Charged Particle Irradiation Research Articles

Simulation of the direct production of 99mTc at a small cyclotron

Usually 99mTc is produced indirectly through generator 99Mo/99mTc. In the present study, the direct production of this radioisotope by charged particle irradiation was investigated using Monte Carlo method. After scouting of the reactions that produce 99mTc, excitation functions of these reactions were predicted by optical model components in the TALYS-1.6 code. Suitable energy range of projectile for this production was selected by spotting of maximum cross section and minimum impurity due to other emission channels. Then target geometry was designed based on stopping power calculation by the SRIM code. Thick target yield of 100Mo(p,2n)99mTc, 98Mo(p,γ)99mTc and natMo(p,x)99mTc reactions was predicted by the result of excitation function and stopping power calculations. Finally, 100Mo(p,2n)99mTc reaction was selected as a primary reaction for the direct production of 99mTc and its process was simulated by employing the MCNPX code to calculate the energy distribution of proton in the 100Mo target body and estimation of residual nuclei during irradiation. Good agreement was obtained between the experimental, the theoretical, and the simulation-based (analytical and directly) production yields. This study demonstrated that Monte Carlo provides a method for the design and optimization of targets for the radionuclide production purposes.

ATM Alters the Otherwise Robust Chromatin Mobility at Sites of DNA Double-Strand Breaks (DSBs) in Human Cells

Ionizing radiation induces DNA double strand breaks (DSBs) which can lead to the formation of chromosome rearrangements through error prone repair. In mammalian cells the positional stability of chromatin contributes to the maintenance of genome integrity. DSBs exhibit only a small, submicron scale diffusive mobility, but a slight increase in the mobility of chromatin domains by the induction of DSBs might influence repair fidelity and the formation of translocations. The radiation-induced local DNA decondensation in the vicinity of DSBs is one factor potentially enhancing the mobility of DSB-containing chromatin domains. Therefore in this study we focus on the influence of different chromatin modifying proteins, known to be activated by the DNA damage response, on the mobility of DSBs. IRIF (ionizing radiation induced foci) in U2OS cells stably expressing 53BP1-GFP were used as a surrogate marker of DSBs. Low angle charged particle irradiation, known to trigger a pronounced DNA decondensation, was used for the defined induction of linear tracks of IRIF. Our results show that movement of IRIF is independent of the investigated chromatin modifying proteins like ACF1 or PARP1 and PARG. Also depletion of proteins that tether DNA strands like MRE11 and cohesin did not alter IRIF dynamics significantly. Inhibition of ATM, a key component of DNA damage response signaling, resulted in a pronounced confinement of DSB mobility, which might be attributed to a diminished radiation induced decondensation. This confinement following ATM inhibition was confirmed using X-rays, proving that this effect is not restricted to densely ionizing radiation. In conclusion, repair sites of DSBs exhibit a limited mobility on a small spatial scale that is mainly unaffected by depletion of single remodeling or DNA tethering proteins. However, it relies on functional ATM kinase which is considered to influence the chromatin structure after irradiation.

Spatiotemporal kinetics of γ-H2AX protein on charged particles induced DNA damage

Abstract In several researches, it has been demonstrated that charged particles can induce more complex DNA damages. These complex damages have higher ability to cause the cell death or cell carcinogenesis. For this reason, clarifying the DNA repair mechanism after charged particle irradiation plays an important role in the development of charged particle therapy and space exploration. Unfortunately, the detail spatiotemporal kinetic of DNA damage repair is still unclear. In this study, we used γ-H2AX protein to investigate the spatiotemporal kinetics of DNA double strand breaks in alpha-particle irradiated HeLa cells. The result shows that the intensity of γ-H2AX foci increased gradually, and reached to its maximum at 30 min after irradiation. A good linear relationship can be observed between foci intensity and radiation dose. After 30 min, the γ-H2AX foci intensity was decreased with time passed, but remained a large portion (∼50%) at 48 h passed. The data show that the dissolution rate of γ-H2AX foci agreed with two components DNA repairing model. These results suggest that charged particles can induce more complex DNA damages and causing the retardation of DNA repair.

Effects of proton radiation on evoked and spontaneous neuronal activity in the hippocampus of APP/PSEN1 transgenic mice

Ground-based studies on space radiation indicate that exposure to charged particle radiation at relatively low doses may impair neuronal functions. Decrements in excitatory synaptic transmission and plasticity in the hippocampus have been previously reported in mouse brains irradiated with iron nuclei, but relatively little is known about the effects of protons on the synaptic activity in the hippocampus. Behavioral and neurophysiological decrements in irradiated subjects are also commonly observed in Alzheimer's disease (AD), and we hypothesized that irradiation with protons may exacerbate AD-like neurodegenerative pathology. We used transgenic (TG) mice with AD-like neurodegeneration to test whether whole-body irradiation with protons (150 MeV; 0.1, 0.5, 1 Gy) accelerates the onset of AD and/or exacerbates synaptic impairments. We measured evoked excitatory synaptic potentials, synaptic plasticity and spontaneous oscillations in hippocampal slices prepared from APP/PSEN1 double TG mice (males only) at 6 and 9 months post-irradiation.Our electrophysiological recordings indicate that most of the radiation-induced synaptic decrements can be observed at 9 months rather than 6 months post-irradiation and they are differently expressed in TG and wild-type (WT) mice. Presynaptic excitability evaluated by the amplitude of fiber volleys was significantly increased in non-irradiated TG mice when compared with non-irradiated WT mice, and irradiation did not cause further alterations. The post-synaptic, dendritic excitability, evaluated by the initial slope of the excitatory post-synaptic potentials (EPSPs), was reduced in TG mice exposed to 0.5 Gy, but increased relative to WT mice at the same dose. Interestingly, the suppressive effect on EPSP in TG mice was not observed at 1 Gy. Post-synaptic firing of action potentials, evaluated by the amplitude of population spikes (PS), was increased in non-irradiated TG mice when compared with WT controls. However, these increases were significantly reduced by irradiation at 0.1 and 1 Gy. Long-term potentiation of the EPSPs, a widely used electrophysiological correlate of memory formation, was not significantly affected by irradiation. Last, in WT mice, we observed a significant radiation-induced decrease in the frequency of epileptiform oscillations in the CA3–CA1 network triggered by reduced concentration of extracellular magnesium. These spontaneous waveforms (SW) are reminiscent of ‘sharp-wave/ripple complexes’ that have been associated with memory consolidation in the hippocampus. Interestingly, in the behavioral part of our project, irradiation impaired hippocampal learning in WT mice, while it did not affect performance in TG mice [ 1]. This may indicate altered memory consolidation in irradiated WT mice, where we observed significant negative correlation between SW and increased swim distance in water maze. Our data indicate that irradiation with protons at low doses may differently affect synaptic parameters in WT and APP/PSEN1 TG mice. Thus, different neurological or cognitive decrements may be expected in normal subjects relative to those prone to AD-like pathology. The most prominent radiation-induced decrements in TG mice were reduced dendritic excitability and firing of CA1 neurons. The reduction in PS amplitudes in TG mice suggests that proton radiation may impair communication of the hippocampal neurons with other brain areas. Memory formation and consolidation processes in TG mice are likely not further affected by the irradiation.

The effects of low doses of proton, iron or silicon radiation on spatial learning in a mouse model of Alzheimer's disease

Astronauts venturing outside low-Earth orbit risk exposure to charged particle radiation that can cause neurological deficits via oxidative stress, synaptic changes, altered neurogenesis and neuroinflammation. Because these responses are similar to those observed in age-related neurodegenerative diseases, we hypothesized that individuals with a propensity toward developing Alzheimer's disease (AD) would be more adversely affected by such exposure. To test this hypothesis, we exposed young double transgenic (tg) APP/PSEN1 mice (a commercially available strain engineered to develop AD-like neuropathology) and their wild-type (wt) counterparts to low doses of proton radiation (150 MeV/n, whole body). Spatial learning ability, a sensitive behavioral marker of hippocampal damage, was assessed using the water maze (WM) prior to exposure, then 3 and 6 months post-irradiation. Results showed that wt mice outperformed tg mice at each time-point, and irradiation of tg mice at doses 0.1, 0.5 and 1 Gy did not induce spatial learning deficits. However, deficits were observed in wt mice exposed to 0.5 Gy compared with 0 Gy wt controls at 6 months post-irradiation. Specifically, the 0.5 Gy group performed worse than the control group during the reversal learning phase of the WM, when the platform was switched to a new location (P < 0.02). The irradiated mice were unable to alter their search strategy and often perseverated on the previous platform location. Reduced reversal learning demonstrates cognitive inflexibility in novel situations and may be indicative of hippocampal memory system dysfunction.In a follow-up study to assess the effects of high-LET particles on AD-like pathology, we exposed tg mice to low doses (0.1, 0.5 or 1 Gy) of either iron (600 MeV/n) or silicon (250 MeV/n) radiation and assessed the effects on spatial learning ability in the WM at 3 and 6 months post-irradiation. Mice exposed to 1 Gy of iron radiation performed better than 0 Gy tg controls in the WM at the 6 month time-point (P < 0.03). Conversely, mice exposed to 0.1 Gy of silicon radiation performed significantly worse than controls in the WM at the 3 month time-point (P < 0.02), but these deficits had ameliorated by 6 months. Mice exposed to 0.5 and 1 Gy of silicon radiation exhibited changes similar to those observed in the 0.1 Gy group, but the decrements did not reach statistical significance. These data suggest that exposure to low doses of iron radiation decreases the behavioral effects of AD-like neuropathology in the long-term, while silicon radiation exacerbates short-term cognitive impairment in individuals with a propensity for such pathology. Electrophysiological and immunohistochemical data are forthcoming, and will aid in elucidating potential mechanisms responsible for the observed effects.Altogether, these results suggest that various types of particles induce different behavioral effects at low doses in APP/PSEN1 tg mice. Namely, proton radiation was found to have no effect on performance, iron radiation improved performance in the long-term and silicon radiation temporarily impaired performance. The finding that low doses of iron and silicon radiation alter performance on a hippocampus-dependent task could have implications for astronauts with a predisposition to developing AD-like neurodegenerative changes who travel on extended missions outside Earth's magnetosphere.

Review of Session 7: non-cancer risk

Astronauts in space and cancer patients being treated with ion beam radiotherapy can be exposed to charged particle radiations including energetic protons and heavy ions. These charged particles may be more effective than photons in inducing cancer as well as in causing non-cancer effects. The latter include acute damage from large solar particle events to the blood-forming organs and skin, acute and (from heavier ions) late damage to the central nervous system, and late degenerative damage to the lens of the eye and the cardiovascular, circulatory and respiratory systems. The presentations in this session discussed a number of non-cancer effects of protons and heavier charged particles including acute hematopoietic alterations, potentially detrimental cardiovascular and circulatory effects, and lifespan shortening.

Analysis of the charged particle radiation effect for a CubeSat transiting from Earth to Mars

This paper presents a computational estimation of the total ionizing dose from protons and electrons in the Earth's magnetosphere and interplanetary space for a hypothetical CubeSat transiting from Earth to Mars. An initial hyperbolic escape of the spacecraft from Earth's gravitation is assumed, followed by an elliptical transfer from Earth to Mars under the Sun's gravitation. The rapid traversal of the Earth's radiation belt yields a smaller ionizing dose, whereas high-energy solar protons in the interplanetary space have the greatest effect on the ionizing dose during the transfer between the planets. Variation in the heliocentric distance of the spacecraft is considered in the calculation. Calculation of the shielding distributions with Geant4 and the transport of the ionizing particles across the obtained distributions yields an estimation of the total ionizing dose as a function of position within the spacecraft as well as statistical confidence levels. With a moderate confidence level, this calculation shows that a practical exploration of Mars with a CubeSat is possible in terms of the expected total ionizing dose.

Damage Effects of Charged Particles Irradiation on An Epoxy Resin

In this study, the mass loss effect and the related outgassing of 5224 epoxy resin have been investigated. Subsequent irradiation of 160 keV proton and electron with the fluences ranging from 5.4×1015 to 3.75×1016 cm−2 in vacuum (1.2×10−5 Pa) was performed. The increase of the fluence of proton or electron made the mass loss ratios increase, then level off. The surface roughness of specimens increased followed by augmenting as the function of fluence. The outgassing rate of most molecule ions reached to maximum under the fluences ranging from 5.4×1015 cm−2 to 1.18×1016 cm−2. With further increasing fluence, the outgassing rate decreased owing to the effects of carbon enrichment or even carbonification developed gradually on the surface layer of the irradiated specimens. It is suggested that two events might play vital roles in dominating the magnitude of the outgassing rates: one is the formation of molecule ions; the other is the enrichment of carbon on the surface layer.

Tunneling of Charged Massive Particles from Taub-NUT-Reissner-Nordström-AdS Black Holes

We apply the null-geodesic method to investigate tunneling radiation of charged and magnetized massive particles from Taub-NUT-Reissner-Nordstrom black holes endowed with electric as well as magnetic charges in Anti-de Sitter (AdS) spaces. The geodesics of charged massive particle tunneling from the black hole is not lightlike, but can be determined by the phase velocity. We find that the tunneling rate is related to the difference of Bekenstein-Hawking entropies of the black hole before and after the emission of particles. The entropy differs from just a quarter area at the horizon of black holes with NUT parameter. The emission spectrum is not precisely thermal anymore and the deviation from the precisely thermal spectrum can bring some information out, which can be treated as an explanation to the information loss paradox. The result can also be treated as a quantum-corrected radiation temperature, which is dependent on the black hole background and the radiation particle’s energy and charges.

Lunar weather measurements at three Apollo sites 1969–1976

AbstractThe first lunar weather stations, matchbox‐sized, 270 g Apollo Dust Detector Experiments about 100 cm above the surface of the Moon near Apollo 12, 14, and 15 landing sites, measured dust accretion, charged particle radiation, and temperature changes—three environmental factors proved during Apollo to affect technical systems deployed on the Moon. Degradation of seven horizontal solar cells was measured every lunar daytime from 1969 to 1976. The anomalously intense August 1972 solar particle event (SPE) degraded three covered cells by less than 1%, while two cells desensitized by intense preirradiation showed no measurable effects. Although independent studies estimated the long‐term fluence bombarding the cells was less than half that of the August SPE, long‐term gradual degradation of five covered cells (normalized to 2000 days) was an order of magnitude greater, between 4% and 10%. If the long‐term effects were totally caused by dust, with articulated caveats including simulated (maria) Minnesota Lunar Simulant‐1 dust particles with diameters 20 to 38 µm, this provides the first direct measured long‐term net accretion of dust with an upper limit of order 100 µg cm−2 yr−1, equivalent to a layer 1 mm thick in 1000 years, but it may be significantly less. Two bare cells were abruptly degraded by 7% during the August SPE, however long‐term they measured additional damage of 29% and 24%, indicating a long‐neglected suite of low‐energy radiation, posing risks for bare materials exposed on the surface of the Moon.

Low level irradiation in mice can lead to enhanced trabecular bone morphology

Charged particle radiation such as iron ions and their secondary fragmentation products are of particular concern to the skeleton due to their high charge and energy deposition. However, little is known about the long-term effects of these particles on trabecular and cortical bone morphology when applied at relatively low levels. We hypothesized that even a 4.4 cGy dose of a complex secondary iron ion radiation field will compromise skeletal quantity and architecture in adult mice. One year after radiation exposure and compared to age-matched controls, 4.4 cGy irradiated mice had 51 % more trabecular bone, 56 % greater trabecular bone volume fraction, 16 % greater trabecular number, and 17 % less trabecular separation in the distal metaphysis of the femur. Similar to the metaphysis, trabecular bone of the distal femoral epiphysis in 4.4 cGy mice had 33 % more trabecular bone, 31 % greater trabecular bone volume fraction, and a 33 % smaller structural model index. Cortical bone morphology, whole bone mechanical properties, and lower leg muscle mass were unaffected. When compared to two additional groups, irradiated at either 8.9 or 17.8 cGy, a (negative) dose response relationship was observed for trabecular bone in the metaphysis but not in the epiphysis. In contrast to our original hypothesis, these data indicated that a secondary field of low-level, high-linear energy transfer iron radiation may cause long-term augmentation, rather than deterioration, of trabecular bone in the femoral metaphysis and epiphysis of mice.

Position statement on ethics, equipoise and research on charged particle radiation therapy

The use of charged-particle radiation therapy (CPRT) is an increasingly important development in the treatment of cancer. One of the most pressing controversies about the use of this technology is...

Functional Consequences of Radiation-Induced Oxidative Stress in Cultured Neural Stem Cells and the Brain Exposed to Charged Particle Irradiation

Redox homeostasis is critical in regulating the fate and function of multipotent cells in the central nervous system (CNS). Here, we investigated whether low dose charged particle irradiation could elicit oxidative stress in neural stem and precursor cells and whether radiation-induced changes in redox metabolism would coincide with cognitive impairment. Low doses (<1 Gy) of charged particles caused an acute and persistent oxidative stress. Early after (<1 week) irradiation, increased levels of reactive oxygen and nitrogen species were generally dose responsive, but were less dependent on dose weeks to months thereafter. Exposure to ion fluences resulting in less than one ion traversal per cell was sufficient to elicit radiation-induced oxidative stress. Whole body irradiation triggered a compensatory response in the rodent brain that led to a significant increase in antioxidant capacity 2 weeks following exposure, before returning to background levels at week 4. Low dose irradiation was also found to significantly impair novel object recognition in mice 2 and 12 weeks following irradiation. Data provide evidence that acute exposure of neural stem cells and the CNS to very low doses and fluences of charged particles can elicit a persisting oxidative stress lasting weeks to months that is associated with impaired cognition. Exposure to low doses of charged particles causes a persistent oxidative stress and cognitive impairment over protracted times. Data suggest that astronauts subjected to space radiation may develop a heightened risk for mission critical performance decrements in space, along with a risk of developing long-term neurocognitive sequelae.

SU-E-T-484: A Closed Parameterization of Microscopic Damage as a Function of Energy in Dose Deposition by Charged Particles

Purpose: To present the derivation and application of a closed formalism for the impact of charged particle radiation on damage induced in DNA. The formalism is valid for all types of charged particles and due to its closed nature is suited to provide fast conversion of dose to DNA‐damage. As photon treatments can be reduced to energy deposition by electrons it is also possible to calculate damage for classical radiation treatments. Methods: A simple geometrical model allows to parameterize the impact of charged particles in terms of single and double strand breaks. The parameters of the model contain: double strand threshold (i.e. the maximal distance two single lesions can have to be categorized as a double strand break), the diameter of the DNA‐strand, and a scaling factor describing distance between ionizing collisions in terms of particle energy. The model is validated using microdosimetric Monte Carlo calculations for electrons and protons. Finally, example applications are constructed calculating Relative Biological Effectratios for proton therapy compared to a therapeutic 6MV beam. Results: For both protons and electrons the model fits the Monte Carlo calculations almost perfectly as assessed by a χ2‐test. The energy scaling factor seems to be the only difference between the modalities of protons and electrons. The RBE‐factor for a mono‐energetic proton beam varies depending on the depth and is of the order of 1.1 rising to almost 2 at the Bragg peak. Conclusions: We have shown that it is possible to provide a generalized expression parameterizing the DNA‐damage induced by different modalities, indicating that the change in biological effect is mainly governed by geometrical considerations rather than a biological impact.

Comparison of human chordoma cell-kill for 290 MeV/n carbon ions versus 70 MeV protons in vitro

BackgroundWhile the pace of commissioning of new charged particle radiation therapy facilities is accelerating worldwide, biological data pertaining to chordomas, theoretically and clinically optimally suited targets for particle radiotherapy, are still lacking. In spite of the numerous clinical reports of successful treatment of these malignancies with this modality, the characterization of this malignancy remains hampered by its characteristic slow cell growth, particularly in vitro.MethodsCellular lethality of U-CH1-N cells in response to different qualities of radiation was compared with immediate plating after radiation or as previously reported using the multilayered OptiCell™ system. The OptiCell™ system was used to evaluate cellular lethality over a broad dose-depth deposition range of particle radiation to anatomically mimic the clinical setting. Cells were irradiated with either 290 MeV/n accelerated carbon ions or 70 MeV accelerated protons and photons and evaluated through colony formation assays at a single position or at each depth, depending on the system.ResultsThere was a cell killing of approximately 20–40% for all radiation qualities in the OptiCell™ system in which chordoma cells are herein described as more radiation sensitive than regular colony formation assay. The relative biological effectiveness values were, however, similar in both in vitro systems for any given radiation quality. Relative biological effectiveness values of proton was 0.89, of 13–20 keV/μm carbon ions was 0.85, of 20–30 keV/μm carbon ions was 1.27, and >30 keV/μm carbon ions was 1.69. Carbon-ions killed cells depending on both the dose and the LET, while protons depended on the dose alone in the condition of our study. This is the first report and characterization of a direct comparison between the effects of charged particle carbon ions versus protons for a chordoma cell line in vitro. Our results support a potentially superior therapeutic value of carbon particle irradiation in chordoma patients.ConclusionCarbon ion therapy may have an advantage for chordoma radiotherapy because of higher cell-killing effect with high LET doses from biological observation in this study.

Charged particle detection performances of CMOS pixel sensors produced in a [formula omitted] process with a high resistivity epitaxial layer

The apparatus of the ALICE experiment at CERN will be upgraded in 2017/18 during the second long shutdown of the LHC (LS2). A major motivation for this upgrade is to extend the physics reach for charmed and beauty particles down to low transverse momenta. This requires a substantial improvement of the spatial resolution and the data rate capability of the ALICE Inner Tracking System (ITS). To achieve this goal, the new ITS will be equipped with 50μm thin CMOS Pixel Sensors (CPS) covering either the three innermost layers or all the 7 layers of the detector. The CPS being developed for the ITS upgrade at IPHC (Strasbourg) is derived from the MIMOSA 28 sensor realised for the STAR-PXL at RHIC in a 0.35μm CMOS process. In order to satisfy the ITS upgrade requirements in terms of readout speed and radiation tolerance, a CMOS process with a reduced feature size and a high resistivity epitaxial layer should be exploited. In this respect, the charged particle detection performance and radiation hardness of the TowerJazz0.18μm CMOS process were studied with the help of the first prototype chip MIMOSA 32. The beam tests performed with negative pions of 120GeV/c at the CERN-SPS allowed to measure a signal-to-noise ratio (SNR) for the non-irradiated chip in the range between 22 and 32 depending on the pixel design. The chip irradiated with the combined dose of 1MRad and 1013neq/cm2 was observed to yield an SNR ranging between 11 and 23 for coolant temperatures varying from 15°C to 30°C. These SNR values were measured to result in particle detection efficiencies above 99.5% and 98% before and after irradiation, respectively. These satisfactory results allow to validate the TowerJazz0.18μm CMOS process for the ALICE ITS upgrade.

Spatiotemporal Dynamics of Early DNA Damage Response Proteins on Complex DNA Lesions

The response of cells to ionizing radiation-induced DNA double-strand breaks (DSB) is determined by the activation of multiple pathways aimed at repairing the injury and maintaining genomic integrity. Densely ionizing radiation induces complex damage consisting of different types of DNA lesions in close proximity that are difficult to repair and may promote carcinogenesis. Little is known about the dynamic behavior of repair proteins on complex lesions. In this study we use live-cell imaging for the spatio-temporal characterization of early protein interactions at damage sites of increasing complexity. Beamline microscopy was used to image living cells expressing fluorescently-tagged proteins during and immediately after charged particle irradiation to reveal protein accumulation at damaged sites in real time. Information on the mobility and binding rates of the recruited proteins was obtained from fluorescence recovery after photobleaching (FRAP). Recruitment of the DNA damage sensor protein NBS1 accelerates with increasing lesion density and saturates at very high damage levels. FRAP measurements revealed two different binding modalities of NBS1 to damage sites and a direct impact of lesion complexity on the binding. Faster recruitment with increasing lesion complexity was also observed for the mediator MDC1, but mobility was limited at very high damage densities due to nuclear-wide binding. We constructed a minimal computer model of the initial response to DSB based on known protein interactions only. By fitting all measured data using the same set of parameters, we can reproduce the experimentally characterized steps of the DNA damage response over a wide range of damage densities. The model suggests that the influence of increasing lesion density accelerating NBS1 recruitment is only dependent on the different binding modes of NBS1, directly to DSB and to the surrounding chromatin via MDC1. This elucidates an impact of damage clustering on repair without the need of invoking extra processing steps.

Quantum Tunneling Radiation of Charged Massive Particle from Reissner-Nordström-NUT Spacetime

By extending the semi-classical quantum tunneling method, the tunneling radiation of the massive charged particle from a charged Reissner-Nordstrom-NUT black hole was investigated. Difference from the uncharged mass-less particle, the geodesics of the charged massive particle tunneling from the black hole is not light-like, but determined by the phase velocity. The result shows that the tunneling rate depends on the emitted particle’s energy, NUT parameter and electric charge, and takes the same functional form as uncharged particle. It also proves that the exact emission spectrum is not strictly pure thermal, but is consistent with the underlying unitary theory.

CEA Charged Particle Irradiation Facilities for Nuclear Material Studies

CEA Charged Particle Irradiation Facilities for Nuclear Material Studies

Role of proton therapy in the treatment of cancer

Conventional radiation therapy directs photons (X-rays) and electrons at tumours with the intent of eradicating the neoplastic tissue while preserving adjacent normal tissue. Radiationinduced damage to healthy tissue and second malignancies are always a concern. Proton beam radiotherapy, one form of charged particle therapy, allows for excellent dose distributions, with the added benefit of no exit dose. These character istics make this form of radiotherapy an excellent choice for the treatment of tumours located next to critical structures. Although proton therapy is clearly capable of providing superior dose distributions as compared with photons, there are still some questions remain unanswered. Current evidence provides a limited indication for PBT. Actual clinical studies are needed to validate the virtual clinical data. This review focuses specifically on the clinical outcomes and adverse events with charged particle radiation therapy compared with other treatments in patients with cancer. Standart foton radyoterapisi ile cevre normal dokular korunur