Endoscopic Endonasal Approach for Optic Canal Dural Metastasis in a Patient with Progressive Visual Dysfunction: A Case Report.

To improve optic nerve function in a patient with progressive visual dysfunction, performing early decompressive and debulking surgery for a metastatic tumor located in the optic canal is essential. The endoscopic endonasal approach could be a practical and effective alternative for lesions in the inferomedial part of the optic canal. A 66-year-old man with a right visual eye field deficit had multiple lesions in the pineal gland, occipital lobe, and right inferomedial optic canal. The optic nerve was distorted by a tumor compressing against the falciform ligament. Although a systemic examination suggested the presence of primary lung cancer, the patient only complained of progressive visual impairment in the right eye. We planned surgery with endoscopic transethmoidal and transsphenoidal approaches to restore visual function and make a pathological diagnosis. During the procedure, we drilled the sella floor, tuberculum sellae, and optic canal and successfully removed the tumor underneath the dura mater. The patient's visual function improved rapidly following surgery, and no complications were observed, such as cerebrospinal fluid leakage. After confirming the pathological diagnosis, the patient subsequently received whole-brain radiotherapy. The endoscopic endonasal skull base approach to the optic canal region could be a practical alternative for treating symptomatic metastatic tumors.

Double-multilayer monochromators for high-energy and large-field X-ray imaging applications with intense pink beams at SPring-8 BL20B2.

In this study, double-multilayer monochromators that generate intense, high-energy, pink X-ray beams are designed, installed and evaluated at the SPring-8 medium-length (215 m) bending-magnet beamline BL20B2 for imaging applications. Two pairs of W/B4C multilayer mirrors are designed to utilize photon energies of 110 keV and 40 keV with bandwidths of 0.8% and 4.8%, respectively, which are more than 100 times larger when compared with the Si double-crystal monochromator (DCM) with a bandwidth of less than 0.01%. At an experimental hutch located 210 m away from the source, a large and uniform beam of size 14 mm (V) × 300 mm (H) [21 mm (V) × 300 mm (H)] was generated with a high flux density of 1.6 × 109 photons s-1 mm-2 (6.9 × 1010 photons s-1 mm-2) at 110 keV (40 keV), which marked a 300 (190) times increase in the photon flux when compared with a DCM with Si 511 (111) diffraction. The intense pink beams facilitate advanced X-ray imaging for large-sized objects such as fossils, rocks, organs and electronic devices with high speed and high spatial resolution.