illumination microscopy (part 2)’.

Super-resolution microscopy: a brief history and new avenues

Super-resolution microscopy (SRM) is a fast-developing field that encompasses fluorescence imaging techniques with the capability to resolve objects below the classical diffraction limit of optical resolution. Acknowledged with the Nobel prize in 2014, numerous SRM methods have meanwhile evolved and are being widely applied in biomedical research, all with specific strengths and shortcomings. While some techniques are capable of nanometre-scale molecular resolution, others are geared towards volumetric three-dimensional multi-colour or fast live-cell imaging. In this editorial review, we pick on the latest trends in the field. We start with a brief historical overview of both conceptual and commercial developments. Next, we highlight important parameters for imaging successfully with a particular super-resolution modality. Finally, we discuss the importance of reproducibility and quality control and the significance of open-source tools in microscopy. This article is part of the Theo Murphy meeting issue 'Super-resolution structured illumination microscopy (part 2)'.