Search results for "medical physics"
showing 10 items of 579 documents
NMR relaxometry measurements of Fricke gel dosimeters exposed to neutrons
2014
Fricke infused gel matrices offer several features making them suitable for dosimetric applications; among the set here are tissue equivalence, low cost and ease of preparation. Their nuclear magnetic resonance (NMR) relaxation properties can be used as a radiation detector for the dosimetry of beams used in cancer therapy. In recent years neutron capture therapy has been resumed for the treatment of various types of cancer and it requires three-dimensional mapping of the neutron fields. In this work, we investigated this particular application through NMR relaxometry and MR imaging of Fricke gels exposed to neutrons. We analyzed both the R1 and R2 relaxation rates, which relate to the long…
Ion-Trap Spectrometry for Exotic Nuclei
2010
Abstract Recent progress in manipulation of radioisotopes and their applications in precision measurements on exotic nuclei are reviewed.
Improvement of ESR dosimetry for thermal neutron beams through the addition of gadolinium.
2007
In this paper, the addition of gadolinium is proposed as a useful tool to enhance the electron spin resonance (ESR) sensitivity of organic compounds to thermal neutrons. The target of this work is the detection, through the ESR technique, of the thermal neutron fluence in a mixed field of photons and neutrons. Gadolinium was chosen because it has a very high capture cross section to thermal neutrons; its nuclear reaction with thermal neutrons induces complex inner shell transitions that generate, besides other particles, Auger electrons, which in turn release their energy in the neighborhood (only several nanometers) of the place of reaction. Gadolinium was added to two organic molecules: a…
OPS — Operation Planning System for Neurosurgery
1993
The departments for neuroradiology and neurosurgery intend to use computer aided methods for individual planning of operations in the sella region. Essential structures like the optic nerve, arteries, aneurysms, the pituitary stalk, ventricles, and tumors should be segmented, reconstructed and visualized. The computed 3D view shall simulate the neurosurgeon’s view through the operation microscope into the scene. This approach shall remedy the lack of available medical image analysis systems for neurosurgical intervention. The emphasis in this article will be on the segmentation algorithms and the impact of the system on daily neuroradiological work.
Acousto-optic interaction in polyimide coated optical fibers with flexural waves
2017
Acousto-optic coupling in polyimide-coated single-mode optical fibers using flexural elastic waves is demonstrated. The effect of the polyimide coating on the acousto-optic interaction process is analyzed in detailed. Theoretical and experimental results are in good agreement. Although the elastic attenuation is significant, we show that acousto-optic coupling can be produced with a reasonably good efficiency. To our knowledge, it is the first experimental demonstration of acousto-optic coupling in optical fibers with robust protective coating.
<title>Study of color centers in optical fibers to be used for ITER plasma diagnostics</title>
2007
ABSTRACT The paper presents a comparative study, by off-line measurements of the irradiation induced optical attenuation in several large diameter (600 µm) optical fibers subjected to gamma-rays and neutron irradiation. The optical fiber samples fall into two categories: optical fibers with an enhanced UV transmission (high OH content core) and solarization resistant optical fibers. The irradiation conditions were as follows: a) gamma irradiation at a 60 Co source, with a dose rate of 0.33 kGy/h +/- 5%, up to the maximum total irradiation dose of 313 kGy; b) neutron irradiation (mean energy 5.2 MeV) using a deuteron beam (13 MeV) and a thick beryllium target, for a total fluence of 6x10 12 …
Precision-cut liver slices: A tool to model the liver ex vivo
2013
D is ea se Precision-cut liver slices: A tool to model the liver ex vivo Peter Olinga1,2,*, Detlef Schuppan2 1Division of Pharmaceutical Technology and Biopharmacy, Departement of Pharmacy, University of Groningen, The Netherlands; 2Molecular and Translational Medicine, Department of Medicine I, University Medical Center, Johannes Gutenberg University Mainz, Germany *Corresponding author. Address: Division of Pharmaceutical Technology and Biopharmacy, Departement of Pharmacy, University of Groningen, The Netherlands. Tel.: + 31 50 363 8373; fax: +31 50 363 2500. *E-mail address: P.Olinga@rug.nl
Editorial: guidelines for oral and maxillofacial radiology
2017
PenRed: An extensible and parallel Monte-Carlo framework for radiation transport based on PENELOPE
2021
Monte Carlo methods provide detailed and accurate results for radiation transport simulations. Unfortunately, the high computational cost of these methods limits its usage in real-time applications. Moreover, existing computer codes do not provide a methodology for adapting these kind of simulations to specific problems without advanced knowledge of the corresponding code system, and this restricts their applicability. To help solve these current limitations, we present PenRed, a general-purpose, stand-alone, extensible and modular framework code based on PENELOPE for parallel Monte Carlo simulations of electron-photon transport through matter. It has been implemented in C++ programming lan…
Standardized staining methods: Feulgen-Rossenbeck reaction for desoxyribonucleic acid and periodic acid-Schiff (PAS) procedure
2002
A project group working under the European Confederation of Laboratory Medicine (ECLM) presents recommendations for standardized procedures for the Feulgen-Rossenbeck-Schiff and the periodic acid-Schiff (PAS) reactions on cytological and histological material. The advantages and disadvantages of such standardized procedures are presented here in a preamble. Both users and manufacturers are encouraged to give their opinions with a view to achieving consensus on these procedures and on how further work on these lines may proceed.