scholarly journals Direct measurement of the 3-dimensional DNA lesion distribution induced by energetic charged particles in a mouse model tissue

2015 ◽  
Vol 112 (40) ◽  
pp. 12396-12401 ◽  
Author(s):  
Johanna Mirsch ◽  
Francesco Tommasino ◽  
Antonia Frohns ◽  
Sandro Conrad ◽  
Marco Durante ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Mouse Model ◽  
Dose Distribution ◽  
Biological Effects ◽  
Charged Particles ◽  
High Energy ◽  
X Rays ◽  
Particle Path ◽  
Modeling Approaches ◽  
Physical Measurements

Charged particles are increasingly used in cancer radiotherapy and contribute significantly to the natural radiation risk. The difference in the biological effects of high-energy charged particles compared with X-rays or γ-rays is determined largely by the spatial distribution of their energy deposition events. Part of the energy is deposited in a densely ionizing manner in the inner part of the track, with the remainder spread out more sparsely over the outer track region. Our knowledge about the dose distribution is derived solely from modeling approaches and physical measurements in inorganic material. Here we exploited the exceptional sensitivity of γH2AX foci technology and quantified the spatial distribution of DNA lesions induced by charged particles in a mouse model tissue. We observed that charged particles damage tissue nonhomogenously, with single cells receiving high doses and many other cells exposed to isolated damage resulting from high-energy secondary electrons. Using calibration experiments, we transformed the 3D lesion distribution into a dose distribution and compared it with predictions from modeling approaches. We obtained a radial dose distribution with sub-micrometer resolution that decreased with increasing distance to the particle path following a 1/r2 dependency. The analysis further revealed the existence of a background dose at larger distances from the particle path arising from overlapping dose deposition events from independent particles. Our study provides, to our knowledge, the first quantification of the spatial dose distribution of charged particles in biologically relevant material, and will serve as a benchmark for biophysical models that predict the biological effects of these particles.

Radiation detection materials for quality assurance and dose distribution assessment of small fields of high-energy X-rays

2020 ◽  
Vol 15 (04) ◽  
pp. P04001-P04001
Author(s):  
Sung Jin Noh ◽  
HyoJin Kim ◽  
Hyun Kim ◽  
Jeung kee Kim ◽  
Chi-Woong Mun ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Dose Distribution ◽  
Radiation Detection ◽  
High Energy ◽  
X Rays ◽  
Small Fields

Kinetics of nonhomogeneous chemical processes in tracks of high-energy charged particles

1990 ◽  
Vol 68 (9) ◽  
pp. 858-871 ◽  
Author(s):  
A. Hummel
Keyword(s):  
Spatial Distribution ◽  
Large Fraction ◽  
Charged Particles ◽  
Coulomb Field ◽  
High Energy ◽  
Transient Species ◽  
Charged Species ◽  
Solvent Molecules ◽  
Kinetics Of ◽  
Initial Spatial Distribution

High-energy charged particles, when slowing down in a molecular medium, lose their energy by electronic excitations and ionizations of molecules along their paths. If the secondary electrons that are formed as a result of the ionizations have sufficient energy, they give rise to further excitations and ionizations. In this way tracks of excited states, positive ions, and electrons are formed. The spatial distribution of the species initially formed in the track will change in time owing to diffusion; the charged species will also drift in each other's Coulomb field. In nonpolar systems the range of the Coulomb forces is very large (30 nm) and neutralization of the oppositely charged species in the track is a dominant process, which in turn leads to formation of excited molecules that generally decompose into reactive fragments. In polar liquids, like water, neutralization is less prevalent and a relatively large fraction of the charged species escapes from the Coulombic attraction. The transient species formed may react with one another and with molecules of the medium, either solvent molecules or solute molecules. The probability of the occurrence of these reactions depends on the initial spatial distribution of the reactive species in the track. The present state of the theory of the kinetics of the nonhomogeneous processes in tracks of high-energy charged particles, which relates the initial spatial distribution of the transient species in the track to the various experimental observables, will be discussed.

Burns by Ionizing and Non-Ionizing Radiation

2020 ◽  
Author(s):  
Giovanni Alcocer ◽  
Priscilla Alcocer ◽  
Carlos Marquez
Keyword(s):  
Ionizing Radiation ◽  
Visible Light ◽  
Gamma Rays ◽  
Biological Effects ◽  
High Energy ◽  
Low Energy ◽  
X Rays ◽  
Nuclear Accidents ◽  
Diagnostic Equipment ◽  
Nonionizing Radiation

Abstract This article consists of the study and investigative analysis of the effects of burns by radiation in humans. Cases of nuclear accidents, such as Chernobyl (ionizing radiation) and the effects of non-ionizing radiation such as infrared and microwave radiation are detailed. It is examined cases of injuries and burns by ionizing radiation due to irradiation (diagnostic equipment and medical treatment: X-rays, radiotherapy) or contamination (nuclear accidents, wars). Injuries and burns are also caused by nonionizing radiation, such as visible light (laser), ultraviolet, radiofrequency. There are numerous biological issues in the case of tissues, the ionizing radiation (ionizing particles and electromagnetic radiation: X-rays, gamma rays and high energy ultraviolet) can cause damage mainly in the DNA. This can cause mutations in its genetic code and cancer 5. In addition, damage to other tissues and organs can occur, as well as burns, erythema and lesions. The biological effects of nonionizing radiation are currently under investigation. Burns, erythema and lesions can also occur due to the following types of radiation: low energy ultraviolet, visible light, infrared, microwave, radiofrequency, electromagnetic fields. The purpose of this article is to provide an exhaustive analysis of all types of both ionizing and non-ionizing radiation and their effects on living beings. Finally, it is important to follow all safety and radiation protections against both ionizing and non-ionizing radiation.

scholarly journals Requirements for Designing an Effective Metallic Nanoparticle (NP)-Boosted Radiation Therapy (RT)

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3185
Author(s):  
Ioanna Tremi ◽  
Ellas Spyratou ◽  
Maria Souli ◽  
Efstathios P. Efstathopoulos ◽  
Mersini Makropoulou ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Metallic Nanoparticles ◽  
Biological Effects ◽  
Ion Beam ◽  
High Energy ◽  
Normal Tissue Complication Probability ◽  
X Rays ◽  
Beam Radiation ◽  
Particle Radiotherapy ◽  
High Let

Many different tumor-targeted strategies are under development worldwide to limit the side effects and improve the effectiveness of cancer therapies. One promising method is to enhance the radiosensitization of the cancer cells while reducing or maintaining the normal tissue complication probability during radiation therapy using metallic nanoparticles (NPs). Radiotherapy with MV photons is more commonly available and applied in cancer clinics than high LET particle radiotherapy, so the addition of high-Z NPs has the potential to further increase the efficacy of photon radiotherapy in terms of NP radiosensitization. Generally, when using X-rays, mainly the inner electron shells are ionized, which creates cascades of both low and high energy Auger electrons. When using high LET particles, mainly the outer shells are ionized, which give electrons with lower energies than when using X-rays. The amount of the produced low energy electrons is higher when exposing NPs to heavy charged particles than when exposing them to X-rays. Since ions traverse the material along tracks, and therefore give rise to a much more inhomogeneous dose distributions than X-rays, there might be a need to introduce a higher number of NPs when using ions compared to when using X-rays to create enough primary and secondary electrons to get the desired dose escalations. This raises the questions of toxicity. This paper provides a review of the fundamental processes controlling the outcome of metallic NP-boosted photon beam and ion beam radiation therapy and presents some experimental procedures to study the biological effects of NPs’ radiosensitization. The overview shows the need for more systematic studies of the behavior of NPs when exposed to different kinds of ionizing radiation before applying metallic-based NPs in clinical practice to improve the effect of IR therapy.

Dosimetry of cell-monolayers in multiwell plat

2009 ◽  
Vol 48 (03) ◽  
pp. 120-126 ◽  
Author(s):  
M. Andreeff ◽  
L. Oehme ◽  
J. Kotzerke ◽  
R. Freudenberg
Keyword(s):  
Dose Distribution ◽  
Absorbed Dose ◽  
High Energy ◽  
X Rays ◽  
Sphere Model ◽  
Cell Monolayers ◽  
Calculated Dose ◽  
The Mean ◽  
The Impact

Summary Aim: Irradiation of cells in-vitro with unsealed radionuclides is often carried out in cylindrical multi-well-plates. For calculation of the absorbed dose using the sphere model is common. This model assumes a spherical distribution of activity. However, by physical aspects a dose reduction in the peripheral area of the activity volume is expected and predicted especially for high-energy beta-emitting radionuclides. The impact on cellular dosimetry shall be depicted in this paper. Methods: The dose-distribution inside a multi-well-plate was calculated by convolving the dose distribution around a point source with a given activity. This was performed for the radionuclides I-131, Re-188 and Y-90 in wells of different sizes. For comparison the sphere dose was also calculated. Results: Depending on the beta-energy differences up to 40% between the mean calculated dose and the mean sphere dose were found, whereby calculated dose was always lower than the sphere model prediction. Furthermore a fall-off was calculated for the bottom-dose compared to dose in the centre. An analytical expression was revealed for the bottom-dose with respect to the filling level for three different wells. Conclusion: The shape of geometry and the influence on dose distribution must be considered especially at in-vitro exposure with low energy and short range beta-emitting radionuclides. There could be a great impact for exact dose estimation, which is especially necessary to know for comparison of different irradiation experiments (e.g. different radionuclides, various irradiation geometries or comparison with x-rays).

scholarly journals MCNPX simulations of the silicon carbide semiconductor detector response to fast neutrons from D–T nuclear reaction

2016 ◽  
Vol 44 ◽  
pp. 1660226 ◽  
Author(s):  
Katarína Sedlačková ◽  
Andrea Šagátová ◽  
Bohumír Zat'ko ◽  
Vladimír Nečas ◽  
Michael Solar ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Monte Carlo ◽  
Nuclear Reaction ◽  
Charged Particles ◽  
Radiation Detectors ◽  
High Energy ◽  
Nuclear Radiation ◽  
Fast Neutrons ◽  
Detector Response ◽  
X Rays

Silicon Carbide (SiC) has been long recognized as a suitable semiconductor material for use in nuclear radiation detectors of high-energy charged particles, gamma rays, X-rays and neutrons. The nuclear interactions occurring in the semiconductor are complex and can be quantified using a Monte Carlo-based computer code. In this work, the MCNPX (Monte Carlo N-Particle eXtended) code was employed to support detector design and analysis. MCNPX is widely used to simulate interaction of radiation with matter and supports the transport of 34 particle types including heavy ions in broad energy ranges. The code also supports complex 3D geometries and both nuclear data tables and physics models. In our model, monoenergetic neutrons from D–T nuclear reaction were assumed as a source of fast neutrons. Their energy varied between 16 and 18.2 MeV, according to the accelerating voltage of the deuterons participating in D–T reaction. First, the simulations were used to calculate the optimum thickness of the reactive film composed of High Density PolyEthylene (HDPE), which converts neutral particles to charged particles and thusly enhancing detection efficiency. The dependency of the optimal thickness of the HDPE layer on the energy of the incident neutrons has been shown for the inspected energy range. Further, from the energy deposited by secondary charged particles and recoiled ions, the detector response was modeled and the effect of the conversion layer on detector response was demonstrated. The results from the simulations were compared with experimental data obtained for a detector covered by a 600 and 1300 [Formula: see text]m thick conversion layer. Some limitations of the simulations using MCNPX code are also discussed.

scholarly journals Properties of Quantum Beams and Their Applications

2018 ◽  
Vol 10 (2) ◽  
pp. 30
Author(s):  
Naoaki Fukuda ◽  
Toshio Takiya ◽  
Min Han
Keyword(s):  
Biological Effects ◽  
High Energy ◽  
Industrial Applications ◽  
Alpha Particles ◽  
Future Research ◽  
X Rays ◽  
Beverage Containers ◽  
Wave Particle Duality ◽  
Food And Beverage ◽  
Energy Quantum

A conceptual formulation of quantum beams and their basic properties are presented. The present status and outlook of their industrial applications are also discussed. Quantum beams are highly directional energy beams consisting of quantum-mechanical particles characterized by wave-particle duality. They are a concept developed out of need in industry, and, together with quantum mechanics developed during the turn of the century, have been applied to semiconductor and medical industries. The quantum beams can be classified by penetrating or ionizing power. X-rays and neutron beams are classified into those with high penetrating power, and the beams of alpha particles are classified into those with high ionizing power. Electron beams fall in between, giving rise to their unique intermediate property. Their chemical and biological effects are used in modifying the properties of materials or sterilizing food and beverage containers. Finally, we discuss the importance of developing further advanced accelerator technologies which can produce high-energy quantum beams, which will be necessary to chart our future research in yet unknown areas of science. In doing so, profit should not be the only goal; contribution to a sustainable society should be considered as well.

scholarly journals Imaging with penetrating radiation for the study of small dynamic physical processes

2015 ◽  
Vol 33 (3) ◽  
pp. 425-431 ◽  
Author(s):  
F. E. Merrill
Keyword(s):  
Imaging Techniques ◽  
Charged Particles ◽  
High Energy ◽  
X Rays ◽  
High Energy Electron ◽  
Physical Processes ◽  
Proton Radiography ◽  
New Techniques ◽  
Maximum Information ◽  
Wide Range

AbstractSince Roentgen's discovery of X rays in the late 1800s the use of penetrating radiation to form images has become a part of our everyday life as well as providing a useful tool for the scientific study of processes that have been previously impossible to measure. This can include the study of processes that are too deeply embedded in opaque materials for direct observation, or that occur on a length or time scale smaller than otherwise can be easily measured. As technologies to generate penetrating radiation and quickly collect images have matured, new techniques have emerged to measure processes that have been hidden for many years. One example is advances in flash radiography using charged particles as radiographic probes, including proton radiography and electron radiography. Recently the successful commissioning of proton microscope systems has provided remarkable improvements in spatial resolution. These techniques are being implemented for applications with electron radiography. With the evolution of these new techniques comes the opportunity to choose the probe that provides the maximum information for the desired measurement. This paper describes these new imaging techniques, predicts the capabilities of high-energy electron radiography, and provides a guide for identifying the optimal probe for a wide range of measurements.

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