Application of Synchrotron Radiation Technology in Marine Biochemistry and Food Science Studies
Se-Kwon Kim in Marine Biochemistry, 2023
Synchrotrons are particle accelerators in which charged particles circulate along a closed path. A charged particle, an electron, in the magnetic field, is accelerated to the speed of light. Because SR is extremely bright compared to conventional X-ray generators and microscopes, it is gentle to soft materials, has a variable wavelength (energy), and a high directivity, similar to a laser. SR-based X-ray contrast resolution is known to be >1000 times higher than the density resolution of X-ray absorption. SR can measure in nanosecond order with a pulse duration of 50–100 picoseconds (Nakano 2019; Pérez and De Sanctis 2017; Rao et al. 2013). Therefore, in particular, SR-based imaging is recently attracting many scientists studying on medical and biological applications. At present, a next-generation SR light source facility, which will provide the first synchrotron beam in 2023, is under construction at the Aobayama campus of Tohoku University in Sendai, Japan (Figure 2.5; PhoSIC 2019).
X-ray Vision: Diagnostic X-rays and CT Scans
Suzanne Amador Kane, Boris A. Gelman in Introduction to Physics in Modern Medicine, 2020
The type of x-ray tube described above is currently the standard source for clinical x-ray imaging. However, there are other sources for the production of x-ray radiation. As we discussed above, bremsstrahlung radiation is emitted by electrons as they slow down and change the direction of their motion due to the attraction of atomic nuclei. Similarly, electrons can be made to move on circular orbits using magnetic fields applied perpendicular to the motion of the electrons. Accelerators using such bending magnets are called synchrotrons. Electrons in synchrotrons reach energies of the order of several millions of kiloelectron-volts. Accelerated electrons emit radiation called synchrotron radiation with characteristic frequencies in the x-ray range of the spectrum. Synchrotrons emit very intense and highly collimated beams of x-ray radiation. In recent years, there has been progress in developing compact synchrotron sources suitable for clinical applications.
Proton Accelerators
Harald Paganetti in Proton Therapy Physics, 2018
Proton therapy has been developed and was performed initially in nuclear physics laboratories that were equipped with a particle accelerator, such as a (synchro)cyclotron or a synchrotron, like in Berkeley (CA, USA) [1,2], Cambridge (MA, USA) [3], Paul Scherrer Institute (PSI; Switzerland) [4–6], and Uppsala (Sweden) [7,26]. The first hospital-based facility with gantries was built in Loma Linda (CA, USA) [8] in the 1990s. Around that time, also commercial companies started to develop accelerators and offered complete treatment facilities, including gantries. Nowadays, the cyclotron and the synchrotron are the two typical types of accelerators that are offered by companies and are proven to be reliable machines in clinical facilities. Many good textbooks and proceedings of accelerator schools exist on accelerator design, see for example [9,10], but in this chapter, the emphasis will be on relevant issues of proton therapy to understand the reason for the typical design choices and to become aware of the important technical and accelerator physics issues that should be discussed in a selection and acquisition procedure.
In vivo percutaneous permeation of gold nanomaterials in consumer cosmetics: implication in dermal safety assessment of consumer nanoproducts
Published in Nanotoxicology, 2021
Mingjing Cao, Bai Li, Mengyu Guo, Ying Liu, Lili Zhang, Yaling Wang, Bin Hu, Jiayang Li, Duncan S. Sutherland, Liming Wang, Chunying Chen
SRXRF was used to unveil the skin permeation route by imaging the Au in the skin. Excised skins embedded in optimal cutting temperature (O.C.T.) compound were sliced into 40 μm-thick sections from the skin surface to subcutaneous layer vertically and dried on Mylar films. Elemental mapping was performed at beamline 15U1 of the shanghai synchrotron radiation facility (SSRF), China. The light spot size of the synchrotron radiation was set to 150 × 40 μm2. Monochromatic synchrotron radiation with an energy of 12.5 keV was used to excite the samples. The shift step of the sample platform along the X and Z directions was set as the same size as the spot. The XRF signal was collected using a Si (Li) detector at a speed of 3 s/step. Fluorescence intensities of Au, P, Zn, S, K, Ca, and Compton scattering were simultaneously recorded by 8 single-channel analyzers (Ortec 550). XRF images were normalized to pre-ionization chamber counts and Compton scatter intensity with Igor Pro software and graphed by Origin software.
Proton vs. photon radiotherapy for MR-guided dose escalation of intraprostatic lesions
Published in Acta Oncologica, 2021
Maryam Moteabbed, Mukesh Harisinghani, Harald Paganetti, Alexei Trofimov, Hsiao-Ming Lu, Jason A. Efstathiou
Proton plans were generated using the Astroid v2 treatment planning system [27–29]. A fixed relative biological effectiveness (RBE) of 1.1 was used. Bilateral opposed beams with single field optimization (SFO) were applied to ensure adequate plan robustness with respect to the proton rangeuncertainty. The spot size was ∼3 mm median sigma at the relevant beam range (18–30 cm) at the isocenter in the air as achievable on our synchrotron-based gantry. The spot spacing was set to 0.8 sigma and layer spacing to 0.8 times the width of the most distal Bragg peak at 80% dose. Robustness to range uncertainties was confirmed by performing dose recalculations after ±3.5% rescaling of the HU to relative stopping power. The photon plans were created using RayStation planning system (RaySearch Laboratories, Sweden) in volumetric modulated arc therapy (VMAT) mode with 2 full arcs with opposite rotations, 6 MV photon energy, 20 degrees collimator angle, and 0.5 cm leaf width at the isocenter.
Elke Bräuer-Krisch: dedication, creativity and generosity: May 17, 1961–September 10, 2018
Published in International Journal of Radiation Biology, 2022
Elke acquired her basic formation as radiation protection engineer in Germany, at the Berufsakademie Karlsruhe (1980–1984). The following decade was devoted to an extensive international professional development, with residencies in: (A) Institut Laue Langevin, Grenoble, France (1984–1986). (B) National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (Upton, NY) (1986–1987 and 1993–1994). (C) DESY (Deutsches Elektronen-Synchrotron, Hasylab) in Hamburg, Germany (1987–1988). (D) Australian Nuclear Science and Technology Organisation (ANSTO) in Sydney, Australia. (E) European Synchrotron Radiation Facility (ERSF) in Grenoble, France (1983–1990), where she moved to a position of safety engineer in 1990. In 1998, Elke joined the Biomedical Beamline at the ESRF. What happened in the years between?
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