[en] An experiment is reported intended for testing the possibility of achieving spatial resolution in the observation of a cylindrical plasma using a high quality objective, avoiding so the classical Abel inversion. The result shows that 90% of the light is issued from a zone covering one fourth of the radius of the cylinder for the 5770A Hg line. This result which may be acceptable for many experiments is not so good that coul be expected from the simplified calculations also reported

[en] A hard X-ray scanning microscope installed at the Hard X-ray Nanoprobe beamline of the National Synchrotron Light Source II has been designed, constructed and commissioned. The microscope relies on a compact, high stiffness, low heat dissipation approach and utilizes two types of nanofocusing optics. It is capable of imaging with ~15 nm × 15 nm spatial resolution using multilayer Laue lenses and 25 nm × 26 nm resolution using zone plates. Fluorescence, diffraction, absorption, differential phase contrast, ptychography and tomography are available as experimental techniques. The microscope is also equipped with a temperature regulation system which allows the temperature of a sample to be varied in the range between 90 K and 1000 K. The constructed instrument is open for general users and offers its capabilities to the material science, battery research and bioscience communities.

[en] Here we report the recent advances in the Neutron Microscope project at the Paul Scherrer Institut. We demonstrate the recent improvement on the capability of neutron imaging that allows us to acquire neutron images with isotropic spatial resolution of about 5 micrometres. (paper)

[en] Purpose: To develop and evaluate a new, pneumatically operated motion apparatus for the dynamic functional MR examination of the cervical spine. Materials and Methods: A metal-free, pneumatically operated motion apparatus for functional dynamic MR imaging of the cervical spine was developed with respect to the geometry of a short-bore, superconducting high-field MR system. The examination protocol included a T₂-weighted multi-slice turbospin echo sequence (T₂-TSE, TR/TE=2610/115, matrix 254/512) and a dynamic T₂-weighted single-shot sequence (T₂-TSE, TR/TE=1110/110, matrix 255/256, acquisition time 1 s) in a sagittal plane. In order to evaluate the new motion apparatus and the examination protocol, 10 healthy subjects and 10 patients were examined. Results: The new motion apparatus allowed us to perform a passive stepless inclination and reclination motion of the patient's cervical spine within the MR scanner without leaving the magnet bore. The maximum motion degrees of the cervical spine were within -35 C (reclination) and 30 C (inclination). Due to the T₂-contrast and the high spatial resolution of the dynamic sequence, the myelon, the surrounding cerebrospinal fluid and the discoligamental structures were imaged with a good contrast and allowed a sufficient evaluation of the cervical spinal channel in all functional positions. Conclusions: This new motion apparatus allows a standardized and stepless dynamic functional MR examination is a short-bore high-field MR scanner. By the use of fast T₂-weighted spin echo sequences it has been shown to be of high value for the evaluation of the cervical myelon, the anterior and posterior cerebrospinal fluid and the discoligamental structures. (orig.)

[en] Photoacoustic tomography (PAT) is an emerging and effective imaging technique, which offers high spatial resolution with high contrast. In particular, the acquired data is incomplete due to geometrical limitations or accelerating data acquisition by undersampling technology, thus some artifacts will be presented in the reconstructed image. To deal with limited-view PAT, we introduce a regularization scheme into PAT and propose a three-stage method. We first use the gradient descent method to obtain an initial solution, then project it onto a constrain set, and finally a proximal mapping scheme is used to further improve the reconstruction quality. Our simulation experiments on homogeneous medium are utilized to validate the effectiveness of the proposed method, and a discussion on the parameters of the proposed method is given. The experimental results reveal that the proposed method outperforms other classical methods, and it can further improve the reconstruction quality in terms of suppressing the noise and artifacts, and preserving the edge. (paper)

No abstract available

[en] In three-dimensional surface display, the grey-level values of the voxels on the surface of an object are not always constant. This fact means that the traditional grey-level gradients are not the exact representation of the surface normals. In this note the authors present an improved method of estimation of surface normal for 3D surface display. The new method calculates gradient at the location where the grey-level is equal to threshold value. Using this scheme, the gradients are estimated on an isogrey-level curve and are the exact surface normals. The images generated using this method show very fine details. The validity of the proposed scheme is illustrated with a number of examples from medical imaging. The results are compared to images rendered by the traditional grey-level gradient method. The proposed algorithm has advantages over the traditional method in improved estimation of surface normal and rendering of finer details. (Author)

No abstract available

[en] Ocular imaging technology that holds promise for both fundamental investigation and clinical detection of glaucoma is still a challenging research area. A direct view of the trabecular meshwork (TM) with high resolution is not generally possible because the iridocorneal angle region is obstructed by the sclera overlap. The best approach to observe the aqueous outflow system (AOS) is therefore to view from the opposite angle. In this research work, we developed two imaging systems for the high resolution ex vivo studies of the AOS inside porcine eye, based on a Gaussian illuminated and a digitally scanned Bessel–Gauss beam light sheet fluorescence configurations. The digitally scanned Bessel–Gauss beam is able to overcome the trade-off between the length and thickness of the Gaussian light sheet to give better imaging performance. It has adequate spatial resolution to resolve critical anatomical structures such as the TM, thereby enabling objective information about the AOS. This non-contact and non-invasive imaging methodology with excellent safety profile is expected to be well received by vision researchers and clinicians in the evaluation and management of glaucoma. (letter)

[en] Mathematical calculations have been performed to analyse how accurately the angle between objects, inclined in space, is reproduced on panoramic films. A marked tolerance against angle distortion was found. Angular measurements may be performed on correctly exposed panoramic films, and the values obtained are satisfactorily accurate for most clinical purposes. (Auth.)