China
Africa
Explore chapters and articles related to this topic
Introduction to Ion Beam Analysis
Published in Yoshiaki Kato, Zenpachi Ogumi, José Manuel Perlado Martín, Lithium-Ion Batteries, 2019
Tomihiro Kamiya, Takahiro Satoh, Akiyoshi Yamazaki
Ions are usually classified by their mass numbers as light ions and heavy ions. Light ions usually refer to the ions with mass numbers of less than 4, for example, proton, deuterium ion (deuteron), and helium ion (α particle). Heavy ions refer to various ions of elements with mass numbers larger than 4. There is another classification: monoatomic ions, molecular ions, and cluster ions. The cluster ion beam is a group of large number of atoms ionized and accelerated as an ion beam. Interaction of the cluster ions with matter is very different from the interaction of the monoatomic ions. Many practical applications have been initiated due to their unique irradiation effects, especially on material surface modification by nuclear interaction with low-energy cluster ion beams. A cluster ion beam with MeV energy has been made available in recent years [38]. Clarification of the peculiar mechanisms of its interaction with matter and the applicability to the analysis technology are subjects of intensive research.
Why Particle Therapy Rather than Photon Therapy or How to Integrate the Decision into Multimodal Management
Published in Manjit Dosanjh, Jacques Bernier, Advances in Particle Therapy, 2018
Joachim Widder, Richard Pötter
There is unanimous agreement that the proton (or heavy ion) dose profile enabling reduction of dose outside the target volume (together with eventually increasing the tumour effect within the target) is why ions might be the better beams to deliver therapeutic radiation than photons. Why has this not been taken seriously enough to actually demonstrate instead of continually announcing superiority based on quite weak proof? The reasons why there is still a painful lack of evidence for ion beam therapy are many.
Recent Advances in Sulfate- and Sulfide-Based Phosphors Used in Versatile Applications
Published in Sanjay J. Dhoble, B. Deva Prasad Raju, Vijay Singh, Phosphors Synthesis and Applications, 2018
Radiations are omnipresent in the atmosphere in the form of energy that traverses as electromagnetic waves or high-speed particles. The ionizing radiations are often used for the treatment of cancerous tumors and other heterogeneous classes of diseases. However, incorrect exposure to ionizing radiations may prove fatal, and hence, knowledge of the absorbed dose of radiation is much important for increasing the efficiency of the treatment. Heavy-ion therapy is the use of particles more massive than protons or neutrons, such as carbon ions [3]. The dosimetry of charged particle beams in cancer diagnosis and therapy has taken a decisive lead to meet the demands of an accurate calibration of radiotherapy sources. TL is the radiation-analyzing process that is often implemented to determine the amount of dose absorbed for a specific duration of the radiation exposure. This phenomenon includes heating of the irradiated material, due to which the energy stored in the crystal/material is released with the emission of light, and the intensity of the emitted light as a function of temperature is related to the dose absorbed by material before readout [4]. TL is the most common technique used for the dosimetry of different ionizing radiations, while considering the objectives like radiation protection monitoring. Lattice defects in the crystals can be studied by TL analysis [5]. Thermoluminescent dosimeters (TLDs) have been in service, owing to their small size and easy handling. The suitability and applicability of a TL material for dosimetric purposes depends on dosimetric characteristics such as the nature of the glow curve, TL response as a function of dose, energy dependence, and stability of the TL signal as a function of time [6]. TLD materials are expected to have a low photon energy dependence of response. Tissue-equivalent phosphors (effective atomic number of tissue Zeff = 7.4), or approximated tissue equivalent, should be used for personal and medical applications to avoid energy corrections [7]. Although fluorides are the most commonly used TLDs, their susceptibility to heat treatments and complicated glow curve structures posed some difficulties in dosimetry. The next in category are the sulfate-based TL materials, which are widely studied because of their well-desired characteristics like a high- temperature glow peak and high sensitivity toward the absorbed dose. The major problem with sulfate-based dosimeters is that they are not tissue equivalent (low Z) and so efforts are being made to improve their tissue equivalence [8].
Investigation of tissue equivalence of phantom biomaterials in 4He heavy ion therapy
Published in Radiation Effects and Defects in Solids, 2023
Today, heavy ion therapy, such as proton and carbon, is a very popular method for cancer treatment (1–3). Especially within the Bragg peak, heavy ions such as carbon have low linear energy transfer (LET) protons and a high LET as they accumulate more energy per unit distance (μm) than their photons (4). Despite these advantages, in recent years, it has encouraged the investigation of new ions such as helium (4He) ions in clinical cases where protons and carbon ions are not ideally suited (5). 4He ions show intermediate properties between proton and carbon ions in terms of radiation physics (lateral scattering and fragmentation) and radiobiology (6). In the heavy ion therapy project at Lawrence Berkeley National Laboratory, many patients were treated with 4He ions between 1975 and 1992 (7). Heidelberger planned to diversify the type of ion beam by launching patient therapy with 4He ions, recently screened at the Heidelberger Ionenstrahl-Therapiesentrum in Germany (5). In the Nuclear Information and Resource Service, Japan, many ion therapy concepts containing 4He ions are currently established (8), and also the National Center of Oncological Hadrontherapy and MedAustron have found that 4He is suitable for ion therapy considering its technical characteristics (9).
Research on photogrammetry-based positioning of heavy ion radiotherapy and tumor target monitoring
Published in Radiation Effects and Defects in Solids, 2021
W. J. Chen, Y. Q. Yang, Y. J. Zheng, B. Zhang, S. M. Wang, J. D. Yuan, G. Z. Sun, X. D. Zhang, L. S. Yan
Heavy ion radiotherapy is different from traditional one with photons (1). Since heavy ion beams could cast unique physical and biological effects, they become more advantageous when treating malignant tumors (2,3). As shown in Figure 1, the Bragg peak of the heavy ion beam demonstrates the beam current can reach its maximum dose at the tumor tissue, so that the patient’s normal tissue shall not receive excessive doses and form new lesions afterwards (4,5). Therefore, the requirement on positioning precision for patients receiving heavy ion radiotherapy is stricter than that of conventional radiotherapy.