Optic Radiation

2019 ◽  
pp. 31-32
Author(s):  
Xuyang Liu ◽  
Jia Ma ◽  
Ningli Wang
Keyword(s):  
Optic Radiation

scholarly journals Linking optic radiation volume to visual perception in schizophrenia and bipolar disorder

2017 ◽  
Vol 190 ◽  
pp. 102-106 ◽  
Author(s):  
Eric A. Reavis ◽  
Junghee Lee ◽  
Jonathan K. Wynn ◽  
Katherine L. Narr ◽  
Stephanie N. Njau ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Visual Perception ◽  
Optic Radiation

Cerebral Microinfarcts in Primary Open-Angle Glaucoma Correlated With DTI-Derived Integrity of Optic Radiation

2014 ◽  
Vol 55 (11) ◽  
pp. 7241 ◽  
Author(s):  
Johannes Schoemann ◽  
Tobias Engelhorn ◽  
Simone Waerntges ◽  
Arnd Doerfler ◽  
Ahmed El-Rafei ◽  
...  
Keyword(s):  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Optic Radiation ◽  
Open Angle

Direct electrical stimulation of the optic radiation in patients with covered eyes

2014 ◽  
Vol 37 (3) ◽  
pp. 527-533 ◽  
Author(s):  
Andrej Šteňo ◽  
Vladimír Hollý ◽  
Martin Fabian ◽  
Matúš Kuniak ◽  
Gabriela Timárová ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Direct Electrical Stimulation ◽  
Optic Radiation ◽  
Stimulation Of

Diffusion tensor tractography of the temporal stem on the inferior limiting sulcus

2008 ◽  
Vol 108 (4) ◽  
pp. 775-781 ◽  
Author(s):  
Feng Wang ◽  
Tao Sun ◽  
Xing-Gang Li ◽  
Na-Jia Liu
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Anterior Commissure ◽  
Region Of Interest ◽  
Diffusion Tensor Tractography ◽  
Optic Radiation ◽  
Uncinate Fasciculus ◽  
White Matter Tracts ◽  
Temporal Horn ◽  
Temporal Stem

Object The aim of this study was to use diffusion tensor tractography (DTT) to define the 3D relationships of the uncinate fasciculus, anterior commissure, inferior occipitofrontal fasciculus, inferior thalamic peduncle, and optic radiation and to determine the positioning landmarks of these white matter tracts. Methods The anatomy was studied in 10 adult human brain specimens. Brain DTT was performed in 10 healthy volunteers. Diffusion tensor tractography images of the white matter tracts in the temporal stem were obtained using the simple single region of interest (ROI) and multi-ROIs based on the anatomical knowledge. Results The posteroinferior insular point is the anterior extremity of intersection of the Heschl gyrus and the inferior limiting sulcus. On the inferior limiting sulcus, this point is the posterior limit of the optic radiation, and the temporal stem begins at the limen insulae and ends at the posteroinferior insular point. The distance from the limen insulae to the tip of the temporal horn is just one third the length of the temporal stem. The uncinate fasciculus comprises the core of the anterior temporal stem, behind which the anterior commissure and the inferior thalamic peduncle are located, and they occupy the anterior third of the temporal stem. The inferior occipitofrontal fasciculus passes through the entire temporal stem. The most anterior extent of the Meyer loop is located between the anterior tip of the temporal horn and the limen insulae. Most of the optic radiation crosses the postmedian two thirds of the temporal stem. Conclusions On the inferior limiting sulcus, the posteroinferior insular point is a reliable landmark of the posterior limit of the optic radiations. The limen insulae, anterior tip of the temporal horn, and posteroinferior insular point may be used to localize the white matter fibers of the temporal stem in analyzing magnetic resonance imaging or during surgery.

Fiber optic radiation dosimetry for medical applications

1990 ◽  
Author(s):  
Harald Bueker ◽  
Friedrich W. Haesing ◽  
S. Nicolai ◽  
B. Wolters
Keyword(s):  
Radiation Dosimetry ◽  
Fiber Optic ◽  
Medical Applications ◽  
Optic Radiation

scholarly journals Measurement of Gamma-Rays Induced Luminescence Generated in a Sapphire Based Fiber-Optic Radiation Sensor

2016 ◽  
Vol 04 (08) ◽  
pp. 1503-1506 ◽  
Author(s):  
Young Beom Song ◽  
Kyoung Won Jang ◽  
Hye Jin Kim ◽  
Dong Eun Lee ◽  
Mingeon Kim ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Fiber Optic ◽  
Optic Radiation ◽  
Radiation Sensor

scholarly journals Gamma-ray Spectroscopy Using Inorganic Scintillator Coated with Reduced Graphene Oxide in Fiber-Optic Radiation Sensor

Photonics ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 543
Author(s):  
Jin Ho Kim ◽  
Seunghyeon Kim ◽  
Siwon Song ◽  
Taeseob Lim ◽  
Jae Hyung Park ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Gamma Ray ◽  
Fiber Optic ◽  
Energy Spectra ◽  
Optic Radiation ◽  
Radiation Sensor ◽  
Reduced Graphene ◽  
Gamma Ray Spectroscopy ◽  
Inorganic Scintillators

In this study, we developed a remote gamma-ray spectroscopy system based on a fiber-optic radiation sensor (FORS) that is composed of an inorganic scintillator coated with reduced graphene oxide (RGO) and a plastic optical fiber (POF). As a preliminary experiment, we measured the transmitted light intensities using RGO membranes of different thicknesses with different wavelengths of emitted light. To evaluate the FORS performance, we determined the optimal thickness of the RGO membrane and measured the amounts of scintillating light and gamma energy spectra using radioactive isotopes such as 60Co and 137Cs. The amounts of scintillating light from the RGO-coated inorganic scintillators increased, and the energy resolutions of the gamma-ray spectra were enhanced. In addition, the gamma-ray energy spectra were measured using different types of RGO-coated inorganic scintillators depending on the lengths of the POFs for remote gamma-ray spectroscopy. It was expected that inorganic scintillators coated with RGO in FORS can deliver improved performance, such as increments of scintillating light and energy resolution in gamma-ray spectroscopy, and they can be used to identify nuclides remotely in various nuclear facilities.

Optic radiation tractography integrated into simulated treatment planning for Gamma Knife surgery

2007 ◽  
Vol 107 (4) ◽  
pp. 721-726 ◽  
Author(s):  
Keisuke Maruyama ◽  
Kyousuke Kamada ◽  
Masahiro Shin ◽  
Daisuke Itoh ◽  
Yoshitaka Masutani ◽  
...  
Keyword(s):  
Visual Field ◽  
Treatment Planning ◽  
Gamma Knife ◽  
Diffusion Tensor ◽  
Maximum Dose ◽  
Gamma Knife Surgery ◽  
Optic Radiation ◽  
Imaging Studies ◽  
Visual Field Deficits ◽  
Neurological Change

Object No definitive method of preventing visual field deficits after stereotactic radiosurgery for lesions near the optic radiation (OR) has been available so far. The authors report the results of integrating OR tractography based on diffusion tensor (DT) magnetic resonance imaging into simulated treatment planning for Gamma Knife surgery (GKS). Methods Data from imaging studies performed in 10 patients who underwent GKS for treatment of arteriovenous malformations (AVMs) located adjacent to the OR were used for the simulated treatment planning. Diffusion tensor images performed without the patient's head being secured by a stereotactic frame were used for DT tractography, and the OR was visualized by means of software developed by the authors. Data from stereotactic 3D imaging studies performed after frame fixation were coregistered with the data from DT tractography. The combined images were transferred to a GKS treatment-planning workstation. Delivered doses and distances between the treated lesions and the OR were analyzed and correlated with posttreatment neurological changes. Results In patients presenting with migraine with visual aura or occipital lobe epilepsy, the OR was located within 11 mm from AVMs. In a patient who developed new quadrantanopia after GKS, the OR had received 32 Gy. A maximum dose to the OR of less than 12 Gy did not cause new visual field deficits. A maximum dose to the OR of 8 Gy or more was significantly related to neurological change (p < 0.05), including visual field deficits and development or improvement of migraine. Conclusions Integration of OR tractography into GKS represents a promising tool for preventing GKS-induced visual disturbances and headaches. Single-session irradiation at a dose of 8 Gy or more was associated with neurological change.

scholarly journals Single-unit recording from antidromically activated optic radiation neurones

1962 ◽  
Vol 162 (3) ◽  
pp. 432-450 ◽  
Author(s):  
P. O. Bishop ◽  
W. Burke ◽  
R. Davis
Keyword(s):  
Single Unit ◽  
Single Unit Recording ◽  
Optic Radiation ◽  
Unit Recording

scholarly journals Stereotactic diffusion tensor imaging tractography for Gamma Knife radiosurgery

2016 ◽  
Vol 125 (Supplement_1) ◽  
pp. 139-146 ◽  
Author(s):  
Cormac G. Gavin ◽  
H. Ian Sabin
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Stereotactic Radiosurgery ◽  
Treatment Planning ◽  
Vestibular Schwannoma ◽  
Diffusion Tensor ◽  
Gamma Knife Radiosurgery ◽  
Optic Radiation ◽  
Arcuate Fasciculus ◽  
Stereotactic Frame

OBJECTIVEThe integration of modern neuroimaging into treatment planning has increased the therapeutic potential and safety of stereotactic radiosurgery. The authors report their method of integrating stereotactic diffusion tensor imaging (DTI) tractography into conventional treatment planning for Gamma Knife radiosurgery (GKRS). The aim of this study was to demonstrate the feasibility of this technique and to address some of the technical limitations of previously reported techniques.METHODSTwenty patients who underwent GKRS composed the study cohort. They consisted of 1 initial test case (a patient with a vestibular schwannoma), 5 patients with arteriovenous malformations, 9 patients with cerebral metastases, 1 patient with parasagittal meningioma, and 4 patients with vestibular schwannoma. DT images were obtained at the time of standard GKRS protocol MRI (T1 and T2 weighted) for treatment, with the patient's head secured by a Leksell stereotactic frame. All studies were performed using a 1.5-T magnet with a single-channel head coil. DTI was performed with diffusion gradients in 32 directions and coregistered with the volumetric T1-weighted study. DTI postprocessing by means of commercially available software allowed tensor computation and the creation of directionally encoded color–, apparent diffusion coefficient–, and fractional anisotropy–mapped sequences. In addition, the software allowed visualized critical tracts to be exported as a structural volume and integrated into GammaPlan as an “organ at risk” during shot planning. Combined images were transferred to GammaPlan and integrated into treatment planning.RESULTSStereotactic DT images were successfully acquired in all patients, with generation of correct directionally encoded color images. Tract generation with the software was straightforward and reproducible, particularly for axial tracts such as the optic radiation and the arcuate fasciculus. Corticospinal tract visualization was hampered by some artifacts from the base of the stereotactic frame, but this was overcome by a combination of frame/MRI volume adjustment and DTI seeding parameters. Coregistration of the DTI series with the T1-weighted treatment volume at the time of imaging was essential for the generation of correct tensor data. All patients with the exception of the vestibular schwannoma cases had treatment pathology in the vicinity of eloquent tracts and/or the cortex. No new neurological deficits due to radiation were recorded at the short-term follow-up.CONCLUSIONSRecent reports in the medical literature have suggested that white matter tracts (particularly the optic radiation and arcuate fasciculus) are more vulnerable to radiation during stereotactic radiosurgery than previously thought. Integration of stereotactic tractography into GKRS represents a promising tool for preventing GKRS complications by reduction in radiation doses to functional organs at risk, including critical cortical areas and subcortical white matter tracts.

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