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Radionuclide Production
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
A cyclotron is composed by four systems. A resistive magnet that can create a magnetic field of 1–2 Tesla (T)A vacuum system down to 10-5 Pa.A high frequency system (about 40 MHz) providing a voltage with a peak value of about 40 kV, although these figures can vary considerably for different systems.An ion source that can ionize hydrogen to create free protons as well as deuterium and eventually alpha-particles.
Positron Emission Tomography Imaging Systems And Applications
Published in Bhagwat D. Ahluwalia, Tomographic Methods in Nuclear Medicine: Physical Principles, Instruments, and Clinical Applications, 2020
15O, 13N, 11C, and 18F radionuclides are short half-lived radionuclides produced in a cyclotron by bombardment of accelerated particles on stable compounds. Numerous hospitals have a cyclotron on the premises for clinical use. In 1955, the first cyclotron was installed at Hammersmith Hospital in London for the research and medical use of short-lived radionuclides. Within 10 years after the installation of the first medical cyclotron, Washington University, Mallinckrodt Institute of Radiology, MGH and Sloan-Kettering Cancer Institute acquired a cyclotron for production of positron emitters. In the early 1970s there were less than a dozen cyclotrons in medical institutions, whereas now there are over 50 dedicated cyclotrons all over the world. There are over 24 medical cyclotrons in North America, 20 in Europe, the rest are in Japan, South America, and Saudi Arabia. Different energy cyclotrons are available, the cyclotron energy limits being the production mechanism. In general, protons, deutrons, 3He, or 4He particles are accelerated in the cyclotron. A cyclotron can be a fixed energy or a variable energy machine. Figure 1 shows a Cyclotron Corporation Model CS30 fixed energy cyclotron, installed in a hospital. A variety of small and large cyclotrons are now available for production of positron emitters. Some small cyclotrons are quite compact and have built in shielding. Large cyclotrons require special shielding considerations.
Development of Radiobiology: A Review
Published in Kedar N. Prasad, Handbook of RADIOBIOLOGY, 2020
Soon after the discovery of the X-ray and naturally occurring radioactive substances, Thompson defined the physical properties of electrons and protons.17 In 1911, Rutherford, at the University of Cambridge, discovered alpha-particles, and in 1932 Chadwick made the discovery of neutrons.17 The availability of neutrons made possible the production of several radioisotopes of biological and medical interest. Also, the relative biologic effectiveness of neutrons with respect to the X-ray was investigated. In 1932, the invention of particle accelerators (the cyclotron) by Lawrence at the University of California, Berkeley, was of great significance.17 Since then, the cyclotron has been used as a means of production of several radioisotopes of biological and medical interest. Also, the relative biological effectiveness of neutrons with respect to the X-ray was investigated. On December 2, 1942, Fermi and associates at the University of Chicago accomplished a chain reaction from the fission of uranium atoms in a pile of graphite blocks. This remarkable discovery became the basis for manufacturing the atom bomb and the nuclear reactor. Today, most of the radioisotopes of biological and medical interest are produced in the nuclear reactor. In addition to this, the nuclear reactor serves as a source of neutrons of different energies that are being utilized for the study of radiation injuries.
Protontherapy to maintain local control of head and neck paragangliomas
Published in Acta Oncologica, 2023
Julie Chartier, Arnaud Beddok, Kim I. Cao, Loïc Feuvret, Philippe Herman, Stéphanie Bolle, Farid Goudjil, Elisabeth Sauvaget, Olivier Choussy, Rémi Dendale, Valentin Calugaru
Proton beam therapy was delivered by a cyclotron in the Institut Curie Proton therapy Center of Orsay, France (ICPO), with an energy of 201 MeV and a double-scattering technique. Magnetic resonance imaging (MRI) with thin-slice (2.0 or 3.0 mm) was required to delineate organs at risk and target volumes. Gross target volume delineation matched the visible tumor on MRI. The clinical target volume was built by adding to the gross target volume a margin of 3 to 5 mm, depending on the adjacency of organs at risk. A margin of 2 mm was added around the clinical target volume to create the planning target volume (PTV). Treatment plans were designed so that at least 95% of the PTV received at least 95% of the prescribed dose. The main dose contraints for organs at risk used are detailed in Supplementary Table 1 and were consistent with European recommendations [6]. All seventeen patients included in this retrospective study received a complete proton-only based treatment according to the double-scattering technique. Prescribed median dose for the PTV was 50.4 Gy RBE (Relative Biological Effectiveness = 1.1) (IQR 25–75%: 50.4–50.4 Gy) (1.8 Gy RBE/fraction). Median treatment duration was 42.0 days (IQR 25–75%: 40.0–43.0 days). Median number of fields was three. Treatment characteristics are detailed in Supplementary Table 2.
In Memorium
Published in Electromagnetic Biology and Medicine, 2023
Joseph R. Salvatore, Henry Lai
Abe is credited as the original developer of the ‘Ion Cyclotron Resonance’ hypothesis. One of the rare hypotheses in bioelectromagnetics on the mechanism of interaction between EMF and living organisms. It suggests the possibility of biological interaction of low-intensity extremely-low frequency and static EMF. This explains Abe’s interest in the geomagnetic field and his belief that biological effects are mostly caused by extremely-low frequency components of EMF. Numerous experiments have provided data that supports the ‘Ion Cyclotron Resonance’ mechanism. Since much knowledge has accumulated over the years on the cellular and molecular effects of electromagnetic fields and the recent concerns on the effects of ambient EMF on wildlife, there is a need to revisit Abe’s ‘Ion Cyclotron Resonance’ hypothesis.
Cohort profile – MSK radiation workers: a feasibility study to establish a deceased worker sub-cohort as part of a multicenter medical radiation worker component in the million person study of low-dose radiation health effects
Published in International Journal of Radiation Biology, 2022
Lawrence T. Dauer, Meghan Woods, Daniel Miodownik, Brian Serencsits, Brian Quinn, Michael Bellamy, Craig Yoder, Xiaolin Liang, John D. Boice, Jonine Bernstein
Later, with collaboration of the US Department of Energy and National Laboratories, a cyclotron (affectionately known as ‘Betsy’), one of the earliest hospital-based cyclotrons in the world and the first in the country, was installed in the SKI laboratory building in order to enable safe research and development and production of other radionuclides for imaging and therapy. Subsequent cyclotrons were installed, including a dual-beam instrument enabling both liquid and solid targets, as well as the most recent Radiochemistry and Cyclotron Facility which routinely produces positron-emitting radionuclides and develops and performs organic synthesis of both single-photon-emitting as well as positron-emitting radiotracers. These facilities were heavily supported by medical health physics engineering, design, and operational assistance to incorporate safety features while facilitating radionuclide production, research, and patient care.