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PubMed2005

In vitro targeting of NG2 antigen by 213Bi-9.2.27 alpha-immunoconjugate induces cytotoxicity in human uveal melanoma cells.

PURPOSE: To examine uveal melanoma cell lines for the expression of human melanoma proteoglycan (NG2) using monoclonal antibody (mAb) 9.2.27 and subsequently to assess the in vitro specificity and cytotoxicity of mAb 9.2.27 conjugated to the alpha-particle-emitting radioisotope 213bismuth (213Bi-9.2.27) for uveal melanoma cells. METHODS: Immunocytochemistry and flow cytometry were used to examine OCM-1, OCM-3, OCM-8, OMM-1, Mel202 and 92-1 melanoma cell lines for NG2 expression. Melanoma cells were treated with test (213Bi-9.2.27) or control (213Bi-A2) alpha-immunoconjugates (AICs). The specific cytotoxicity of 213Bi-9.2.27 AIC was evaluated using an MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfenyl)-2H-tetrazolium, inner salt) assay. Cell death was also assessed using TUNEL. RESULTS: OCM-1, OCM-8, OMM-1, and Mel202 cells strongly expressed NG2. OCM-3 cells showed moderate expression and 92-1 cells were NG2-negative. 213Bi-9.2.27 specifically killed NG2-positive OCM-1, OCM-8, and OMM-1 cells in a concentration-dependent manner. D0 values for 37% cell survival of NG2-positive OCM-1, OCM-8, and OMM-1 cells were 5.8, 5.0, and 5.6 microCi, respectively, and the value was 43.4 muCi for NG2-negative 92-1 cells. CONCLUSIONS: The specific cytotoxicity of 213Bi-9.2.27 AIC for NG2-positive, but not NG2-negative, cells suggests NG2 is a suitable target for alpha-immunotherapy in uveal melanoma. 213Bi-9.2.27 AIC used directly or as adjunct therapy may be a promising new agent for treating NG2-positive uveal melanomas or metastases.

Antibodies, Bispecific↗

PubMed2005

234U/238U isotope ratios in groundwater from Southern Nevada: a comparison of alpha counting and magnetic sector ICP-MS.

The 234U/238U activity ratio (AR) is extensively used as a geochemical tool to investigate movement and flow relationships in major hydrological units, information that is particularly important when considering nuclear waste disposal. It is usually determined by radiochemical separation and concentration of U, followed by energy-specific alpha particle counting. Alternatively, sector field inductively coupled plasma mass spectrometry (SF-ICP-MS) can be used to measure U isotopic signatures directly in groundwater samples. Here, we compare the two methods for samples of spring and groundwater from southern Nevada. Results for samples stripped from stainless steel disks, previously used for alpha counting, and for splits of groundwater samples show good agreement between the methods. However, SF-ICP-MS is faster, requires much less sample, and produces essentially no waste. We demonstrate applicability of the SF-ICP-MS method for groundwater collected from over 25 wells on and near the Nevada Test Site during 2003. Uranium concentrations ranged from 0.17 to 9.87 ppb with a mean of 2.9 ppb, while 234U/238U AR values ranged from 1.9 to 11.5 with a mean of 4.3. Groundwater collected from deep wells in the northern part of the study area tended to have moderate to high U concentrations and AR values, possibly representative of older volcanic-type waters, whereas groundwater from wells in the Fortymile Wash area had relatively low AR and U concentrations, suggesting younger waters with a possible local recharge component.

Environmental Monitoring↗

PubMed2003

Background radiation: natural and man-made.

A brief overview and comparison is given of dose rates arising from natural background radiation and the fallout from atmospheric testing of nuclear weapons. Although there are considerable spatial variations in exposure to natural background radiation, it is useful to give estimates of worldwide average overall exposures from the various components of that background. Cosmic-ray secondaries of low linear energy transfer (LET), mainly muons and photons, deliver about 280 microSv a(-1). Cosmic-ray neutrons deliver about another 100 microSv a(-1). These low- and high-LET exposures are relatively uniform to the whole body. The effective dose rate from cosmogenic radionuclides is dominated by the contribution of 12 microSv a(-1) from 14C. This is due to relatively uniform irradiation of all organs and tissues from low-energy beta particles. Primordial radionuclides and their progeny (principally the 238U and 232Th series, and 40K) contribute about 480 microSv a(-1) of effective dose by external irradiation. This is relatively uniform photon irradiation of the whole body. Internally incorporated 40K contributes a further 165 microSv a(-1) of effective dose in adults, mainly from beta particles, but with a significant gamma component. Equivalent doses from 40K are somewhat higher in muscle than other soft tissues, but the distinction is less than a factor of three. Uranium and thorium series radionuclides give rise to an average effective dose rate of around 120 microSv a(-1). This includes a major alpha particle component, and exposures of radiosensitive tissues in lung, liver, kidney and the skeleton are recognised as important contributors to effective dose. Overall, these various sources give a worldwide average effective dose rate of about 1160 microSv a(-1). Exposure to 222Rn, 220Rn and their short-lived progeny has to be considered separately. This is very variable both within and between countries. For 222Rn and its progeny, a worldwide average effective dose rate is about 1105 microSv a(-1). For 220Rn and its progeny, the corresponding value is 91 microSv a(-1). In both cases, the effective dose is mainly due to a particle irradiation of the bronchial tissues of the lungs. Overall, the worldwide average effective dose rate from natural background is about 2400 microSv a(-1) or 2.4 mSv a(-1). For comparison, worldwide average effective dose rates from weapons fallout peaked at 113 microSv a(-1) (about 5% of natural background) in 1963 and have since fallen to about 5.5 microSv a(-1) (about 0.2% of natural background). These values perhaps serve to emphasise that even gross insults to the natural environment from anthropogenic releases of radioactive materials are likely to be of limited significance when set in the context of the ambient radioactive environment within which all organisms, including humans, have developed.

Animals↗

PubMed2007

Bayesian reconstruction of nanodosimetric cluster distributions at 100% detection efficiency.

Ionisation spectra in nanometric volumes at a given distance from a charged particle track are obtained by using electron (or ion) gas detectors, having non-uniformly distributed detection efficiency. Therefore, such spectra should be properly processed in order to reconstruct the frequency distribution of clusters really produced in the detector gas. A Bayesian unfolding has been applied to ionisation distributions due to 5.4 MeV alpha particles in a 20-nm site obtained by Monte Carlo simulations, taking into account different detection efficiency conditions. It will be shown that Bayesian analysis provides a valid tool for reconstructing the true ionisation distributions, well beyond the maximum measured cluster size.

Bayes Theorem↗

PubMed1994

Evidence against the "oxygen-in-the-track" hypothesis as an explanation for the radiobiological low oxygen enhancement ratio at high linear energy transfer radiation.

Oxygen sensitizes cells toward the effect of ionizing radiation. This sensitization, quantified by the oxygen enhancement ratio (OER), decreases with increasing ionization density or linear energy transfer (LET) of the radiation applied. One explanation for the decreased OER at high LET offers the "oxygen-in-the-track" hypothesis. It claims that oxygen is produced in the track of densely ionizing particles providing an oxic microenvironment around the relevant cellular target molecules, even if cells are exposed under anoxic atmospheric conditions. Experimental evidence is presented against this hypothesis. It is based on the different kinetic pattern of DNA double-strand-break rejoining observed in yeast cells exposed under oxic or anoxic conditions to 3.5 MeV alpha-particles.

DNA↗

PubMed1984

The monitoring and prediction of solar particle events--an experience report.

The routine monitoring and prediction of solar proton events that may be a hazard to personnel and materials in space are a routine service of the Space Environment Services Center in Boulder, Colorado, U.S.A. The services provided are made available to the space centers in the United States for use in their operations. The real time monitoring consists primarily of Space Environment Monitors on both geosynchronous and polar orbiting weather satellites. The monitoring emphasizes proton fluxes but alpha particles, electrons, and in one case, heavier particles, are included. The predictions are of two types; a general outlook made 1 to 3 days in advance, and specific prediction of event size and probability of occurrence made after a solar flare occurs. The accuracy of the prediction made for solar cycle 21 are assessed.

Earth, Planet↗

PubMed2001

The use of silicon photodiodes for radon and progeny measurements.

Reduced cost, high quantum efficiency and very good detection characteristics of PIN silicon photodiodes made possible their utilization for alpha particles detection. This paper presents different studies and applications of this type of detector for qualification and quantification of radon and its progeny in laboratory and in the field. Since photodiodes are sensitive to environmental electromagnetic fields, protecting cells were adapted for use around the detector. A small three-channel (2-5.5 MeV; 5.5-6.5 MeV; 6.5-8.2 MeV) portable alpha counter was developed that allows the determination of the radon concentration and the radon exhalation rate. Numerous field applications were conducted in different conditions (uranium waste storage, dwellings, etc.) where this simple and inexpensive instrumentation demonstrated very good performance, reliability, and easiness of operation while measuring radon concentrations from 50-100 Bq m(-3) to several MBq m(-3).

Equipment Design↗

PubMed1997

A new device to measure the activity size distribution of radon progeny in a low level environment.

In order to easily measure the activity size distribution of radon progeny, a new instrument was developed that can determine their activity median diameter in a low level environment within 90 min. A four stage low-pressure cascade impactor was used. The particle size cut-off points were >2,100, 700, 210 and 70 nm, based on a particle density of 1 g cm(-3). A 300 metal wire screen diffusion collector facing with a silicon semiconductor detector was placed within the first air inlet in order to measure unattached radon progeny concentrations and also to prevent unattached progeny from entering the impactor. Silicon photodiodes, from which the ceramic windows were removed, were installed in each stage of the impactor. Alpha particles could be effectively detected with 46.2% efficiency as radon progeny were directly collected on the detecting surface of the photodiode. The surface of the photodiodes was coated with silicon grease to prevent particle bounce-off. An inline-type filter holder with a silicon semiconductor detector was connected at the exit of the impactor in order to collect the remaining radon progeny and to measure their concentrations. The instrument was used to concurrently measure the size distribution of radon progeny and the aerosol in the natural environment. The results indicated that the activity median diameter fell in between the median diameter of the aerosol derived from number statistics and that derived from surface-area statistics. A negative correlation was found between the unattached fraction (f(p)) and the activity median diameter.

Aerosols↗

PubMed2002

Ionisation clusters at DNA level: experimental modelling.

The importance of initial clustered damage to DNA is a hypothesis, which has to be approached also from physical modelling of the initial products of single charged particle interaction with DNA. A new tool for such studies, presented here, is based on modelling of the ionisation patterns resulting from a single charged particle crossing a nitrogen cavity of nanometre size. The nanometre size sites equivalent in unit density to DNA and nucleosome, have been modelled in a device, called a Jet Counter, consisting of a pulse operated valve which injects nitrogen in the form of an expansion jet into an interaction chamber. The distributions of the number of ions in a cluster created by a single alpha particle of 4.6 MeV along 0.15 nm to 13 nm size in nitrogen have been measured. A new descriptor of radiation action at DNA level is proposed.

DNA↗

PubMed2001

Boronated dipeptide borotrimethylglycylphenylalanine as a potential boron carrier in boron neutron capture therapy for malignant brain tumors.

Takagaki, M., Ono, K., Masunaga, S-I., Kinashi, Y., Oda, Y., Miyatake, S-I., Hashimoto, N., Powell, W., Sood, A. and Spielvogel, B. F. Boronated Dipeptide Borotrimethylglycylphenylalanine as a Potential Boron Carrier in Boron Neutron Capture Therapy for Malignant Brain Tumors. Radiat. Res. 156, 118-122 (2001).A boronated dipeptide, borotrimethylglycylphenylalanine (BGPA), was synthesized as a possible boron carrier for boron neutron capture therapy (BNCT) for malignant brain tumors. In vitro, at equal concentrations of (10)B in the extracellular medium, BGPA had the same effect in BNCT as p-boronophenylalanine (BPA). Boron analysis was carried out using prompt gamma-ray spectrometry and track-etch autoradiography. The tumor:blood and tumor:normal brain (10)B concentration ratios were 8.9 +/- 2.1 and 3.0 +/- 1.2, respectively, in rats bearing intracranial C6 gliosarcomas using alpha-particle track autoradiography. The IC(50), i.e. the dose capable of inhibiting the growth of C6 gliosarcoma cells by 50% after 3 days of incubation, was 5.9 x 10(-3) M BGPA, which is similar to that of 6.4 x 10(-3) M for BPA. The amide bond of BGPA is free from enzymatic attack, since it is protected from hydrolysis by the presence of a boron atom at the alpha-carbon position of glycine. These results suggest promise for the use of this agent for BNCT of malignant brain tumors. Further preclinical studies of BGPA are warranted, since BGPA has advantages over both BPA and BSH.

Alanine↗

PubMed2005

Fast decision in favor of the slow fission process.

The fission probability P(f) of highly excited targetlike nuclei produced in reactions of 2.5 GeV protons on Au, Bi, and U was studied as a function of excitation energy E* whereby E* is deduced eventwise from the multiplicity of evaporated light particles. At the highest E* of 1000 MeV P(f) amounts to approximately 30% with all 3 target nuclei irrespective of the initial fissility. Statistical-model calculations satisfactorily reproduce the observed evolution of P(f) with E*--provided that no extra transient delay is introduced. Fission thus is decided upon very fast and early in the long deexcitation chain towards scission which comprises as much as approximately 80% of all evaporated alpha particles.

Journal Article↗

PubMed2006

Dosimetric characterization of radionuclides for systemic tumor therapy: influence of particle range, photon emission, and subcellular distribution.

Various radionuclides have been proposed for systemic tumor therapy. However, in most dosimetric analysis of proposed radionuclides the charged particles are taken into consideration while the potential photons are ignored. The photons will cause undesirable irradiation of normal tissue, and increase the probability of toxicity in, e.g., the bone marrow. The aim of this study was to investigate the dosimetric properties according to particle range, photon emission, and subcellular radionuclide distribution, of a selection of radionuclides used or proposed for radionuclide therapy, and to investigate the possibility of dividing radionuclides into groups according to their dosimetric properties. The absorbed dose rate to the tumors divided by the absorbed dose rate to the normal tissue (TND) was estimated for different tumor sizes in a mathematical model of the human body. The body was simulated as a 70-kg ellipsoid and the tumors as spheres of different sizes (1 ng-100 g). The radionuclides were either assumed to be uniformly distributed throughout the entire tumor and normal tissue, or located in the nucleus or the cytoplasm of the tumor cells and on the cell membrane of the normal cells. Fifty-nine radionuclides were studied together with monoenergetic electrons, positrons, and alpha particles. The tumor and normal tissue were assumed to be of water density. The activity concentration ratio between the tumor and normal tissue was assumed to be 25. The radionuclides emitting low-energy electrons combined with a low photon contribution, and the alpha emitters showed high TND values for most tumor sizes. Electrons with higher energy gave reduced TND values for small tumors, while a higher photon contribution reduced the TND values for large tumors. Radionuclides with high photon contributions showed low TND value for all tumor sizes studied. The radionuclides studied could be divided into four main groups according to their TND values: beta emitters, Auger electron emitters, photon emitters, and alpha emitters. The TND values of the beta emitters were not affected by the subcellular distribution of the radionuclide. The TND values of the Auger electron emitters were affected by the subcellular radionuclide distribution. The photon emitters showed low TND values that were only slightly affected by the subcellular radionuclide distribution. The alpha emitters showed high TND values that were only slightly affected by the subcellular radionuclide distribution. This dosimetric characterization of radionuclides may be valuable in choosing the appropriate radionuclides for specific therapeutic applications.

Body Burden↗

PubMed2003

Ion-counting nanodosimetry: current status and future applications.

There is a growing interest in the study of interactions of ionizing radiation with condensed matter at the nanometer level. The motivation for this research is the hypothesis that the number of ionizations occurring within short segments of DNA-size subvolumes is a major factor determining the biological effectiveness of ionizing radiation. A novel dosimetry technique, called nanodosimetry, measures the spatial distribution of individual ionizations in an irradiated low-pressure gas model of DNA. The measurement of nanodosimetric event size spectra may enable improved characterization of radiation quality, with applications in proton and charged-particle therapy, radiation protection, and space research. We describe an ion-counting nanodosimeter developed for measuring radiation-induced ionization clusters in small, wall-less low-pressure gas volumes, simulating short DNA segments. It measures individual radiation-induced ions, deposited in 1 Torr propane within a tissue-equivalent cylindrical volume of 2-4 nm diameter and up to 100 nm length. We present first ionization cluster size distributions obtained with 13.6 MeV protons, 4.25 MeV alpha particles and 24.8 MeV carbon nuclei in propane; they correspond to a wide LET range of 4-500 keV/microm. We are currently developing plasmid-based assays to characterize the local clustering of DNA damage with biological methods. First results demonstrate that there is increasing complexity of DNA damage with increasing LET. Systematic comparison of biological and nanodosimetric data will help us to validate biophysical models predicting radiation quality based on nanodosimetric spectra. Possible applications for charged particle radiation therapy planning are discussed.

DNA↗

PubMed1998

The development of a [211AT]-astatinated endoradiotherapeutic drug: part IV--late radiation effects.

PURPOSE: 6-[211At]-astato-MNDP is a high-LET endoradiotherapeutic drug that selectively targets to an oncogenically associated alkaline phosphatase isoenzyme expressed by certain tumors. A detailed histopathological study of the late tissue effects of its endogenous alpha-particle emissions has been carried out in a murine tumor model. MATERIALS AND METHODS: Thyroid-blocked male C57BI/10 mice bearing a s.c. transplanted rectal adenocarcinoma were treated with a single i.p. injection of 10-750 kBq 6-[211At]-astato-MNDP. Cured mice (131) were studied. Detailed autopsies and histological examinations were performed on all mice. The study was concluded after 756 days. RESULTS: Lymphoma, plasmacytoma, and intercurrent infections secondary to chronic pulmonary fibrosis were the most commonly found late manifestations of alpha-radiation exposure. Low grade B-cell non-Hodgkin's lymphoma occurred in 19 (24.7%) of 77 mice, 13-17 months after receiving 3.5-185 kBq 6-[211At]-astato-MNDP. The incidence of lymphoma alone and its latency was similar to that of the control population (23.3%). Treatment doses exceeding 200 kBq 6-[211At]-astato-MNDP, were associated with the development of soft tissue plasmacytoma in 7 (13%) of 54 mice, after 17-22 months. Generalized debilitation and nonspecific infections supervening pulmonary fibrosis significantly contributed to the late morbidity and mortality observed in mice treated with 300-750 kBq 6-[211At]-astato-MNDP. Dosimetry has afforded LD50/360 and LD50/420 estimates of 12-14 and 10-12 Cobalt-Gray equivalent (CGyE), respectively, for chronic lung damage. There was no histological evidence of chronic radiation damage to other critical healthy tissues. Normal thyroid morphology was preserved. CONCLUSIONS: Dose activities of 6-[211At]-astato-MNDP exceeding 300 kBq, were associated an increased risk of tumor induction and development of varying degrees of chronic pulmonary fibrosis implicated in the onset of terminal intercurrent infections. Within the therapeutic dose range 55-300 kBq 6-[211At]-astato-MNDP, mortality associated with the incidence of significant late radiation damage in critical normal tissues and latent carcinogenesis was less than 15%. Data from this murine model suggest that clinically relevant activities of 6-[211At]-astato-MNDP may be given without unacceptable toxicity.

Animals↗

PubMed2002

Reactive oxygen species in cell responses to toxic agents.

This review first summarizes experimental data on biological effects of different concentrations of ROS in mammalian cells and on their potential role in modifying cell responses to toxic agents. It then attempts to link the role of steadily produced metabolic ROS at various concentrations in mammalian cells to that of environmentally derived ROS bursts from exposure to ionizing radiation. The ROS from both sources are known to both cause biological damage and change cellular signaling, depending on their concentration at a given time. At low concentrations signaling effects of ROS appear to protect cellular survival and dominate over damage, and the reverse occurs at high ROS concentrations. Background radiation generates suprabasal ROS bursts along charged particle tracks several times a year in each nanogram of tissue, i.e., average mass of a mammalian cell. For instance, a burst of about 200 ROS occurs within less than a microsecond from low-LET irradiation such as X-rays along the track of a Compton electron (about 6 keV, ranging about 1 microm). One such track per nanogram tissue gives about 1 mGy to this mass. The number of instantaneous ROS per burst along the track of a 4-meV alpha-particle in 1 ng tissue reaches some 70000. The sizes, types and sites of these bursts, and the time intervals between them directly in and around cells appear essential for understanding low-dose and low dose-rate effects on top of effects from endogenous ROS. At background and low-dose radiation exposure, a major role of ROS bursts along particle tracks focuses on ROS-induced apoptosis of damage-carrying cells, and also on prevention and removal of DNA damage from endogenous sources by way of temporarily protective, i.e., adaptive, cellular responses. A conclusion is to consider low-dose radiation exposure as a provider of physiological mechanisms for tissue homoeostasis.

Antioxidants↗

PubMed2004

Targeting of HER2 antigen for the treatment of disseminated peritoneal disease.

The studies reported herein demonstrate the efficacy of alpha-particle-targeted radiation therapy of peritoneal disease with Herceptin as the targeting vehicle. Using the CHX-A-DTPA linker, Herceptin was radiolabeled with indium-111 and bismuth-213 with high efficiency without compromising immunoreactivity. A pilot radioimmunotherapy study treating mice bearing 5-day LS-174T (i.p.) xenografts, a low but uniform HER2 expressing, human colon carcinoma, with a single dose of (213)Bi-CHX-A"-Herceptin, proved disappointing. This defined the effect of tumor burden/size on tumor response to radioimmunotherapy with alpha-radiation. A more successful experiment with a lower tumor burden (3 days) in mice followed. A specific dose-response (P = 0.009) was observed, and although a maximum-tolerated dose was not determined, a dose of 500 to 750 muCi was selected as the operating dose for future experiments based on changes in animal weight. Median survival was increased from 20.5 days for the mock-treated mice to 43 and 59 days with 500 and 750 muCi, respectively. The therapeutic effectiveness of (213)Bi-CHX-A"-Herceptin was also evaluated in a second animal model for peritoneal disease with a human pancreatic carcinoma (Shaw). The results of this study were not as dramatic as with the former model, and higher doses were required to obtain an increase in survival of the mice (P = 0.001).

Animals↗

PubMed2006

Determination of (234)U/ (238)U isotope ratios in environmental waters by quadrupole ICP-MS after U stripping from alpha-spectrometry counting sources.

The 234U/238U isotope ratio has been widely used as a tracer for geochemical processes in underground aquifers. Quadrupole-based inductively coupled plasma mass spectrometry (ICP-MS) equipped with a high-efficiency nebulizer and a membrane desolvator was employed for the determination of 234U/238U isotope ratios in natural water samples. The instrumental limit of detection for 234U was at the low pg L(-1) level with very low sample consumption. Measurement precision (234U/238U) was 3-5% for bottled mineral water with elevated uranium concentration (>1 microg L(-1)). For the analysis of groundwater samples from the Almonte-Marisma underground aquifer (Huelva, Spain), uranium was stripped from stainless steel planchets that had previously been used as radiometric counting sources for alpha-particle spectrometry. Potential spectral interferences from other metals introduced during the dissolution were investigated. Matrix-matched blank solutions were needed to subtract the background on 234U due to the formation of platinum argides, and to allow for mass bias correction and background correction. The Pt appears to be an impurity present in the stainless steel, either as a minor component by itself or after extraction from the anode and a subsequent uranium electrodeposition. The 234U/238U isotope ratio data were in very good agreement with those of alpha spectrometry, while precision was improved by a factor of up to 10 and counting time was reduced down to approximately 20 min (10 replicate measurements).

Journal Article↗

PubMed2006

Monte Carlo simulation of water radiolysis for low-energy charged particles.

The paper describes the development of chemical modules simulating the prechemical and chemical stages of charged particle tracks in pure liquid water. These calculations are based on our physical track structure codes for electrons and ions (KURBUC, LEPHIST and LEAHIST) which provide the initial spatial distribution of H2O+, H2O* and subexcitation electrons at approximately 10(-15) s. We considered 11 species and 26 chemical reactions. A step-by-step Monte Carlo approach was adopted for the chemical stage between 10(-12) s and 10(-6) s. The chemistry codes enabled to simulate the non-homogeneous chemistry that pertains to electron, proton and alpha-particle tracks of various linear energy transfers (LET). Time-dependent yields of chemical species produced by electrons and ions of different energies were calculated. The calculated primary yields (G values at 10(-6) s) of 2.80 for OH and 2.59 for e(aq)- for 1 MeV electrons are in good agreement with the published values. The calculated G values at 10(-6) s for a wide range LETs from of 0.2 to 235 keV microm(-1) were obtained. The calculations show the LET dependence for OH and H2O2. The electron penetration ranges were calculated in order to discuss the role of low energy electrons.

Computer Simulation↗