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Borate Phosphors for Radiation Dosimetery
Published in S. K. Omanwar, R. P. Sonekar, N. S. Bajaj, Borate Phosphors, 2022
One of the important applications of OSL dosimetry has been found in the field of medical physics due to their use in radio-diagnosis, nuclear medicine and radiotherapy. OSLDs have become popular in these fields due to their high sensitivity, miniature size, tissue equivalence, high stability to environmental conditions, low OSL fading, reusability, linear dose response, sufficient precision and accuracy. OSL phosphors, such as Li2B4O7:Cu-Ag, fluoride-based phosphors have been widely used for clinical dosimetric measurements e.g. central axis depth-dose curves, inphantom measurements, in-vivo dosimetry, surface doses, quality assuarance, etc. of high-energy photon and electron beams. Applications of OSL phosphors in medical dosimetry are described by Akselrod and McKeever [170], Pradhan [171] and Yukihara [172]. OSL dosimeters are popular in many hospitals for external dosimetry during these treatments. OSL has the potential for the development of near-real-time dosimetry in which the measured quantity can be either dose (Sv) or dose rate (Sv/s). Typical doses of interest can be up to 20 Sv [173,174].
Radiation Protection Issues in X-ray Radiology, Fluoroscopy, and Computed Tomography
Published in Paolo Russo, Handbook of X-ray Imaging, 2017
When the right protocol has been chosen, the operator has to know which parameters play a major role on the image quality and also the patient dose, such as frame rate, fluoroscopy or fluorography, beam incidence, and patient position in the primary beam. There are no straightforward rules as to how the dose rate adapts to the different input parameters (patient body habitus, beam angle, field size, magnification setting, detector sensitivity, etc.) (Vaño et al. 2009). In order to get a better understanding of the influence of those parameters, a good—although time-consuming—way to sort out their respective influences is to measure the device's dose rate using controlled conditions, such as a dosimetry system (semi-conducting or ionization chamber) and a phantom (anthropomorphic or PMMA slabs) that simulates the patient. The dose rate that will be measured at the entrance point of the beam in the slabs, containing a given fraction (30% to 40%) of backscattered radiation, is known as the Skin Entrance Exposure Rate (SEER). The measurements can be performed by a device user, a radiation protection expert, or a medical physics expert. An example of the results can be seen in Figure 66.7.
The Medical Implications of Nuclear Power Plant Accidents
Published in W.A. Crosbie, J.H. Gittus, Medical Response to Effects of Ionising Radiation, 2003
implications of the environmental hazard. The medical physicist of the Health Authority would need to communicate direct from OSC with other medical physics colleagues, notably the Regional Radiation Protection Adviser. Such an input to the decision making process not only allows the health services, including the Environmental Health Authority, to fulfil its statutory functions towards the health of the community, but also broadens the basis of professional consultation and advice on the nature and extent of the hazard. It is important that this input should be at the earliest possible moment, since some of the most important decisions, notably concerning evacuation and/or the issuing of potassium iodate tablets, may have to be taken at a very early stage of the emergency. Indeed, such decisions may have to be taken before the OSC gets established, and this would obviously be dependent on the best advice available even at the site control. Nevertheless, at every stage thereafter, the medical physics and health adviser input from the health desk should be secured.
The New Zealand Parkinson’s progression programme
Published in Journal of the Royal Society of New Zealand, 2023
Michael R. MacAskill, Toni L. Pitcher, Tracy R. Melzer, Daniel J. Myall, Kyla-Louise Horne, Reza Shoorangiz, Mustafa M. Almuqbel, Leslie Livingston, Sophie Grenfell, Maddie J. Pascoe, Ethan T. Marshall, Steven Marsh, Sarah E. Perry, Wassilios G. Meissner, Catherine Theys, Campbell J. Le Heron, Ross J. Keenan, John C. Dalrymple-Alford, Tim J. Anderson
A major advance came with the establishment of the Van der Veer Institute for Parkinson’s and Brain Research in 2004. This was created as an independent research organisation to host research and clinical staff and postgraduate students from the Universities of Canterbury and Otago and the Canterbury District Health Board. The goal was to bring people together from multiple institutions and disciplines in a facility that combined both research and clinical services. Research into Parkinson’s has continued to be the major focus of the organisation, notwithstanding its subsequent renaming as the New Zealand Brain Research Institute (NZBRI) in 2011. The Van der Veer bequest enabled the establishment of a Chair in Movement Disorders, held by Tim Anderson (Department of Medicine, University of Otago, Christchurch). The creation of the Institute enabled a strengthened multidisciplinary collaboration centred around his specialisation in clinical neurology and John Dalrymple-Alford’s expertise in neuropsychology. In 2006, the country’s first 3 tesla, research-grade, MRI scanner was installed below the Institute, in a partnership with Pacific Radiology Group (and particularly neuroradiologist Dr Ross Keenan) and Dr Richard Watts (Department of Medical Physics, University of Canterbury), a physicist specialising in magnetic resonance imaging (Watts 2005).
A Study on Interactions of 14.7-MeV Protons and 3.6-MeV Alphas in 93Nb Target
Published in Fusion Science and Technology, 2023
For target damage in the SRIM code, there are two basic options: the Kinchin-Pease (K-P) and Full-Cascades methods. We used a computation method providing quick statistical predictions based on the K-P formalism. GEANT4 is a software toolkit written in the C++ language that allows us to carry out a detailed calculation of the propagation of particles interacting with materials.[22,25] It is based on two independent studies that began investigating possible improvements to the existing GEANT3 simulation software at CERN and KEK in 1993. The GEANT4 Monte Carlo simulation toolkit has been used to obtain new data in a large number of different scientific fields, such as astrophysics and space science, medical physics, high-energy physics, accelerator-based physics, nuclear physics, and radiation protection. It includes a complete set of functionality, including tracking, geometry, physics models for creating an application on the simulations of interaction of particles through matter, and using Monte Carlo methods in a wide range of energies. It provides for modeling hadronic processes using models such as the Bertini model, the Fritiof with Precompound, and the Quark-Gluon String with Precompound. The present simulations were carried out with version 11.0.0 of the GEANT4 code.[22,25]
Comprehensive radiological parameterizations of proton and alpha particle interactions for some selected biomolecules: theoretical computation
Published in Radiation Effects and Defects in Solids, 2023
Abayomi M. Olaosun, Denen E. Shian
Investigation of the interaction of radiations with biomolecules has several applications in the fields of radiation biophysics, radiation protection, medical biology, and medical physics. In this study, a comprehensive radiological parameterization of proton and alpha particles interactions at the energy range of (0.001–10,000 MeV) and (0.001–10,000 MeV), respectively for nucleotide bases (adenine, guanine, cytosine, uracil, thymine), carbohydrates (glucose, sucrose, raffinose), lipids (cholesterol, retinol, progesterone, cortisone, and phylloquinone), and fatty acids (lauric, myristic, palmitic, stearic, oleic, linoleic, linolenic, arachidonic, and arachidic) biomolecules have been theoretically computed using PAGEX computer software. The highest values of S(E)/ρ and Sc of proton and alpha particle interactions with the biomolecules occurred at the kinetic energy of about 0.1 and 0.5 MeV, respectively while that of the Zeff and Neff occurred at 0.1 and 1 MeV, respectively. The comparisons of the Zeff and Neff calculated in this study, using PAGEX software with some studies in the literature that used the interpolation method showed variations that account for differences between the two methods.