371 research outputs found
ReMIND2Reg dataset (2023)
No full text<h1>Official training and validation sets of ReMIND2Reg 2024.</h1>
<p>The goal of the ReMIND2Reg dataset is to address the <strong>registration problem</strong> of multi-parametric <strong>pre-operative MRI</strong> and <strong>intra-operative 3D ultrasound</strong> (iUS) images. Specifically, we focus on the challenging problem of <strong>pre-operative to post-resection registration</strong>, requiring the estimation of large deformations and tissue resections. Preoperative MRI comprises two structural MRI sequences: contrast-enhanced T1-weighted (ceT1) and native T2-weighted (T2). However, not all sequences are available for all cases. For this reason, developed methods must have the <strong>flexibility</strong> to leverage incomplete data sets at inference time. </p>
<p>The released data corresponds to a modified (pre-processed) subset of the <strong>Brain Resection Multimodal Imaging Database (ReMIND)</strong> from The Cancer Imaging Archive, released with a <a href="https://creativecommons.org/licenses/by/4.0/">CC BY 4.0 license</a>, which contains pre- and intra-operative data collected on 114 consecutive patients who were surgically treated with image-guided tumor resection between 2018 and 2022: <a href="https://doi.org/10.7937/3rag-d070.">https://doi.org/10.7937/3rag-d070.</a></p>
<p>For each patient, 3D intraoperative ultrasound data reconstructed from tracked 2D sweep were acquired during brain surgery after substantial tumor resection was completed to the degree that either the surgeon was satisfied with the microscopically-visible extent of resection or to identify the remaining portion of the tumor (_0000.nii.gz). Before surgery, contrast-enhanced T1 (ceT1) MR scans (_0001.nii.gz) and/or T2-SPACE (_0002.nii.gz) were acquired to identify the surgical target. </p>
<p>The task is to find one solution for the registration of two pairs of images per patient:<br>1. 3D post-resection iUS and ceT1<br>2. 3D post-resection iUS and T2</p>
<p>The two main challenges are the significant variations in intensity distribution and local information between two imaging modalities (iUS and MR) and the estimation of large deformations with topological changes due to tissue resections. </p>
<p>The released dataset includes training images of 99 patients with 99 3D iUS, 93 ceT1, and 62 T2, and validation images of 5 patients with 5 3D US, 5 ceT1, and 5 T2. The images are paired as described above with two image pairs per patient, resulting in 1585image pairs for training and 10 image pairs for validation. </p>
<p>For details on the image acquisition (scanner details, etc.), please see <a href="https://doi.org/10.1101/2023.09.14.23295596.">https://doi.org/10.1101/2023.09.14.23295596.</a></p>
<p>All images are converted to NIfTI. When more than one pre-operative MR sequence was available, ceT1 was affinely co-registered to the T2 using NiftyReg; Ultrasound images were resampled in the pre-operative MR space. Images were cropped in the field of view of the iUS in an image size of 256x256x256 with a spacing of 0.5x0.5x0.5mm.</p>
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<p><strong>Data citation:</strong><br>Juvekar, P., Dorent, R., Kögl, F., Torio, E., Barr, C., Rigolo, L., Galvin, C., Jowkar, N., Kazi, A., Haouchine, N., Cheema, H., Navab, N., Pieper, S., Wells, W. M., Bi, W. L., Golby, A., Frisken, S., & Kapur, T. (2023). The Brain Resection Multimodal Imaging Database (ReMIND) (Version 1) [dataset]. The Cancer Imaging Archive. <a href="https://doi.org/10.7937/3rag-d070.">https://doi.org/10.7937/3rag-d070.</a></p>
100 MeV proton beam monitoring devices.
No full textMethods for monitoring the intensity of the external proton beam from the 100 Mev McGill Synchrocyclotron were investigated. By using the Faraday Cup and the ionization chamber, it is possible to measure the beam current over a range 10^-14 amp. to 10^-8 amp. An integrator circuit providing the suitable ranges was built and calibrated to 0.4% accuracy. For low beam intensity, high background and short burst experiments, the C11 activation method is recommended. The cross section for C11 activation has been measured to be (63.8 +0.8/-0.6) mb for 96 Mev protons. This will then provide an additional accurate monitor for beam intensity
Magnetic extraction of the proton beam from the McGill Synchrocyclotron.
No full textThis thesis describes the successful extraction of the full energy proton beam from the McGill synchrocyclotron. Extraction was achieved by increasing the radial separation for the last few orbits by the process of non-linear regenerative magnetic deflection, and then leading the last orbit into a magnetic channel. Design and installation of the magnetic regenerator and the magnetic channel are described in the main body of this thesis, and theoretical development of the design criteria is given in the appendix. The extracted beam has been focused to a spot 1.3 x 4.8 mm with a divergence of 1° at a position 15 feet from the channel exit. It has a pulsed time structure consisting of 15 x 10-^6 sec. bursts repeated 400 times per second, and an average intensity of 4 x 10^-9 amperes
Body position affects performance in untrained cyclists
No full textObjective: To compare cardiovascular and ventilatory variables in upright versus aero cycle ergometry at submaximal and maximal exercise intensities in untrained cyclists.
Method: Ten physically active men (mean (SD) age 19.1 (1.10) years) who were unfamiliar with aerobars underwent maximal exercise testing and steady state cycling at 50, 100, and 150 W.
Results: Participants had significantly greater maxima for oxygen uptake (Vo2), ventilation, heart rate, and workload maximum in the upright position. During steady state cycling at the three workloads, Vo2 (ml/kg/min) and gross mechanical efficiency were significantly greater in the upright position.
Conclusions: In untrained subjects performing with maximal effort, the upright position permits greater Vo2, ventilation, heart rate, and workload maxima. Further, in the steady state, exercise cycling may be less costly in the upright position. For this reason, untrained cyclists need to weigh body position effects against the well known aerodynamic advantages of the aero position.M C Ashe, G C Scroop, P I Frisken, C A Amery, M A Wilkins, K M Kha
Observation of delayed proton radioactivity
No full textThe observation of delayed proton emission is reported. Bombardment of both aluminum and silicon with 97-Mev protons leads to the emission of delayed proton energy groups from to 5 Mev. They follow the beta decay of S25 (T1/2 about 0.3 sec) to proton-unstable excited states of Al25. Delayed protons were also observed following bombardment of Mg, Na, F, X, and O
WET OXIDATION OF AN EPITAXIAL NIOBIUM FILM
No full textAbstract Freshly ion-milled surfaces of epitaxial niobium film were exposed to humid environments and then depth profiled for contaminants by Secondary Ion Mass Spectroscopy (SIMS). Two exposures were used: 30% humid laboratory air, and heavy water vapour in argon
Computer Assisted Relief Generation - a Survey
No full textIn this paper we present an overview of the achievements accomplished to date in the field of computer aided relief
generation. We delineate the problem, classify the different solutions, analyze similarities, investigate the evelopment and review the approaches according to their particular relative strengths and weaknesses. In consequence this survey is likewise addressed to researchers and artists through providing valuable insights into the theory behind the different concepts in this field and augmenting the options available among the methods presented with regard to practical application
Kinematics of electron–proton collisions
No full text Kinematics of electron–proton collisions are presented for massless and massive parton constituents and outgoing leptons. </jats:p
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