Axial Motion Compensation Of Optical Coherence Tomography With A Collaborative Medical Robot

This thesis presents an imaging tool consisting of an Optical Coherence Tomography (OCT) imaging system mounted on a collaborative robotic arm to enable axial motion compensation. Optical Coherence Tomography is a subsurface, high-resolution imaging modality used in neuroimaging to differentiate between pathological and non-pathological tissue. The motivation behind this project is to bring Optical Coherence Tomography to the operating room for neuroimaging to help with cancerous tissue differentiation and maximize the extent of tumor resection. However, neurosurgeons have expressed concern with respect to intracranial pressure (ICP) pulsation displacing the brain far off the optic axis of the imaging system so as to not be visible. The collaborative robotic arm compensates for sample motion along the optic axis using a Proportional controller to track the position of the peak intensity of the sample’s intensity profile, which generally corresponds to the sample surface. Collaborative robots have changed the robot industry paradigm becoming increasingly functional and safer than the previous generations of robotic arms. We present an OCT robot end-effector to test the feasibility of performing OCT imaging with the collaborative robot.

Axial Motion Compensation Of Optical Coherence Tomography With A Collaborative Medical Robot

This thesis presents an imaging tool consisting of an Optical Coherence Tomography (OCT) imaging system mounted on a collaborative robotic arm to enable axial motion compensation. Optical Coherence Tomography is a subsurface, high-resolution imaging modality used in neuroimaging to differentiate between pathological and non-pathological tissue. The motivation behind this project is to bring Optical Coherence Tomography to the operating room for neuroimaging to help with cancerous tissue differentiation and maximize the extent of tumor resection. However, neurosurgeons have expressed concern with respect to intracranial pressure (ICP) pulsation displacing the brain far off the optic axis of the imaging system so as to not be visible. The collaborative robotic arm compensates for sample motion along the optic axis using a Proportional controller to track the position of the peak intensity of the sample’s intensity profile, which generally corresponds to the sample surface. Collaborative robots have changed the robot industry paradigm becoming increasingly functional and safer than the previous generations of robotic arms. We present an OCT robot end-effector to test the feasibility of performing OCT imaging with the collaborative robot.

Supplemental Material: Long-term (7 Ma) strain fluctuations within the Dead Sea transform system from high-resolution U-Pb dating of a calcite vein

Appendix 1: Fluid inclusion data (1 file, 5 tabs); Appendix 2: U-Pb data table, including standards (and T-W plots); Appendix 3: GFS-5 optic axis stereoplots.

Supplemental Material: Long-term (7 Ma) strain fluctuations within the Dead Sea transform system from high-resolution U-Pb dating of a calcite vein

Appendix 1: Fluid inclusion data (1 file, 5 tabs); Appendix 2: U-Pb data table, including standards (and T-W plots); Appendix 3: GFS-5 optic axis stereoplots.

The Distribution of IOL Center and Its Relationship with Internal Ocular Objective Visual Quality in Cataract Patients

Background: To investigate the distribution of the center of the intraocular lens (IOL) after phacoemulsification, and to assess the correlation between the center of IOL and preoperative angle kappa, angle alpha, and objective internal visual quality, respectively, in cataract patients with monofocal and bifocal IOLs implantation. Methods: Prospective cross-section cases series. One hundred and thirty-seven eyes of 107 patients who underwent phacoemulsification were included. Preoperative angle kappa and alpha, postoperative internal ocular aberrations, internal objective visual quality, and the center of IOL relative to the visual axis (CIV) was evaluated using iTrace system. Independent sample t-tests and Pearson correlations were performed.Results: Locations of CIV were scattered in all directions centered on corneal light reflection for both C-Loop designed IOL and plate-haptic designed IOL. No correlations were found between CIV and preoperative angle kappa and alpha in both magnitude and orientation. No correlations were found between CIV and postoperative internal ocular aberrations (astigmatism, coma, and trefoil). In the bifocal IOLs group, the CIV was negatively correlated to the internal Strehl ratio at 3mm; however, it was not correlated to the Strehl ratio at 5mm. The magnitude of CIV was positively correlated to the length of the optic axis.Conclusions: CIV was not predictable according to angle kappa and alpha before cataract surgery. CIV was not related to internal ocular aberration, but large CIV may lead to light scattering due to steps between diffractive rings in patients with small pupil sizes. The magnitude of CIV may be greater in cataract patients with longer optic axis.Trial registration: retrospectively registered.

Phase imaging dislocations using diffracted beam interferometry

A phase imaging method that measures the phase shift existing at a dislocation’s core is described. The method uses the interference of two symmetrically diffracted beams on the optic axis by means of an electron biprism. Each diffracted beam carries half the phase of the dislocation core. When combined, the entire phase shift of the dislocation core is obtained.