The new X-ray/visible microscopy MAXWELL technique for fast three-dimensional nanoimaging with isotropic resolution.

Microscopy by Achromatic X-rays With Emission of Laminar Light (MAXWELL) is a new X-ray/visible technique with attractive characteristics including isotropic resolution in all directions, large-volume imaging and high throughput. An ultrathin, laminar X-ray beam produced by a Wolter type I mirror irradiates the sample stimulating the emission of visible light by scintillating nanoparticles, captured by an optical system. Three-dimensional (3D) images are obtained by scanning the specimen with respect to the laminar beam. We implemented and tested the technique with a high-brightness undulator at SPring-8, demonstrating its validity for a variety of specimens. This work was performed under the Synchrotrons for Neuroscience-an Asia-Pacific Strategic Enterprise (SYNAPSE) collaboration.

Batch and dynamic adsorption of lysozyme from chicken egg white on dye-affinity nanofiber membranes modified by ethylene diamine and chitosan.

Adsorption of lysozyme on the dye-affinity nanofiber membranes was investigated in batch and dynamic modes. The membrane matrix was made of electrospun polyacrylonitrile nanofibers that were grafted with ethylene diamine (EDA) and/or chitosan (CS) for the coupling of Reactive Blue 49 dye. The physicochemical properties of these dye-immobilized nanofiber membranes (P-EDA-Dye and P-CS-Dye) were characterized microscopically, spectroscopically and thermogravimetrically. The capacities of lysozyme adsorption by the dye-affinity nanofiber membranes were evaluated under various conditions, namely pH, dye immobilized density, and loading flow rate. The adsorption of lysozyme to the dye-affinity nanofiber membranes was well fitted by Langmuir isotherm and pseudo-second kinetic models. P-CS-Dye nanofiber membrane had a better performance in the dynamic adsorption of lysozyme from complex chicken egg white solution. It was observed that after five cycles of adsorption-desorption, the dye-affinity nanofiber membrane did not show a significant loss in its capacity for lysozyme adsorption. The robustness as well as high dynamic adsorption capability of P-CS-Dye nanofiber membrane are promising for the efficient recovery of lysozyme from complex feedstock via nanofiber membrane chromatography.

A miniature patient-mount navigation system for assisting needle placement in CT-guided intervention.

BACKGROUND: CT-guided intervention is routinely performed in an iterative fashion that often leads to lengthy operation and high X-ray exposure to patients. To streamline the workflow, we develop a patient-mount navigation system for assisting needle placement in CT-guided interventions. METHODS: The system comprises three components, a miniature patient-mount tracking unit, an auto-registered reference-frame unit and an intuitive image-processing unit. The system is operated like a virtual biplane fluoroscopy with augmented CT reconstructed images to streamline the conventional CT-guided intervention workflow. Surgery efficiency and safety can be increased, while radiation for patients and surgeons can be reduced. Two preclinical validations were conducted to evaluate the technical applicability and accuracy of the system. RESULTS: The results of the rigid physical phantom test showed a machine position error of 1.6 mm and a tilting error of 1.5°. The results of the deformable porcine phantom test showed the operation position error to be 3.6 mm and tilting error to be 2.9°. CONCLUSIONS: We concluded that the accuracy of our system is within the comparable range of the existing navigation systems.

A patient-mount navigated intervention system for spinal diseases and its clinical trial on percutaneous pulsed radiofrequency stimulation of dorsal root ganglion.

STUDY DESIGN: Development of a patient-mount navigated intervention (PaMNI) system for spinal diseases. An in vivo clinical human trial was conducted to validate this system. OBJECTIVE: To verify the feasibility of the PaMNI system with the clinical trial on percutaneous pulsed radiofrequency stimulation of dorsal root ganglion (PRF-DRG). SUMMARY OF BACKGROUND DATA: Two major image guiding techniques, i.e., computed tomography (CT)-guided and fluoro-guided, were used for spinal intervention. The CT-guided technique provides high spatial resolution, and is claimed to be more accurate than the fluoro-guided technique. Nevertheless, the CT-guided intervention usually reaches higher radiograph exposure than the fluoro-guided counterpart. Some navigated intervention systems were developed to reduce the radiation of CT-guided intervention. Nevertheless, these systems were not popularly used due to the longer operation time, a new protocol for surgeons, and the availability of such a system. METHODS: The PaMNI system includes 3 components, i.e., a patient-mount miniature tracking unit, an auto-registered reference frame unit, and a user-friendly image processing unit. The PRF-DRG treatment was conducted to find the clinical feasibility of this system. RESULTS: The in vivo clinical trial showed that the accuracy, visual analog scale evaluation after surgery, and radiograph exposure of the PaMNI-guided technique are comparable to the one of conventional fluoro-guided technique, while the operation time is increased by 5 minutes. CONCLUSION: Combining the virtues of fluoroscopy and CT-guided techniques, our navigation system is operated like a virtual fluoroscopy with augmented CT images. This system elevates the performance of CT-guided intervention and reduces surgeons' radiation exposure risk to a minimum, while keeping low radiation dose to patients like its fluoro-guided counterpart. The clinical trial of PRF-DRG treatment showed the clinical feasibility and efficacy of this system.

Feasibility study of using viscoplastic bone cement for vertebroplasty: an in vivo clinical trial and in vitro cadaveric biomechanical examination.

STUDY DESIGN: An in vivo clinical trial, and an in vitro cadaveric biomechanical and micromorphologic analysis. OBJECTIVE: To find the feasibility of using viscoplastic bone cement for vertebroplasty. SUMMARY OF BACKGROUND DATA: Vertebroplasty involved in bone cement reinforcement of fractured vertebra has shown promising clinical results. The most frequently observed complication of vertebroplasty is the cement leakage during surgery. Many methods were proposed and were successful at reducing the risk of leakage, such as creating a void within vertebra to reduce the injection pressure, increasing the cement viscosity to reduce the cement infiltration, etc. Nevertheless, a more cost-effective and safer surgery method is still the goal for many spine surgeons and researchers. METHODS: To deliver the viscoplastic bone cement into the vertebra, a unipedicular tract and a void in the vertebra was created using a curette. The viscoplastic bone cement was then delivered into the void piece by piece and tamped for compactness with a blunt end tool. For the in vitro biomechanical test, 7 thoracic vertebrae were used. The intact specimens were compressed to lose 25% of its intact height, and then augmented with viscoplastic bone cement. Postaugmentation CT scanning was taken to examine the cement distribution, leakage path, and cement filling ratio within the vertebra. Postaugmentation compression test was conducted to examine the vertebral strength and stiffness, and then compared with the intact ones. Finally, the vertebrae were cut into slices for micromorphologic analysis. RESULTS: The 6 in vivo clinical trials were all successfully operated with significant pain relief and showed no leakage during and after the surgery. The in vitro biomechanical test showed the cement augmentation significantly increased the vertebral strength (pre 3164 (229) N vs. post 3905 (484) N, P < 0.003), but tentatively decreased the vertebral stiffness (pre 1074 (74) N/mm vs. post 801 (370) N/mm, P = 0.081). The postaugmentation CT scanning showed the cement was well confined within the vertebra and the cement filling ratio was 21% (ranged from 15% to 29%). The depth that the viscoplastic bone cement infiltrated into the cancellous bone was 3.5 (0.6) mm, which is less than the depth [8.3 (2.2) mm, P < 0.001] of standard viscous bone cement vertebroplasty. CONCLUSION: Vertebroplasty using viscoplastic bone cement is clinically feasible and can effectively improve the vertebral strength and reduce the cement infiltration depth. The risk of cement leakage can also be decreased by using viscoplastic bone cement.