heavy ions

..However, the biological effect of carbon-ion beams arising on normal neuron remains unknown. Therefore, this study was undertaken to investigate the effect of carbon-ion beams on neurons by using both morphological and functional assays...

..These results indicate that high-LET radiation has a significant and long-lasting effect on the neurogenic population in the hippocampus that involves cell loss and changes in the microenvironment...

..The RBE(max) for apoptosis 48 h after exposure was at least 3.4. In short, exposure to high-LET radiation results in a more efficient and greater induction of apoptosis in human neuronal progenitor cells than low-LET radiation...

..e. two independent hits are not required for cluster induction. Further, among all complex damages, double strand breaks comprise--at most-- ~20%, with the other clustered damages being at least 80%...

..Further, this review discusses some implications of radioprotection for the induction and/or propagation of genomic instability in the progeny of irradiated cells...

..From the results of this study, it can be concluded that carbon ion radiotherapy will deliver a high local control rate without unacceptable injuries to the surrounding normal tissues...

..The system allows efficient verification and documentation of carbon ion fields and is in principle also applicable to intensity-modulated photon beams...

..This delay was further emphasized in NHEJ-defective 180BR cells. Our results indicate that high-LET radiation induces complex DNA damage that is not easily repaired or is not repaired by NHEJ even at low radiation doses such as 2 Gy...

..To analyze the tolerance dose for retention of visual acuity in patients with head-and-neck tumors treated with carbon ion radiotherapy...

..Collectively, our results indicate that heavy ions inactivate clonogenic potential of bystander cells, and that the time course of the response to heavy ions ..

..between anhydrobiotic (dry) and non-anhydrobiotic (wet) samples after exposure to 1 - 7000 Gy of three types of heavy ions delivered from the azimuthally varying field (AVF) cyclotron with LET values ranging from 16.2 - 321 keV/microm...

..In spite of single ion irradiation, we frequently observed split fluorescence foci which might be explained by small-scale chromatin movements...

The deleterious processes triggered by heavy ions on DNA were studied through the determination of the yield of a series of oxidized bases...

..However, both values were within 15% of LET in all cases...

..missions, the Monte Carlo radiation transport code HETC is being extended to include transport of energetic heavy ions, such as are found in the galactic cosmic ray spectrum in space...

..Measurement without a target present gives an indication of the level of contamination of the primary beam, which is also important in radiobiology experiments...

..The relative frequencies of DSBs compared to abasic and oxybase clusters were higher for the charged particles-including the high-energy, low-LET protons-than for the ionizing photons...

..The data show that heterozygosity for the ATM gene predisposes the eye to the cataractogenic influence of heavy ions and suggest that ATM heterozygotes in the human population may also be radiosensitive...

..The residual activity and photon dose become larger with the increase in projectile energy per nucleon and the range of the projectile beam for the same projectile energy per nucleon...

..In contrast, e.g. for very heavy ions, there are significant discrepancies observed for the Katz approach...

Radiological protection against high-energy heavy ions has been an essential issue in the planning of long-term space missions...

..The health effects of exposure to high-LET radiation in humans on prolonged space flights should remain a matter of concern...

..The results suggest that different ion species may cause qualitative and quantitative difference in mutation induction even if the LET values are similar...

..The impact of heavy ions on sucrose produced sucrose radicals, which were measured by ESR...

..These results suggested that different biological endpoints may be suitable for different physical parameter, which represent the track structure of energy deposition of ion beams...

..The existence or otherwise of a beta component of the dose-response at these radiation qualities has important consequences for modelling mechanisms of aberration induction by radiation...

..dose heavy particle radiation to CNS system, we adopted mouse neonatal brain cells in culture being exposed to heavy ions generated by HIMAC at NIRS and BNL. The applied dose varied from 0.05 Gy up to 2.0 Gy...

..However, our data suggest a complex interaction between track structure and chromatin organization over several levels...

....

..0 and 1.45 and, for Z > 1, between 1.3 and 2. These relationships can be applied to derive information about the 'effective LET' in an unknown HCP field and to correct the TLD readings for dose evaluation...

..6 and 3 for early and delayed reproductive death, respectively. Analysis of the fluence-effect curves shows that the cross-sections for early and delayed inactivation increase with increasing LET up to 442 keV/micrometers...

..High quality accelerator-based research with heavy ions will continue to be the main source of knowledge of space radiation health effects and will lead to reductions ..

..for calculating total reaction cross sections, and addition of routines for calculating elastic scattering of heavy ions, and inclusion of radioactivity and burn up processes...

....

..These physical measurements will be used to characterize the beam used in parallel biological experiments...

....

..Protection is only observed at high iron ions energy, especially at 5 GeV/u, where PMMA shield gives higher protection compared to Al or Pb shields of the same thickness expressed in g/cm2...

..2 for tumor induction and 1.9 for early skin reaction. We conclude that risk of secondary tumor induction by carbon-ion radiotherapy would not be seriously higher than anticipated...

..The significance of this observation for the estimation of the health risk associated with space radiation remains to be elucidated...

..The "synergistic" effect of simultaneous charged particle transfers is accounted for by the "track overlap" mode inherent in the model of Katz...

..Presented are the test results of the prototype unit. The spherical phantom will be flown on the ISS in 2004 year and Liulin-5 experiment is planned for 2005 year...

The responses of a commercial diamond detector (type 60003, PTW-Freiburg) to several heavy ions were examined...

..It is still hard to appreciate the potential of 9C beams in cancer therapy based on the present LET spectrum measurement, but it provides a substantial basis for upcoming radiobiological experiments...

....

....

..Finally, the implication of these results for the dosimetry of heavy charged particles is discussed...

..As far as eta is concerned, the same tendencies were observed as for charged particles, i.e. when average LET of secondary particles formed in a TLD increases, their eta generally decreases...

..dose heavy particle radiation to CNS system, we adopted mouse neonatal brain cells in culture being exposed to heavy ions by HIMAC at NIRS and NSRL at BNL. The applied dose varied from 0.05 Gy up to 2.0 Gy...

..In addition, the EPR response had a linear relationship with dose in the dose range of 5-60 Gy. Thus the present EPR results show that sucrose can be used to monitor the ionizing particle based on the radical yield...

..These results suggested that quantitative and qualitative difference in mutation occurred when using different ion species even if similar LET values...

..Finally, applications of mutation detection systems for studies in space (section 3) are described, in which the carcinogenic effects of space environmental radiation are considered...

..Such a method for numerically assessing radiation quality may have implications for procedures for heavy ion protection in space at low doses and for understanding the initial mechanisms of radiation action...

..Stopping target yields and cross section measurements conducted at particle accelerators using heavy ions with energies > 100 MeV per nucleon are discussed.

..From this sparse information, pragmatic choices need to be made for application to protection in space. The data are reviewed and the bases for the pragmatic choices discussed...

..This comprises a series of seven work packages, which will be a focus for European collaboration...

..The detectors were calibrated using energetic heavy ions. Data obtained were compared with the predictions of the EPCARD and CARI-6 codes...

..We undertook the present study to clarify the RBE of therapeutic carbon ion radiation and molecular changes that occur in the rat mammary cancer model...

..The experiment consists in irradiating by fast ions cultured cells previously exposed to dichloroterpyridine Platinum (PtTC) and analyzing cell survival by a colony-forming assay...

In order to effectively utilize the prominent properties of heavy ions in radiotherapy, it is important to evaluate both the position of the field irradiated with incident ions and the absorbed dose distribution in a patient's body...

..and linear energy transfer (LET) in a potassium dithionate, K2S2O6 (PDT), dosimeter irradiated with the heavy ions C(6+) and N(7+)...

....

..We identify that difference as 'ion kill', associated with the spectrum of z/beta in the radiation field, whose measurement we label 'ion-kill dosimetry'...

..Data measured by means of a diamond detector and a spectrometer of linear energy transfer (LET) based on chemically etched track detectors are presented, analysed and discussed. LET spectra are also calculated by program SRIM...

..The preliminary results include energy- and angular distributions, fragment yields, build-up curves and attenuation of the primary carbon projectiles...

..Finally, the differences between our results and those obtained by another group using passive dosimeters on the MIR are discussed...

..of mixed high-/low-LET radiation fields, mammalian cells were exposed in vitro simultaneously to X-rays and heavy ions, accelerated at the HIMAC accelerator. X-ray doses ranged from 1 to 11 Gy...

..However, no proof of this effect has been provided by clinical trials and related clinical research. Hence, we investigated the radiation biological aspects of high LET carbon beam therapy on cervical cancer...

....

..Fast neutrons were detected using recoil protons produced in a polyethylene radiator installed in front of the crystalline detector. Three-dimensional reconstruction of a recoil proton propagating through the crystal was demonstrated...

..These are the first studies in which single-ion direct hit effect and the bystander effect have been investigated using a high-LET heavy particle microbeam...

..synchrotrons and linear accelerators, culminating in the BEVALAC, which provided the first source of very heavy ions (helium to argon) to be used clinically, beginning in 1975...

..It is also pointed out, however, that there may be unique effects from single tracks of heavy ions that do not occur from light-ion tracks. For such effects, the concepts of both RBE and RPPE lose their meaning.

..Accelerator generated high energy helium and heavy ions can produce skin cancer in rodents at high doses, but only if they penetrate deep into the dermis...

..Prior to initiation of clinical trials with protons, neutrons, pions, and heavy ions, it was generally believed that such particles might have a therapeutic advantage resulting from their greater ..

..B. subtilis spores were irradiated with X-rays and accelerated heavy ions (helium, carbon, silicon and iron) in the linear energy transfer (LET) range of 2-200 keV/mum...

..Few data on gene transcription activation by different heavy ions are available, suggesting a dependence on linear energy transfer...

..understanding of cancer risks from galactic cosmic rays (GCR), which are comprised of high-energy protons and heavy ions. The most comprehensive data set for tumor induction by heavy ions is the induction of Harderian gland tumors in ..

..In this study, we investigated tolerance of the tardigrade, Milnesium tardigradum, against gamma-rays and heavy ions by determining short-term or long-term survival, and reproductive ability after irradiation.

..This led to the evaluation of the oxygen enhancement ratio (OER) for photons (X-rays), neutrons and heavy ions. It was found that the OER for conventional radiation therapy (RT) with photons is much higher (about 3) than ..

..irradiations of different radiation types, such as gamma rays, neutrons and high linear energy transfer (LET) heavy ions. The cells were pretreated with low-dose (rate) or low-fluence irradiations (approximately 1 mGy/7-8 h) of 137Cs ..

Recently, heavy ions or ion beams have been used to generate new mutants or varieties, especially in higher plants...

Now many countries have developed cancer therapy with heavy ions, especially in GSI (Gesellschaft f r Schwerionenforschung mbH, Darmstadt, Germany), remarkable results have obtained, but due to the complexity of particle track structure, ..

..a given galactic cosmic ray (GCR) environment, information on the particle flux of protons, alpha particles, and heavy ions, that varies with respect to the topographical altitude on the Martian surface, are needed for planning ..

..002 V(-1) cm. The gradient of the line increases as the LET of the heavy ions increases. A strong LET dependence of the gradient was observed in air and carbon dioxide...

..IR), we investigated global gene expression in yeast irradiated by three types of high-LET IR (fast neutrons, heavy ions, and thermal neutrons) and gamma rays using DNA microarray analysis...

..high cost of launching these heavy structures into space and their inability to provide adequate shielding from heavy ions at a feasible shield thickness...

..cultured diploid bovine lens epithelial cells exposed to different LET irradiation to either 300 kV X-rays or to heavy ions at the UNILAC accelerator at GSI. Accelerated ions from Z=8 (O) to Z=92 (U) were used...

Medical X-ray computed tomography (CT) was applied to the measurement of the diffusion coefficients of heavy ions in an artificial barrier material for the disposal of nuclear wastes...

Space and cosmic radiation is characterized by energetic heavy ions of high linear energy transfer (LET)...

..Tracks of monoenergetic heavy ions and electrons were constructed by following the molecular interaction-by-interaction histories of the particles ..

..Complex chromosomal rearrangements do not represent a practical biomarker of radiation quality in our test subjects...

..is difficult in space due to the complexity of the space radiation environment, which consists of protons, heavy ions and secondary neutrons, and the modification of these radiation types in tissue as well as limitations in ..

To clarify the effect of heavy ions in plants, dry seeds of Arabidopsis were irradiated with carbon, neon, and argon ions with various linear energy transfer (LET) values...

..gel electrophoresis (PFGE) after the cells had been exposed on membrane filters to a variety of energetic heavy ions with values of linear energy transfer (LET) ranging from about 2 to 11,500 keV/microm, (241)Am alpha particles, ..

Jupiter's magnetotail is the largest cohesive structure in the solar system and marks the loss of vast numbers of heavy ions from the Jupiter system...

b>Heavy ions are more efficient in producing complex-type chromosome exchanges than sparsely ionizing radiation, and this can potentially be used as a biomarker of radiation quality...

..In the series of studies presented herein, the mutagenic effectiveness of high energy heavy ions is examined using human B-lymphoblastoid cells across an LET range from 32keV/micrometer to 190 keV/micrometer...

Astronauts receive exposures to high-energy heavy ions from galactic cosmic radiation...

..Accelerated heavy ions of helium and neon from the Berkeley Bevalac were used...

..Four experiments with heavy ions (Ar, C and U), as well as gamma-ray exposure, were conducted to enable comparisons...

..transport problem, and we point out how neutron production from protons is different than neutron production from heavy ions. We also make comparisons of one the heavy-ion data sets with Boltzmann-Uehling-Uhlenbeck (BUU) calculations.

..It is the secondary mutations that lead to advance, aggressive disease in people. ..

..It is expected that graduates of the training program will continue with their research and academic careers in radiation biology and oncology. ..

....

....

..In the future, we expect that the lower-risk treatments will result in fewer second cancers and this will translate into longer, higher-quality lives for survivors of childhood cancer (presently 270,000 persons in the United States). ..

..abstract_text> ..

..abstract_text> ..

..g., to enhance cell killing in tumor cells or prevent cell killing in AIDS, autoimmune diseases, neurodegenerative diseases, etc., where oxidative stress may play a role. ..

....

..abstract_text> ..

..abstract_text> ..

..abstract_text> ..

..Ultimately, the outcomes should establish a rationale for combining targeting of redox controlling proteins with other specific anti-cancer drugs to maximize apoptosis in cancer cells that are resistant to DNA damaging agents. ..

..The results will enhance our effort to establish clinically relevant radiation treatment with a better understanding of potential damage to healthy tissue. ..