Mobile intraoperative CT-assisted frameless stereotactic biopsies achieved single-millimeter trajectory accuracy for deep-seated brain lesions in a sample of 7 patients

BACKGROUND Brain biopsies are crucial diagnostic interventions, providing valuable information for treatment and prognosis, but largely depend on a high accuracy and precision. We hypothesized that through the combination of neuronavigation-based frameless stereotaxy and MRI-guided trajectory planning with intraoperative CT examination using a mobile unit, one can achieve a seamlessly integrated approach yielding optimal target accuracy. METHODS We analyzed a total of 7 stereotactic biopsy trajectories for a variety of deep-seated locations and different patient positions. After rigid head fixation, an intraoperative pre-procedural scan using a mobile CT unit was performed for automatic image fusion with the planning MRI images and a peri-procedural scan with the biopsy cannula in situ for verification of the definite target position. We then evaluated the radial trajectory error. RESULTS Intraoperative scanning, surgery, computerized merging of MRI and CT images as well as trajectory planning were feasible without difficulties and safe in all cases. We achieved a radial trajectory deviation of 0.97 ± 0.39 mm at a trajectory length of 60 ± 12.3 mm (mean ± standard deviation). Repositioning of the biopsy cannula due to inaccurate targeting was not required. CONCLUSION Intraoperative verification using a mobile CT unit in combination with frameless neuronavigation-guided stereotaxy and pre-operative MRI-based trajectory planning was feasible, safe and highly accurate. The setting enabled single-millimeter accuracy for deep-seated brain lesions and direct detection of intraoperative complications, did not depend on a dedicated operating room and was seamlessly integrated into common stereotactic procedures

Positron-neutrino correlations in 32Ar and 33Ar Decays: Probes of Scalar weak currents and nuclear isospin mixing

The positron-neutrino correlation in the 0^+ \to 0^+ \beta decay of ^{32}Ar was measured at ISOLDE by analyzing the effect of lepton recoil on the shape of the narrow proton group following the superallowed decay. Our result is consistent with the Standard Model prediction; for vanishing Fierz interference we find a=0.9989 \pm 0.0052 \pm 0.0036. Our result leads to improved constraints on scalar weak interactions. The positron-neutrino correlation in ^{33}Ar decay was measured in the same experiment; for vanishing Fierz interference we find a=0.944 \pm 0.002 \pm 0.003. The ^{32}Ar and ^{33}Ar correlations, in combination with precision measurements of the half-lives, superallowed branching ratios and beta endpoint energies, will determine the isospin impurities of the superallowed transitions. These will provide useful tests of isospin-violation corrections used in deducing |V_{\rm ud}| which currently indicates non-unitarity of the KM matrix.Comment: 15 pages, 6 figure

Precise measurements of the energy losses of heavy ions

Accurate measurements of the energy loss of all charged particles are needed to determine the reliability of the Bethe theory of stopping power. Few measurements have been made for particles with energies greater than 20 MeV/u. A first step to accurate measurements is to establish the precision of an experimental method. The authors report here about the recent energy loss measurements for 290 MeV/u carbon ions from the HIMAC. They have been made with the method used for 70 MeV protons. The ion beam traverses an absorber of thickness t and the residual range of the ions is measured with a water container of adjustable thickness (``range gauge``)

Derivations of Atomic Ionization Effects Induced by Neutrino Magnetic Moments

A recent paper [M.B. Voloshin, Phys. Rev. Lett. 105, 201801 (2010)] pointed out that our earlier derivations of atomic ionization cross-section due to neutrino magnetic moments (arXiv:1001.2074v2) involved unjustified assumptions. We confirm and elaborate on this comment with these notes. We caution that the results of the sum-rule approach in this paper contradict the expected behaviour in atomic transitions.Comment: V3 3 pages ; confirm and elaborate on unjustified assumptions in V1 & V

Deep brain electrical neurofeedback allows Parkinson patients to control pathological oscillations and quicken movements

Parkinsonian motor symptoms are linked to pathologically increased beta-oscillations in the basal ganglia. While pharmacological treatment and deep brain stimulation (DBS) reduce these pathological oscillations concomitantly with improving motor performance, we set out to explore neurofeedback as an endogenous modulatory method. We implemented real-time processing of pathological subthalamic beta oscillations through implanted DBS electrodes to provide deep brain electrical neurofeedback. Patients volitionally controlled ongoing beta-oscillatory activity by visual neurofeedback within minutes of training. During a single one-hour training session, the reduction of beta-oscillatory activity became gradually stronger and we observed improved motor performance. Lastly, endogenous control over deep brain activity was possible even after removing visual neurofeedback, suggesting that neurofeedback-acquired strategies were retained in the short-term. Moreover, we observed motor improvement when the learnt mental strategies were applied 2 days later without neurofeedback. Further training of deep brain neurofeedback might provide therapeutic benefits for Parkinson patients by improving symptom control using strategies optimized through neurofeedback

Muon Simulations for Super-Kamiokande, KamLAND and CHOOZ

Muon backgrounds at Super-Kamiokande, KamLAND and CHOOZ are calculated using MUSIC. A modified version of the Gaisser sea level muon distribution and a well-tested Monte Carlo integration method are introduced. Average muon energy, flux and rate are tabulated. Plots of average energy and angular distributions are given. Implications on muon tracker design for future experiments are discussed.Comment: Revtex4 33 pages, 16 figures and 4 table

Positron-neutrino correlation in the 0^+ \to 0^+ decay of ^{32}Ar

The positron-neutrino correlation in the $0^+ \to 0^+ \beta$ decay of $^{32}$Ar was measured at ISOLDE by analyzing the effect of lepton recoil on the shape of the narrow proton group following the superallowed decay. Our result is consistent with the Standard Model prediction. For vanishing Fierz interference we find $a=0.9989 \pm 0.0052 \pm 0.0036$, which yields improved constraints on scalar weak interactions

Light flash phenomenon seen by astronauts

The results from experiments conducted to characterize and elucidate light flashes seen by astronauts on Apollo 11, 12, 13, and 14 during transluna or transearth orbit are presented. The data show cosmic nuclei interacting with the visual apparatus causes the light flash phenomenon. The data also suggest that slow protons and helium ions with a stopping power greater than 10 KeV/micron will cause light flashes and streaks in the partially dark adapted eye. The effects of galactic cosmic nuclei interacting with man during long term missions are discussed

The KATRIN Pre-Spectrometer at reduced Filter Energy

The KArlsruhe TRItium Neutrino experiment, KATRIN, will determine the mass of the electron neutrino with a sensitivity of 0.2 eV (90% C.L.) via a measurement of the beta-spectrum of gaseous tritium near its endpoint of E_0 =18.57 keV. An ultra-low background of about b = 10 mHz is among the requirements to reach this sensitivity. In the KATRIN main beam-line two spectrometers of MAC-E filter type are used in a tandem configuration. This setup, however, produces a Penning trap which could lead to increased background. We have performed test measurements showing that the filter energy of the pre-spectrometer can be reduced by several keV in order to diminish this trap. These measurements were analyzed with the help of a complex computer simulation, modeling multiple electron reflections both from the detector and the photoelectric electron source used in our test setup.Comment: 22 pages, 12 figure