Results from a synthetic model of the ITER XRCS-Core diagnostic based on high-fidelity x-ray ray tracing.

A high-fidelity synthetic diagnostic has been developed for the ITER core x-ray crystal spectrometer diagnostic based on x-ray ray tracing. This synthetic diagnostic has been used to model expected performance of the diagnostic, to aid in diagnostic design, and to develop engineering tolerances. The synthetic model is based on x-ray ray tracing using the recently developed xicsrt ray tracing code and includes a fully three-dimensional representation of the diagnostic based on the computer aided design. The modeled components are: plasma geometry and emission profiles, highly oriented pyrolytic graphite pre-reflectors, spherically bent crystals, and pixelated x-ray detectors. Plasma emission profiles have been calculated for Xe44+, Xe47+, and Xe51+, based on an ITER operational scenario available through the Integrated Modelling & Analysis Suite database, and modeled within the ray tracing code as a volumetric x-ray source; the shape of the plasma source is determined by equilibrium geometry and an appropriate wavelength distribution to match the expected ion temperature profile. All individual components of the x-ray optical system have been modeled with high-fidelity producing a synthetic detector image that is expected to closely match what will be seen in the final as-built system. Particular care is taken to maintain preservation of photon statistics throughout the ray tracing allowing for quantitative estimates of diagnostic performance.

Beamline simulations using monochromators with high d-spacing crystals.

Monochromators for synchrotron radiation beamlines typically use perfect crystals for the hard X-ray regime and gratings for soft X-rays. There is an intermediate range, typically 1-3 keV (tender X-rays), which common perfect crystals have difficulties covering and gratings have low efficiency, although some less common crystals with high d-spacing could be suitable. To evaluate the suitability of these crystals for a particular beamline, it is useful to evaluate the crystals' performance using tools such as ray-tracing. However, simulations for double-crystal monochromators are only available for the most used crystals such as Si, Ge or diamond. Here, an upgrade of the SHADOW ray-tracing code and complementary tools in the OASYS suite are presented to simulate high d-spacing crystals with arbitrary, and sometimes complex, structures such as beryl, YB66, muscovite, etc. Isotropic and anisotropic temperature factors are also considered. The YB66 crystal with 1936 atomic sites in the unit cell is simulated, and its applicability for tender X-ray monochromators is discussed in the context of new low-emittance storage rings.

Calcitonin gene-related peptide in migraine: from pathophysiology to treatment.

INTRODUCTION: It has been observed in recent years that levels of such molecules as calcitonin gene-related peptide (CGRP) and, to a lesser extent, the pituitary adenylate cyclase-activating peptide are elevated during migraine attacks and in chronic migraine, both in the cerebrospinal fluid and in the serum. Pharmacological reduction of these proteins is clinically significant, with an improvement in patients' migraines. It therefore seems logical that one of the main lines of migraine research should be based on the role of CGRP in the pathophysiology of this entity. DEVELOPMENT: The Spanish Society of Neurology's Headache Study Group decided to draft this document in order to address the evidence on such important issues as the role of CGRP in the pathophysiology of migraine and the mechanism of action of monoclonal antibodies and gepants; and to critically analyse the results of different studies and the profile of patients eligible for treatment with monoclonal antibodies, and the impact in terms of pharmacoeconomics. CONCLUSIONS: The clinical development of gepants, which are CGRP antagonists, for the acute treatment of migraine attacks, and CGRP ligand and receptor monoclonal antibodies offer promising results for these patients.

1st Post-European Headache Federation Meeting: a review of the latest developments presented at the 2020 European Headache Federation Congress. / I Reunión Post-European Headache Federation: revisión de las novedades presentadas en el Congreso de la European Headache Federation de 2020.

INTRODUCTION: After the European Headache Federation (EHF) Congress, renowned Spanish neurologists specialised in migraine presented the most significant latest developments in research in this field at the Post-EHF Meeting. DEVELOPMENT: The main data presented concerning the treatment of chronic and episodic migraine were addressed, with attention paid more specifically to those related to preventive treatments and real-life experience in the management of the disease. An important review was carried out of the new therapeutic targets and the possibilities they offer in terms of understanding the pathophysiology of migraine and its treatment. An update was also presented of the latest developments in the treatment of migraine with fremanezumab, a monoclonal antibody recently authorised by the European Medicines Agency. Participants were also given an update on the latest developments in basic research on the pathology, as well as an overview of the symptoms of migraine and COVID-19. Finally, the repercussions of migraine in terms of its burden on the care and economic resources of the health system were addressed, along with its impact on society. CONCLUSIONS: The meeting summarised the content presented at the 14th EHF Congress, which took place in late June/early July 2020.

TITLE: I Reunión Post-European Headache Federation: revisión de las novedades presentadas en el Congreso de la European Headache Federation de 2020.Introducción. Tras la celebración del congreso de la European Headache Federation (EHF), reconocidos neurólogos españoles expertos en el tratamiento de la migraña expusieron en la Reunión Post-EHF las principales novedades presentadas en el congreso y relacionadas con ese ámbito. Desarrollo. Se abordan los principales datos presentados relacionados con el tratamiento de la migraña crónica y episódica; concretamente, los relacionados con los tratamientos preventivos y la experiencia en vida real en el manejo de la enfermedad. Se hizo una importante revisión de las nuevas dianas terapéuticas y las posibilidades que ofrecen en cuanto al conocimiento de la fisiopatología de la migraña y su tratamiento. Asimismo, se hizo una actualización de las novedades presentadas en el tratamiento de la migraña con fremanezumab, anticuerpo monoclonal recientemente autorizado por la Agencia Europea de Medicamentos. Se hizo una actualización de las novedades en investigación básica en la patología, así como una relación de los síntomas de migraña y COVID-19. Finalmente, se abordaron las implicaciones de la migraña en la carga sanitaria asistencial y económica, y su impacto en la sociedad. Conclusiones. En la reunión se hizo un resumen del contenido presentado en el 14 Congreso de la EHF, que tuvo lugar a finales de junio y principios de julio de 2020.

Document of revision and updating of medication overuse headache (MOH). / Documento de revisión y actualización de la cefalea por uso excesivo de medicación (CUEM).

INTRODUCTION: Medication overuse headache is a secondary headache in which the regular or frequent use of analgesics can increase the frequency of the episodes, causing the transition from episodic to chronic headache. The prevalence of medication overuse headache is approximately 1-2%, with higher rates among women aged 30-50 years and with comorbid psychiatric disorders such as depression or anxiety, or other chronic pain disorders. It is important to be familiar with the management of this disease. To this end, the Spanish Society of Neurology's Headache Study Group has prepared a consensus document addressing this disorder. DEVELOPMENT: These guidelines were prepared by a group of neurologists specialising in headache after a systematic literature review and provides consensus recommendations on the proper management and treatment of medication overuse headache. The treatment of medication overuse headache is often complex, and is based on 4 fundamental pillars: education and information about the condition, preventive treatment, discontinuation of the drug being overused, and treatment for withdrawal symptoms. Follow-up of patients at risk of recurrence is important. CONCLUSIONS: We hope that this document will be useful in daily clinical practice and that it will update and improve understanding of medication overuse headache management.

Evaluation of the concomitant use of oral preventive treatments and onabotulinumtoxinA in chronic migraine: the PREVENBOX study.

BACKGROUND AND PURPOSE: OnabotulinumtoxinA is an effective preventive treatment for chronic migraine (CM). In CM, in addition to a reduction in headache frequency, a decreased reliance on oral prophylactics is also indicative of treatment effectiveness. This study aimed to quantify the change in the use of oral prophylactics after treatment with onabotulinumtoxinA in patients with CM. METHODS: This was a retrospective, multicentric, cross-sectional study. Patients with CM (International Classification of Headache Disorders-3beta) that had been treated with onabotulinumtoxinA were enrolled consecutively. We collected parameters related to each patient's pre-treatment situation, as well as their current situation, focusing on frequency and intensity of migraine, number of oral prophylactics and the respective cycle of onabotulinumtoxinA. Univariate and logistic regression analyses were performed. RESULTS: We included 542 patients, 90.0% of whom were taking oral preventive treatments. During treatment with onabotulinumtoxinA, 47.8% withdrew at least one prophylactic and 41.6% stopped using oral prophylactics altogether. Factors associated with a reduction or cessation of oral prophylactics were >50% improvement in frequency and intensity, remission to episodic migraine, use of topiramate as an initial treatment, increased number of infiltrations and shorter chronification period (P < 0.05). The multivariate analysis showed that a chronification period <20 months, more than five cycles of onabotulinumtoxinA, >50% improvement in pain intensity and topiramate as an initial treatment were predictors of a reduction in oral prophylactics (area under the curve, 70.3%; P < 0.001). CONCLUSIONS: Our study demonstrated the efficacy and safety of onabotulinumtoxinA. This treatment reduced the use of oral prophylactics. Withdrawal of oral prophylactics was most likely to occur after five cycles of treatment.

Evidence of and experience with the use of onabotulinumtoxinA in trigeminal neuralgia and primary headaches other than chronic migraine. / Evidencia y experiencia del uso de onabotulinumtoxinA en neuralgia del trigémino y cefaleas primarias distintas de la migraña crónica.

INTRODUCTION: In the field of headaches, onabotulinumtoxinA (onabotA) is well established as a treatment for chronic migraine (CM). In recent years, it has been used increasingly to treat other primary headaches (high-frequency episodic migraine, trigeminal-autonomic cephalalgias, nummular headache) and trigeminal neuralgia. As this treatment will progressively be incorporated in the management of these patients, we consider it necessary to reflect, with a fundamentally practical approach, on the possible indications of onabotA, beyond CM, as well as its administration protocol, which will differ according to the type of headache and/or neuralgia. DEVELOPMENT: This consensus document was drafted based on a thorough review and analysis of the existing literature and our own clinical experience. The aim of the document is to serve as guidelines for professionals administering onabotA treatment. The first part will address onabotA's mechanism of action, and reasons for its use in other types of headache, from a physiopathological and clinical perspective. In the second part, we will review the available evidence and studies published in recent years. We will add an "expert recommendation" based on our own clinical experience, showing the best patient profile for this treatment and the most adequate dose and administration protocol. CONCLUSION: Treatment with onabotA should always be individualised and considered in selected patients who have not responded to conventional therapy.

Calcitonin gene-related peptide in migraine: from pathophysiology to treatment. / CGRP en migraña: de la fisiopatología a la terapéutica.

INTRODUCTION: It has been observed in recent years that levels of such molecules as calcitonin gene-related peptide (CGRP) and, to a lesser extent, the pituitary adenylate cyclase-activating peptide are elevated during migraine attacks and in chronic migraine, both in the cerebrospinal fluid and in the serum. Pharmacological reduction of these proteins is clinically significant, with an improvement in patients' migraines. It therefore seems logical that one of the main lines of migraine research should be based on the role of CGRP in the pathophysiology of this entity. DEVELOPMENT: The Spanish Society of Neurology's Headache Study Group decided to draft this document in order to address the evidence on such important issues as the role of CGRP in the pathophysiology of migraine and the mechanism of action of monoclonal antibodies and gepants; and to critically analyse the results of different studies and the profile of patients eligible for treatment with monoclonal antibodies, and the impact in terms of pharmacoeconomics. CONCLUSIONS: The clinical development of gepants, which are CGRP antagonists, for the acute treatment of migraine attacks, and CGRP ligand and receptor monoclonal antibodies offer promising results for these patients.

Evidence and experience with onabotulinumtoxinA in chronic migraine: Recommendations for daily clinical practice. / Evidencia y experiencia de bótox en migraña crónica: Recomendaciones para la práctica clínica diaria.

OnabotulinumtoxinA has been demonstrated to be effective as a preventive treatment in patients with chronic migraine (CM). Five years after the approval of onabotulinumtoxinA in Spain, the Headache Study Group of the Spanish Society of Neurology considered it worthwhile to gather a group of experts in treating patients with CM in order to draw up, based on current evidence and our own experience, a series of guidelines aimed at facilitating the use of the drug in daily clinical practice. For this purpose, we posed 12 questions that we ask ourselves as doctors, and which we are also asked by our patients. Each author responded to one question, and the document was then reviewed by everyone. We hope that this review will constitute a practical tool to help neurologists treating patients with CM.

Application of spatially resolved high resolution crystal spectrometry to inertial confinement fusion plasmas.

High resolution (λ∕Δλ ∼ 10 000) 1D imaging x-ray spectroscopy using a spherically bent crystal and a 2D hybrid pixel array detector is used world wide for Doppler measurements of ion-temperature and plasma flow-velocity profiles in magnetic confinement fusion plasmas. Meter sized plasmas are diagnosed with cm spatial resolution and 10 ms time resolution. This concept can also be used as a diagnostic of small sources, such as inertial confinement fusion plasmas and targets on x-ray light source beam lines, with spatial resolution of micrometers, as demonstrated by laboratory experiments using a 250-µm (55)Fe source, and by ray-tracing calculations. Throughput calculations agree with measurements, and predict detector counts in the range 10(-8)-10(-6) times source x-rays, depending on crystal reflectivity and spectrometer geometry. Results of the lab demonstrations, application of the technique to the National Ignition Facility (NIF), and predictions of performance on NIF will be presented.

Neurophysiological tests and neuroimaging procedures in non-acute headache (2nd edition).

BACKGROUND AND PURPOSE: A large number of instrumental investigations are used in patients with non-acute headache in both research and clinical fields. Although the literature has shown that most of these tools contributed greatly to increasing understanding of the pathogenesis of primary headache, they are of little or no value in the clinical setting. METHODS: This paper provides an update of the 2004 EFNS guidelines and recommendations for the use of neurophysiological tools and neuroimaging procedures in non-acute headache (first edition). Even though the period since the publication of the first edition has seen an increase in the number of published papers dealing with this topic, the updated guidelines contain only minimal changes in the levels of evidence and grades of recommendation. RESULTS: (i) Interictal EEG is not routinely indicated in the diagnostic evaluation of patients with headache. Interictal EEG is, however, indicated if the clinical history suggests a possible diagnosis of epilepsy (differential diagnosis). Ictal EEG could be useful in certain patients suffering from hemiplegic or basilar migraine. (ii) Recording evoked potentials is not recommended for the diagnosis of headache disorders. (iii) There is no evidence warranting recommendation of reflex responses or autonomic tests for the routine clinical examination of patients with headache. (iv) Manual palpation of pericranial muscles, with standardized palpation pressure, can be recommended for subdividing patient groups but not for diagnosis. Pain threshold measurements and EMG are not recommended as clinical diagnostic tests. (v) In adult and pediatric patients with migraine, with no recent change in attack pattern, no history of seizures, and no other focal neurological symptoms or signs, the routine use of neuroimaging is not warranted. In patients with trigeminal autonomic cephalalgia, neuroimaging should be carefully considered and may necessitate additional scanning of intracranial/cervical vasculature and/or the sellar/orbital/(para)nasal region. In patients with atypical headache patterns, a history of seizures and/or focal neurological symptoms or signs, MRI may be indicated. (vi) If attacks can be fully accounted for by the standard headache classification (IHS), a PET or SPECT scan will normally be of no further diagnostic value. Nuclear medical examinations of the cerebral circulation and metabolism can be carried out in subgroups of patients with headache for the diagnosis and evaluation of complications, when patients experience unusually severe attacks or when the quality or severity of attacks has changed. (vii) Transcranial Doppler examination is not helpful in headache diagnosis. CONCLUSION: Although many of the examinations described in the present guidelines are of little or no value in the clinical setting, most of the tools, including thermal pain thresholds and transcranial magnetic stimulation, have considerable potential for differential diagnostic evaluation as well as for the further exploration of headache pathophysiology and the effects of pharmacological treatment.

A novel zirconium Kα imager for high energy density physics research.

We report on the development and characterization of a zirconium Kα imager for high energy density physics research. The imager consists of a spherically bent quartz crystal operating at 15.7 keV photon energy. We compare the performance of the imager in terms of integrated reflectivity (R(int)) and temperature dependent collection efficiency (η(Te)) to that of the widely used Cu Kα imager. Our collisional-radiative simulations show that the new imager can be reliably used up to 250 eV plasma temperature. Monte Carlo simulations show that for a 25 µm thick tracer layer of zirconium, the contribution to Kα production from photo-pumping is only 2%. We present, for the first time, 2D spatially resolved images of zirconium plasmas generated by a high intensity short pulse laser interacting with Zr solid targets.

Migraines with and without aura and their response to preventive therapy with topiramate.

Data from the Prolonged Migraine Prevention (PROMPT) with Topiramate trial were evaluated post hoc to determine whether topiramate could prevent migraine auras, and whether its efficacy in preventing migraine headaches was similar in patients with (MA; n = 269) and without (MoA; n = 542) aura. Migraines and auras were recorded during prospective baseline, 6-month open-label (OL) topiramate and 6-month double-blind (DB), placebo-controlled phases. In the last 28 OL days, migraines without aura and migraine auras decreased by 43.1% and 54.1%, respectively, in MA patients. MoA patients experienced a 44.3% reduction in migraines. In the DB phase, increases in migraines with placebo vs. topiramate were similar to the full study, but were generally not statistically significant, probably due to lack of power in the subgroup analysis. Similarly, there were no statistically significant changes in number of auras between groups. Thus, topiramate appears to reduce migraine auras in parallel with headache reductions, which are similar in patients with and without aura.

Evaluation and proposal for optimization of neurophysiological tests in migraine: part 2--neuroimaging and the nitroglycerin test.

Neuroimaging methods have been widely used in headache and migraine research. They have provided invaluable information on brain perfusion, metabolism and structure during and outside of migraine attacks, contributing to an improved understanding of the pathophysiology of the disorder. Human models of migraine attacks are indispensable tools in pathophysiological and therapeutic research. This review of neuroimaging methods and the attack-provoking nitroglycerin test is part an initiative by a task force within the EUROHEAD project (EU Strep LSHM-CT-2004-5044837-Workpackage 9) with the objective of critically evaluating neurophysiological tests used in migraine. The first part, presented in a companion paper, is devoted to electrophysiological methods, this second part to neuroimaging methods such as functional magnetic resonance imaging, positron emission tomography and voxel-based morphometry, as well as the nitroglycerin test. For each of these methods, we summarize the results, analyse the methodological limitations and propose recommendations for improved methodology and standardization of research protocols.

[Functional magnetic resonance imaging of the visual cortex: relation between stimulus intensity and bold response]. / Resonancia magnética funcional de la corteza visual: estudio de las relaciones entre la intensidad del estímulo y la respuesta BOLD.

INTRODUCTION: Visual system is a high interest topic in neuroscience research. The new neuroimaging techniques, such as functional magnetic resonance imaging (fMRI), allow us to quickly improve our knowledge on the visual system using non-invasive methods. This work examines the effect of small changes in the intensity of a visual stimulus over the BOLD response in the visual cortex. AIMS: To perform a detailed analysis of the visual cortex reaction to different intensities of a light source and to verify the ties between the intensity of the visual stimulus and the cortical response. SUBJECTS AND METHODS: Using fMRI (3 T), we registered BOLD response (area and intensity of the signal change) in 20 photophobic patients and 20 controls while viewing different stimulus intensities from a light source. RESULTS: We found a direct relation between stimulus intensity and occipital response. We show that cortical reactivity is higher in patients with photophobia than normal controls, specially for the lower and medium intensities. CONCLUSIONS: fMRI is a valid and robust technique to register consistent and reproducible responses in different groups of subjects. It is useful for the study of normal cortex functioning as well as for clinical use.

Magnetic resonance angiography shows dilatation of the middle cerebral artery after infusion of glyceryl trinitrate in healthy volunteers.

Previous studies have reported dilatation of the middle cerebral artery (MCA) during acute glyceryl trinitrate (GTN)-induced headache, using imaging techniques such as transcranial Doppler (TCD), positron emission tomography (PET) and single photon emission computerized tomography (SPECT). In the present study we aimed to evaluate whether magnetic resonance angiography (MRA) may be used to examine the effect of GTN on the MCA, with respect to changes in diameter and cross-sectional area in healthy volunteers. In addition, we wanted to determine the intra- and inter-observer variation of the method. In a randomized, double blind, crossover study 12 healthy volunteers received intravenous infusion of GTN (0.5 microg/kg/min for 20 min) or placebo. Using 1.5 Tesla MRA, we recorded changes in the diameter and cross-sectional area of MCA before, during and after infusion of GTN. The MRA images were evaluated by two blinded, independent observers/neuroradiologists. The primary endpoints were the differences in the AUC for diameter and cross-sectional area of the MCA between the two experimental conditions and the intra- and inter-observer variation. The areas under the curve (AUC) of the MCA diameter and cross-sectional area were significantly greater after GTN than after placebo (P < 0.05). The intra-observer variation (day-to-day) at baseline was 8.3% and 10.9% for the two observers. The mean inter-observer variation of the cross-sectional MCA area was 15.5% and for the diameter measurements 8%. The present study shows that the MRA method gives a reliable semi-quantitative index of the vascular changes in the intra-cerebral arteries after infusion of GTN and may be useful for headache research.

Dose distribution from x-ray microbeam arrays applied to radiation therapy: an EGS4 Monte Carlo study.

We present EGS4 Monte Carlo calculations of the spatial distribution of the dose deposited by a single x-ray pencil beam, a planar microbeam, and an array of parallel planar microbeams as used in radiation therapy research. The profiles of the absorbed dose distribution in a phantom, including the peak-to-valley ratio of the dose distribution from microbeam arrays, were calculated at micrometer resolution. We determined the dependence of the findings on the main parameters of photon and electron transport. The results illustrate the dependence of the electron range and the deposited in-beam dose on the cut-off energy, of the electron transport, as well as the effects on the dose profiles of the beam energy, the array size, and the beam spacing. The effect of beam polarization also was studied for a single pencil beam and for an array of parallel planar microbeams. The results show that although the polarization effect on the dose distribution from a 3 cm x 3 cm microbeam array inside a water phantom is large enough to be measured at the outer side of the array (16% difference of the deposited dose for x-ray beams of 200 keV), it is not detectable at the array's center, thus being irrelevant for the radiation therapy purposes. Finally we show that to properly compare the dose profiles determined with a metal oxide semiconductor field emission transistor detector with the computational method predictions, it is important to simulate adequately the size and the material of the device's Si active element.

Duration of attacks of first division trigeminal neuralgia.

Objective measurements of duration of attacks have been performed in 8 (5 female and 3 male) patients suffering from primary first division (V-1) trigeminal neuralgia. The mean age of the patients was 67.5 +/- 11.4 years, and the mean age at onset 64.0 +/- 9.7 years. During the study the patients were off treatment. A total of 192 attacks were witnessed by the authors and exactly timed by a stop-watch. The duration of attacks ranged from 2 to 32 s, with a mean of 6.5 +/- 6.1 s. The unweighted mean was 8.8 +/- 5.7 s, with a range of 2.4-17.5 s. With the present data the duration of attacks of V-1 neuralgia has been exactly determined, and the clinical distinction of V-1 neuralgia from other shortlasting headaches, particularly from SUNCT, has been substantially clarified.