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New Trends
Published in Vlado Valković, Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
Now, however, about half of the population exposure is considered to originate from radon. This gaseous radioactive isotope is now recognized as being much more pervasive than previously acknowledged and a problem that was considered to be confined to special groups (such as uranium miners) has now confronted the community at large. Recognition that radon is more widespread than previously thought, along with a longstanding recognition of the biological effectiveness of alpha-particle radiation has led to estimates of significant numbers of human cancers being attributable to the alpha-particle irradiations from the breakdown of radon daughters. Such estimates are, however, fraught with considerable uncertainty and meaningful assessments of risk can only come about after a broad understanding of the biological effects of individual alpha particles over the LET range encompassed by the breakdown products of the radon daughters.
Kill or Cure
Published in Alan Perkins, Life and Death Rays, 2021
Alpha particles are the heaviest and largest form of particle radiation containing two neutrons and two protons. This is the same as the nucleus of the helium atom and so has a positive charge. Being large they do not penetrate far into matter and can be stopped by a thin sheet of paper. However, alpha particles can deposit a large amount of energy in a small volume of material. If this energy is absorbed by tissues of the body it can cause a great deal of biological damage, for example by cutting strands of DNA in cellular chromosomes or by producing chemically active free radicals in tissues, both of which can cause tumours to develop.
Our Radiation Environment
Published in T. D. Luckey, Radiation Hormesis, 2020
Q for alpha rays, neutron, and proton beams varies between 2 and 400 times that of the low LET rays; generally, 1 Gy = 2 to 40 Sv for particle rays.515,516 For thermal (slow) neutrons Q = 5 (2 to 8). For alpha rays, protons, other nuclei, and fission (fast) neutrons Q = 20 (5 to 200).660 Relatively few experiments and well-studied human experiences are available regarding particle radiation. The emphasis upon uranium, thorium, and their progeny, such as radon, has involved their internal disintegrations, particularly in the lungs. Although these radionuclides and their progeny also release some beta and gamma rays, their release of alpha rays deserves full emphasis.
Dosimetric comparison between carbon, proton and photon radiation for renal retroperitoneal soft tissue sarcoma recurrence or metastasis after radical nephrectomy
Published in International Journal of Radiation Biology, 2022
Xue Ming, Weiwei Wang, Kambiz Shahnazi, Jiayao Sun, Qing Zhang, Ping Li, Zhengshan Hong, Yinxiangzi Sheng
Charged particle radiation is the emerging attempt for the management of RSTS (Tuan et al. 2014). Several clinical trials have been conducted to explore the role of adjunctive radiotherapy for RSTS (Tuan et al. 2014), including IMRT, proton, and carbon radiation. Since renal RSTS recurrence or metastasis (RRSTSRM) is of rare incidence, few studies have reported the dosimetric comparison between multiple radiation techniques for RRSTSRM after radical nephrectomy. Also, limited researches have reported the quantitative correlations between the biological benefits and the dosimetric difference between the various radiation techniques, especially for the cases whose lesions are adjacent to the duodenum. In this study, four radiation techniques, including intensity-modulated carbon therapy (IMCT), intensity-modulated proton therapy (IMPT), intensity-modulated photon therapy (IMRT) and volumetric-modulated arc therapy (VMAT), were utilized to assess the dosimetric difference of the targets, organs at risk (OARs) and normal tissues. The dosimetric difference was also assessed among several sub-groups according to the distance between the targets and the duodenum of the patients. Two treatment planning systems (TPS) were occupied to evaluate the robustness of the carbon and proton plans. Also, the normal tissue complication probability (NTCP) for the OARs was estimated to explore the biological benefits between multiple radiation modalities. Therefore, the present study aimed at the treatment strategy support for a preferable selection of radiation modality for the RRSTSRM patients after radical nephrectomy.
Construction and evaluation of an α-particle-irradiation exposure apparatus
Published in International Journal of Radiation Biology, 2021
Zacharenia Nikitaki, Evangelia Choulilitsa, Spyridon A. Kalospyros, Sofia Kaisaridi, Georgia I. Terzoudi, Mike Kokkoris, Alexandros G. Georgakilas
Ionizing radiation (IR) induces a variety of lesions in the DNA, like base or sugar damage, alkali-labile sites, single strand breaks (SSBs) and double-strand breaks (DSBs)-with the latter considered the most lethal ones. These lesions result from direct hit of the genetic molecule or indirectly due to free radicals attack (Georgakilas 2000; Boss 2014). Alpha particle radiation, characterized as a high LET -in contrast to low-LET X-rays- causes biological effects with less dependency on the dose rate or the cell cycle stage (NuPECC 2014). Additionally, the type of the DNA lesions caused by α- particles is less susceptible to the equivalent DNA repair mechanisms (NuPECC 2014). There is also plenty of evidence showing that IR and especially the high LET one such as α-particles, are capable of producing highly clustered (complex) DNA damage, which is closely connected to IR’s major lethal or mutagenic effects (Mavragani 2019). A cluster of lesions consisting of two or more types of damage in a small DNA region of a few base pairs, is widely considered to be more challenging to repair for the cell than individual lesions, and thus resulting in mutagenesis, genomic instability and cell death (Georgakilas 2013).
Role of DNA damage and repair in radiation cancer therapy: a current update and a look to the future
Published in International Journal of Radiation Biology, 2020
Jingya Liu, Kun Bi, Run Yang, Hongxia Li, Zacharenia Nikitaki, Li Chang
The most well-studied ionizing rays (photons) are the X- and γ-rays widely used for various technological or medical applications, as well as particle radiation like α particles, protons, carbon ions etc. Many years ago, it has been shown that 238Pu emitted α-particles (range of ∼20 μm; peak energy, 3.26 MeV; LET at the position of the cells, 121.4 keV/μm) induce presumably dense (clustered) DNA damage, complex genetic changes in irradiated human cells (Singleton et al. 2002). On the other hand, X- or γ- electromagnetic radiation, although causes ionizations quite easily, they are not so dense compared to those caused by particle radiation, but they are still destructive for any living matter, like cellular DNA (Sutherland et al. 2001, 2002). Steel, lead or concrete (or a combination) needs to be used for shielding electromagnetic IR. It is much more invasive than particle radiations and it poses a risk of external and internal exposure.