On-shelf circulation of warm water toward the Totten Ice Shelf in East Antarctica.

The Totten Glacier in East Antarctica, with an ice volume equivalent to >3.5 m of global sea-level rise, is grounded below sea level and, therefore, vulnerable to ocean forcing. Here, we use bathymetric and oceanographic observations from previously unsampled parts of the Totten continental shelf to reveal on-shelf warm water pathways defined by deep topographic features. Access of warm water to the Totten Ice Shelf (TIS) cavity is facilitated by a deep shelf break, a broad and deep depression on the shelf, a cyclonic circulation that carries warm water to the inner shelf, and deep troughs that provide direct access to the TIS cavity. The temperature of the warmest water reaching the TIS cavity varies by ~0.8 °C on an interannual timescale. Numerical simulations constrained by the updated bathymetry demonstrate that the deep troughs play a critical role in regulating ocean heat transport to the TIS cavity and the subsequent basal melt of the ice shelf.

Effect of Anisotropic Hybridization in YbAlB_{4} Probed by Linear Dichroism in Core-Level Hard X-Ray Photoemission Spectroscopy.

We have probed the crystalline electric-field ground states of pure |J=7/2,J_{z}=±5/2⟩ as well as the anisotropic c-f hybridization in both valence fluctuating systems α- and ß-YbAlB_{4} by linear polarization dependence of angle-resolved core level photoemission spectroscopy. Interestingly, the small but distinct difference between α- and ß-YbAlB_{4} was found in the polar angle dependence of linear dichroism, indicating the difference in the anisotropy of c-f hybridization, which may be a key to understanding a heavy Fermi liquid state in α-YbAlB_{4} and a quantum critical state in ß-YbAlB_{4}.

Beam Characterization of 10-MV Photon Beam from Medical Linear Accelerator without Flattening Filter.

AIM: This work investigated the dosimetric properties of a 10-MV photon beam emitted from a medical linear accelerator (linac) with no flattening filter (FF). The aim of this study is to analyze the radiation fluence and energy emitted from the flattening filter free (FFF) linac using Monte Carlo (MC) simulations. MATERIALS AND METHODS: The FFF linac was created by removing the FF from a linac in clinical use. Measurements of the depth dose (DD) and the off-axis profile were performed using a three-dimensional water phantom with an ionization chamber. A MC simulation for a 10-MV photon beam from this FFF linac was performed using the BEAMnrc code. RESULTS: The off-axis profiles for the FFF linac exhibited a chevron-like distribution, and the dose outside the irradiation field was found to be lower for the FFF linac than for a linac with an FF (FF linac). The DD curves for the FFF linac included many contaminant electrons in the build-up region. CONCLUSION: Therefore, for clinical use, a metal filter is additionally required to reduce the effects of the electron contamination. The mean energy of the FFF linac was found to be lower than that of the FF linac owing to the absence of beam hardening caused by the FF.

[Foramen magunum meningioma presented as subarachnoid haemorrhage].

A 59-year-old woman was admitted with to our hospital with a sudden severe headache that had lasted for 5 days. Neck stiffness was present, but no other neurological deficits were present. Subarachnoid hemorrhage and intra-tumor hemorrhage were not noted on a head computed tomography (HCT). The patient's cerebrospinal fluid was xanthochromic. Magnetic resonance imaging (MRI) demonstrated a gadolinium-enhanced tumor with hemorrhagic changes around the foramen magnum. After conservative therapy, MRI showed a decrease in tumor size and a dural tail sign. This tumor was diagnosed as a hemorrhagic meningioma, and was resected with a posterior suboccipital approach. Histology confirmed that this tumor was a benign transitional meningioma with hemorrhagic change. This is a rare case involving benign meningioma onset by hemorrhagic change. Postoperative tumor recurrence was not present.

[Case of spontaneous cervical internal carotid artery dissection with embolic stroke after a job-change].

A 51 year old male was admitted to our hospital with sudden consciousness disturbance, global aphagia and right hemiparesis. Magnetic resonance imaging (MRI) revealed fresh infarctions in the territory of the left middle cerebral artery, and MR angiography (MRA) showed occlusion of the left carotid artery and the left middle cerebral artery. We started conservative therapy, including antiplatelet drug and blood pressure control. Three days later, cervical MRA revealed hematoma in the intracranial carotid wall of the petrous portion, leading to a diagnosis of spontaneous intracranial carotid artery dissection of the petrous portion. Two weeks after admission, MRA and angiography showed recanalization and pearl and string sign in the left petrous internal carotid artery. After that, the patient's neurological deficit improved, and the dissection also improved. Four months later, MR-angiography revealed an almost normalized condition.

[Pitfall in conservative therapy for working patients with brain ischemia].

A 59-year-old employed man was recommended to have surgical treatment for symptomatic left middle cerebral arterial stenosis. He refused surgical treatment for social reasons but was given conservative therapy for the prevention of the recurrence of cerebral infarction. Immediately after he retired, he had severe recurrent cerebral infarction with severe anemia and low blood pressure due to gastroduodenal ulcer bleeding. It was inferred from MRI findings that this recurrent cerebral infarction was related to a hemodynamic mechanism and mental stress due to the gastroduodenal ulcer. The influence of occupational mental stress has been reported to be a risk factor of gastroduodenal ulcer. The occupational situation of a patient should be an important factor in consideration of the prevention of cerebral apoplexy.

Phase I/II study of intraoperative radiotherapy for early breast cancer in Japan.

BACKGROUND: Intraoperative radiotherapy (IORT) is under evaluation in breast-conserving surgery. We have begun our study with the first step being a phase I-II study. This study was designed to identify the recommended dose and to test the feasibility of and tolerance to IORT in Japanese patients (UMIN000000918). METHODS: A phase I study was designed using a scheme of dose escalation from 19 to 20 to 21 Gy. We designed the phase II study to use the recommended dose. The primary endpoint was early toxicity. Secondary endpoints were efficacy for a long period and late toxicity. Inclusion criteria included the following: (1) T < 2.5 cm, (2) age >50 years, (3) surgical margin >1 cm, (4) intraoperative pathologically free margins, and (5) sentinel node negative. Partial resection was performed with at least a 1 cm margin around the tumor. Radiation was delivered directly to the mammary gland with the use of a Mobetron(®). The toxicity was evaluated with the Common Terminology Criteria for Adverse Events (CTCAE) v3.0. RESULTS: Nine patients were enrolled for the phase I study. All patients tolerated and we therefore recommend 21 Gy. The following 23 patients were enrolled in a phase II study and received 21 Gy. After a median follow-up of 26.0 months, their toxicities within 3 months included deep connective tissue fibrosis (G1 23/26, G2 2/26), hematoma (G1 9/26), infection in the musculoskeletal soft tissue (G1 4/26), and soft tissue necrosis (G2 3/26). There have been no local recurrences. CONCLUSIONS: The first group of Japanese female patients treated with IORT showed very good tolerability in the phase I/II study.

[Dosimetric perturbation due to scattered rays released by a gold marker used for tumor tracking in external radiotherapy].

Image-guided radiation therapy using a gold marker-based tumor tracking technique provides precise patient setup and monitoring. However, the marker consists of high-Z material, and the resulting scattered rays tend to have adverse effects on the dose distribution of radiotherapy. The purpose of this study was to evaluate the dosimetric perturbation due to the use of a gold marker for radiotherapy in the lungs. The relative dose distributions were compared with film measurement, Monte Carlo simulation, and XiO calculation with the multi grid superposition algorithm using two types of virtual lung phantoms, which were composed of tough water phantoms, tough lung phantoms, cork boards, and a 2.0-mm-diameter gold ball. No dose increase and decrease in the vicinity of the gold ball was seen in the XiO calculations, although it was seen in the film measurements and the Monte Carlo simulation. The dose perturbation due to a gold marker cannot be evaluated using XiO calculation with the superposition algorithm when the tumor is near a gold marker (especially within 0.5 cm). To rule out the presence of such dose perturbations due to a gold marker, the distance between the gold marker and the tumor must therefore be greater than 0.5 cm.

Dural attachment of intracranial meningiomas: evaluation with contrast-enhanced three-dimensional fast imaging with steady-state acquisition (FIESTA) at 3 T.

INTRODUCTION: The purpose of this study was to evaluate the role of contrast-enhanced fast imaging with steady-state acquisition (CE-FIESTA) for assessing whether dural attachment in intracranial meningiomas is adhesive or not by correlation with intraoperative findings. METHODS: Fourteen consecutive patients who were candidates for surgical treatment of meningiomas were prospectively analyzed with preoperative magnetic resonance imaging, including CE-FIESTA at 3 T. First, two neuroradiologists assessed several characteristics of the attachment of the meningioma to the dura mater or skull base on CE-FIESTA images. Second, the surgical findings of adhesion at the dural attachment of meningiomas were evaluated by two neurosurgeons. Finally, the CE-FIESTA findings were correlated with the surgical findings by one neurosurgeon and one neuroradiologist by consensus. RESULTS: CE-FIESTA clearly depicted a hypointense marginal line at the attachment site of the meningioma. When CE-FIESTA revealed smooth marginal lines or hyperintense zones along the marginal lines, tumors were detached easily from the dura mater. On the contrary, when CE-FIESTA showed an irregularity, such as partial disruption of the marginal lines, vessels, or bony hyperostosis, the tumors tended to adhere firmly to the dura mater, which was found to contain small vessels and fine fibrous tissues. CONCLUSIONS: There seems to be an excellent correlation between the characteristics of dural attachment of meningiomas on CE-FIESTA images and intraoperative findings. Therefore, for operative planning, CE-FIESTA may provide useful information regarding the adhesiveness of dural attachment.

Dose distribution near thin titanium plate for skull fixation irradiated by a 4-MV photon beam.

To investigate the effects of scattered radiation when a thin titanium plate (thickness, 0.05 cm) used for skull fixation in cerebral nerve surgery is irradiated by a 4-MV photon beam. We investigated the dose distribution of radiation inside a phantom that simulates a human head fitted with a thin titanium plate used for post-surgery skull fixation and compared the distribution data measured using detectors, obtained by Monte Carlo (MC) simulations, and calculated using a radiation treatment planning system (TPS). Simulations were shown to accurately represent measured values. The effects of scattered radiation produced by high-Z materials such as titanium are not sufficiently considered currently in TPS dose calculations. Our comparisons show that the dose distribution is affected by scattered radiation around a thin high-Z material. The depth dose is measured and calculated along the central beam axis inside a water phantom with thin titanium plates at various depths. The maximum relative differences between simulation and TPS results on the entrance and exit sides of the plate were 23.1% and - 12.7%, respectively. However, the depth doses do not change in regions deeper than the plate in water. Although titanium is a high-Z material, if the titanium plate used for skull fixation in cerebral nerve surgery is thin, there is a slight change in the dose distribution in regions away from the plate. In addition, we investigated the effects of variation of photon energies, sizes of radiation field and thickness of the plate. When the target to be irradiated is far from the thin titanium plate, the dose differs little from what it would be in the absence of a plate, though the dose escalation existed in front of the metal plate.

Efficacy of multi-staged surgery and adjuvant chemotherapy for successful treatment of atypical choroid plexus papilloma in an infant: case report.

A 12-month-old girl presented with a rare atypical choroid plexus papilloma manifesting as conscious disturbance and vomiting. Magnetic resonance (MR) imaging revealed a well-delineated 5 x 6-cm lobulate mass in the right lateral ventricle. Only partial removal of the tumor was performed because of excessive intraoperative hemorrhage at the first surgery. The histological diagnosis was atypical choroid plexus papilloma. To control the intraoperative hemorrhage, embolization of the feeding artery was performed before the second surgery, and the tumor was macroscopically totally removed. MR imaging disclosed a small residual tumor which showed relatively rapid growth. The patient underwent the third removal 5 months after the second surgery. Two months later, MR imaging showed a cystic lesion with a small nodule adjacent to the midbrain, indicating dissemination of the tumor. The lesion was successfully treated with chemotherapy. Atypical choroid plexus papilloma was recently defined in the classification of the World Health Organization, so clinical data based on these criteria are lacking to establish the therapeutic strategy. Total resection of atypical choroid plexus papilloma is the most reliable treatment at present. However, postoperative chemotherapy should be considered for recurrence or dissemination.

A phase I study of intraoperative radiotherapy for early breast cancer in Japan.

BACKGROUND: The present study was designed to identify the optimal intraoperative radiotherapy (IORT) dose for early breast cancer in Japanese women. METHODS: A phase I study was designed using a scheme of dose-escalation from 19, 20, and 21 Gy at 90% isodose. The primary endpoint was early toxicity. Secondary endpoints were efficacy for a long period and late toxicity. Inclusion criteria were as follows: (1) tumor size <2.5 cm, (2) age >50 years, (3) surgical margin >1 cm, (4) intraoperative pathologically free margins, (5) written informed consent. Exclusion criteria were (1) contraindication to radiation therapy, (2) extensive intraductal component. Partial resection was performed with at least a 1-cm margin around the tumor. Radiation was delivered directly to the mammary gland employing a MOBETRON device. Toxicity was evaluated with the Common Terminology Criteria for Adverse Events (CTCAE), version 3.0. RESULTS: From December 2007 to September 2008, 9 patients were enrolled in the study. The first three patients received a radiation dose of 19 Gy. Within 3 months toxicity in each case was deep connective tissue fibrosis (grade 1: 2/3, grade 2: 1/3). The next three patients received a dose of 20 Gy and had toxicities of deep connective tissue fibrosis (grade 1: 3/3), hematoma (grade 1: 2/3), infection in the musculoskeletal soft tissue (grade 1: 2/3), and soft tissue necrosis (grade 2: 1/3). The final three patients received a dose of 21 Gy and had toxicities of deep connective tissue fibrosis (grade 1: 2/3), hematoma (grade 1: 1/3), infection in the musculoskeletal soft tissue (grade 1: 1/3), and soft tissue necrosis (grade 2: 2/3). CONCLUSIONS: The IORT treatment was tolerated very well in Japanese women, and we now recommend the dose of 21 Gy.

Intrasyrinx hemorrhage associated with hemangioblastoma in epiconus.

BACKGROUND CONTEXT: Hemangioblastomas in the central nervous system are highly vascular lesions, but have low risk of hemorrhage. In spinal lesions, there are a few rare cases of intramedullary hemorrhages associated with hemangioblastoma, and their prognoses were very severe. PURPOSE: This is the first case of an intrasyrinx hemorrhage associated with hemangioblastoma in epiconus. We report this rare case and discuss the clinical manifestations of intrasyrinx hemorrhage caused by hemangioblastoma in epiconus. STUDY DESIGN: A case report. METHODS: This case report presents a 45-year-old woman with intrasyrinx hemorrhage caused by hemangioblastoma in epiconus. The patient presented with a sudden onset of burning bilateral leg pain and rectal/bladder dysfunction, indicating conus medullaris syndrome. Initial magnetic resonance imaging revealed an intramedullary nodular lesion in the epiconus and holocord syringomyelia. However, follow-up magnetic resonance imaging showed intramedullary hemorrhage. RESULTS: The patient underwent surgery, and an intrasyrinx hematoma was evacuated and the tumor was completely removed. Histological diagnosis was hemangioblastoma. Three months after surgery, the patient recovered from neurological deficits. CONCLUSIONS: We present this rare case, and emphasize hemangioblastoma as the differential diagnosis in hemorrhagic spinal lesion.

Neuronal damage in hydrocephalus and its restoration by shunt insertion in experimental hydrocephalus: a study involving the neurofilament-immunostaining method.

OBJECT: The morphological and functional impairments of neurons and their connections caused by hydrocephalus, and their restoration by ventricular shunt placement were investigated in experimental hydrocephalus by the immunostaining of neurofilaments, which constitute the major component of the neuronal cytoskeleton. METHODS: Progressive hydrocephalus was induced in 15 young mongrel dogs 1 to 2 months of age, 3 to 4 weeks after cisternal injection of kaolin. The dogs were divided into three groups of five animals each, a "preshunt," "post-shunt," and "nonshunt" group, depending on whether the hydrocephalic animals underwent a procedure to insert a ventriculoperitoneal shunt. Neurofilament, glial fibrillary acid protein (GFAP), and synaptophysin immunostaining were performed using samples of brain tissue from each hydrocephalic group and a fourth "control" group (five animals). In the cortex, morphological deformation and heterogeneous neurofilament immunoreactivity of the apical dendrites became pronounced in accordance with the progression of hydrocephalus (from the preshunt to the nonshunt group), and these changes remained after shunt insertion (postshunt group). In the periventricular white matter, swollen and fragmented axons increased in number along with hydrocephalic progression and were incompletely repaired by ventricular shunt placement. The GFAP-positive astrocytes observed around repaired axons in the postshunt group were seen more prominently than in the untreated hydrocephalic groups. In the internal capsule, fairly good recovery from axonal damage caused by the hydrocephalic condition was achieved by insertion of a ventricular shunt, compared with that seen in the periventricular white matter. CONCLUSIONS: Cytoskeletal damage of neurons in hydrocephalus and its incomplete restoration by shunt placement were most significant in the periventricular white matter. This finding may account for the impaired cognitive function seen in children who have shunts and an apparently reconstituted cerebral mantle; therefore, neuronal protection in the early hydrocephalic state should be considered.

[Gait analysis of idiopathic normal pressure hydrocephalus].

Normal pressure hydrocephalus (NPH) is a clinical syndrome associated with dementia, gait disturbance and urinary incontinence. Gait disturbance is usually the initial sign and most important symptom, but its objective evaluation has not been established. We analyzed the gait of an idiopathic NPH before and after ventricular shunting with the gait analysis system. Before shunting, the stride was short and irregular, and the truncal movement was unsteady. Three-dimensional patterns of angular relationships between 3 joints, namely the ankle, knee and hip were small and irregular. The vector profile of floor reaction force showed a monophasic pattern with absence of the peak at toe-off. After shunting, the step enlarged and the truncal movement was steady. The three-dimensional patterns of angular relationships between the 3 joints were nearly normalized. The vector profile of floor reaction force showed an appearance of the peak at toe-off, which formed a biphasic pattern, similar to the pattern of a normal person. The gait analysis is a useful method to evaluate gait disturbance in idiopathic NPH.

[Measurement of the mean energy of the off-axis incident electron without the beam guide: using a scintillating fiber beam-energy monitor for electron beam therapy].

In the case of total skin electron therapy without the beam guide, the electron beam is scattered just outside the gantry exit, dose uniformity in the field is broken, and dose is spread outside the light field. The aims of this study were to measure the mean energy of the off-axis incident electron beam without the beam guide and to establish a reference for the clinical situation. For the measurement, a 4 MeV electron beam was selected among several energies from the linear accelerator. A scintillating fiber beam energy monitor measured the mean energy of the incident electron beam. This energy monitor is a small, light-weight piece of equipment composed of a wedge absorber, scintillation fiber, and photodiode. We found the relationship between electron energy and the indicated value of the energy monitor by means of the estimation of correction factors for five different kinds of electron energy. The preferable linear correlation of 0.997 of the coefficient of determination (R(2)) was obtained. From the results of measurement at each point, those variations due to the off-axial distance were about 5% within the measured area. It was assumed that the energy did not change rapidly beyond the light field. Clinically, this amount of variation in energy may not cause any problem.