Short-Lived Positron Emitting Radionuclides
Frank Helus, Lelio G. Colombetti in Radionuclides Production, 2019
As disadvantage may be mentioned that the radioactivity must be prepared immediately before application, which makes the access to an in-house charged particle accelerator like a medical or compact cyclotron, necessary. It is obvious that application of these nuclides is not possible if information must be collected over a long period of time compared to the half-life of the nuclide. For the preparation of useful amounts of labeled product large amounts of radioactivity have to be handled with as consequence that for the protection of the personnel, automation and remote control of the procedures are necessary. Also heavy lead shielding of 5 to 10 cm has to be installed.
Low Energy Particle Accelerators and Laboratories
Vlado Valković in Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
High Voltage Engineering Europa B.V. (HVE, Amsterdamseweg 63, 3812 RR Amersfoort, the Netherlands) is one of the largest and most diverse manufacturers of particle accelerator systems for science and industry. In the period 1959–2005 it was a subsidiary of HVEC, USA; since 2005 until now is subsidiary of Aimland Technologies, NL. The company is specialized in the development and manufacture of ion beam and electron beam technology-based equipment. In addition to research-type accelerator systems HVE also manufactures industrial-type accelerator systems and sub-assemblies for semiconductor ion implantation systems and of electron beam processing systems.
Proton Accelerators
Harald Paganetti in Proton Therapy Physics, 2018
Currently, a lot of research is done in the field of particle acceleration by means of laser pulses [68]. At the moment, most experience has been obtained with the target normal sheet acceleration (TNSA) method [69]. As shown in Figure 3.28, a high-intensity laser irradiates the front side of a solid target. At the front surface, a plasma is created due to the energy absorption in the foil. The electrons in this plasma are heated and emerge from the rear surface. This induces strong electric fields, which pull ions and protons out of the evaporating target.
Surface Modification of lactose carrier particles using a fluid bed coater to improve fine particle fraction for dry powder inhalers
Published in Pharmaceutical Development and Technology, 2023
Qin Qin Gong, Justin Yong Soon Tay, Natalia Veronica, Jian Xu, Paul Wan Sia Heng, Yong Ping Zhang, Celine Valeria Liew
During inhalation, the carrier particles leaving the device will mostly be deposited at the back of the throat while the drug particles detach themselves from the carrier particles. After detachment, the drug particles will be conveyed to the lower airways with the inspiratory airflow (Islam et al. 2004). The extent of drug detachment will ultimately determine the performance of the DPI. Drug detachment from carrier particles is primarily governed by two mechanisms, flow stream (fluid forces) and impact (mechanical forces) (Voss and Finlay 2002; de Boer et al. 2003). Separation of drug particles from carrier particles by flow stream mainly involves aerodynamic lift and drag due to air turbulence. In contrast, drug separation from carrier particles by impact is related to a sudden change in particle acceleration or velocity due to collisions, generating a separation force. With an increase in the surface roughness of the carrier particles, drug particles may be shielded by the undulating edges on the carrier particles, and the drug detachment depends more on the mechanical forces of separation where other factors influencing drug-carrier adhesive forces (Donovan and Smyth 2010) such as van der Waals forces, electrostatic forces and capillary forces may also play their roles. The magnitude of these forces is affected by the physicochemical properties of both the carrier and the drug particles, such as the surface properties, contact surface area and environmental conditions (Buckton 1997; Young and Price 2004).
Focus small to find big – the microbeam story
Published in International Journal of Radiation Biology, 2018
The first application of the microbeam by Zirkle back in 1950s was to look at the role of radiation during mitosis (Zirkle and Bloom 1953). With modern microbeam settings and an advanced imaging system, spatiotemporal analysis of DNA damage repair can be studied with a live imaging system. Using a charged particle accelerator, Tobias et al. (2010) visualized the kinetics of repair-related proteins being recruited to DNA damage sites after irradiation. Fast recruited proteins like DNA-PK or XRCC1 or slower recruited proteins like 53BP1 or MDC1 were classified by microbeam microscopy, and this classification helped to establish the hierarchical organization of damage recognition and subsequent repair events. Due to the subnuclear dose deposition by the microbeam and the development of fluorescent protein tags, the accumulation of different repair proteins to DNA damage sites and their mobility can be efficiently analyzed. With the combination of microbeam and fluorescence tagged proteins, roles of proteins involved in various biological processes can be analyzed in a real-time manner.
Dosimetry study on Auger electron-emitting nuclear medicine radioisotopes in micrometer and nanometer scales using Geant4-DNA simulation
Published in International Journal of Radiation Biology, 2020
Seifi Moradi Mahdi, Shirani Bidabadi Babak
The results show that on a single-cell scale, each radioisotope transmits more dose than 131I (the exception is only in three configurations N ← Cy, N → CS and C → CS for 99Tc) and, on the other hand, they transmit small amounts of dose to healthy cells adjacent to the cancerous cell (up to 2.5%). These diagnostic radioisotopes have a good half-life and easier access to them. For example, access to therapeutic 211At radioisotope is limited due to the need for an alpha particle accelerator with moderate energy to produce it. Another 211At problem, its daughter, is 110Po, which emits alpha particles with a half-life of 138.4 days. Also, due to the proper energy of the Auger electrons and the internal conversion electrons of these diagnostic radioisotopes, they can also be used in cluster irradiation of cancer cells.
Related Knowledge Centers
- Cyclotron
- Deuterium
- Radionuclide
- Relativistic Heavy Ion Collider
- Synchrotron Light Source
- Particle Therapy
- Oncology
- Cockcroft–Walton Generator
- Linear Particle Accelerator
- Hydrogen