Range Of Α-particles Research Articles

Evaluation of Toxicity and Tissue Radiation Doses Obtained in Mice with An Anti-CD45 Monoclonal Antibody (mAb) Labeled with the Alpha-Emitting Radionuclides, Astatine-211 or Bismuth-213.

Background: One strategy to decrease toxicity of conditioning regimens for hematopoietic cell transplantation (HCT) has been the use of radiation targeted systemically with radionuclide-labeled mAbs. While mAb labeled with β-emitting radionuclides have shown some efficacy, a more promising alternative is the use of α-particle emitters. In contrast to β-emitting radionuclides, the high linear energy transfer and short particle range of α-particles makes them particularly attractive for killing hematopoietic cells in the blood and marrow. We initially investigated bismuth-213 (213Bi)-labeled anti-CD45 mAb to replace total body irradiation (TBI) as nonmyeloablative conditioning for HCT. This conditioning successfully allowed sustained engraftment of allogeneic marrow in a canine model. However, the limited availability, very short t1/2 of 46 min, and cost to produce 213Bi place limitations in using this for clinical trials. Therefore, in this study we evaluated whether astatine-211 (211At), which has a longer half-life (t1/2 = 7.2 h) than 213Bi, gave comparable results when targeting hematopoietic cells in mice.Methods: After injecting with either 213Bi- or 211At-labeled rat anti-murine CD45 mAb 30F11, we evaluated myelosuppression and non-hematological toxicity with varying quantities of radioactivity (2, 10, 20, and 50 μCi) on 10 μg of 30F11 and 20 μCi of radioactivity on various quantities of 30F11 (2, 10 and 40 μg). We also evaluated biodistribution with 20 μCi on various quantities of 30F11.Results: In the biodistribution studies, the highest concentrations of radioactivity were seen in the spleen. The 211At concentrations ranged from 167–417 % injected dose/gram (% ID/g) at 24 h post injection while the 213Bi concentrations ranged from 45–166 % ID/g at 3 h post injection. This result suggested that the longer half-life of 211At might allow higher quantities of labeled mAb to reach the spleen before decay. Importantly, the longer half-life and higher spleen concentrations of 211At resulted in much higher radiation doses to that tissue (e.g. 29,450 cGy/50 mCi 211At administered vs. 1165 cGy/50 mCi 213Bi when 10 mg of mAb was employed). Significant cytopenias were not observed in any of the 213Bi groups. In contrast, lethal and irreversible myelosuppression was observed in the mice receiving 20 μCi 211At on 40 μg of 30F11 and 50 μCi 211At on 10 μg of 30F11 (minimal WBC counts 0.21 x 103 and 0.12 x 103/mm3, Plt counts 1.2 x 104 and 0.3 x 104/mm3, Hb levels 1.5 and 4.2 g/dl, respectively). In the mice receiving 20 μCi 211At on 10 μg of 30F11, significant but reversible pancytopenia was observed, with a nadir of 2 weeks after injection (minimal WBC count 0.45 x 103/mm3, Plt count 3.3 x 104/mm3, Hb level 9.9 g/dl). The pancytopenia resolved at 3 weeks after injection. The second highest concentrations both in 211At studies (18–50% ID/g) and 213Bi studies (19–33%ID/g) were observed in the liver. Reversible but severe acute hepatic toxicity (maximal AST 1329 IU/L and ALT 928 IU/L) occurred 3h after 50 μCi 213Bi but not after 50 μCi 211At injection. This was surprising given the fact that the estimated radiation dose given to liver after 50 mCi 213Bi injection was ~200 cGy whereas the liver dose ranged from 1350–2600 cGy for 50 mCi 211At (depending on the amount of labeled mAb). No significant renal toxicity was observed with either 211At or 213Bi labeled 30F11 during 8 weeks follow-up period.Conclusion: The study results suggest that we may be able to replace low dose TBI in nonmyeloablative conditioning regimens with much lower (mCi) quantities of 211At-labeled anti-CD45 mAb without major non-hematological toxicities compared to the same mAb labeled with 213Bi.

Radioanalytical determination of actinides and fission products in Belarus soils

Alpha emitting actinides such as plutonium, americium or curium were measured by α-spectrometry after radiochemical separation. The short range of α-particles within matter requires, after a pre-concentration process, a succession of isolation and purification steps based on the valence states modification of the researched elements. For counting, actinides were electrodeposited in view to obtain the mass-less source necessary to avoid self-absorption of the emitted radiations. Activity concentrations of gamma-emitting fission products were calculated after measurement with high purity germanium detectors (HPGe). These different methods were used to analyse soils sampled in the Republic of Belarus, not far from the Chernobyl nuclear plant.

Variation of alpha-particle track diameter in CR-39 as a function of residual energy and etching conditions

It has often been proposed that track diameter in etched detectors can be used for energy spectrometry. To test this proposition, the relationship between track diameter and energy of alpha particles, in the range 0.1–5.5 MeV, incident on CR-39 was studied. Two sets of detectors were irradiated by a collimated normally-incident beam of α-particles of different energies, using an Am-241 source. Different foils of the first set were etched for variable lengths of time in such a way that, in each case, the etchant reached the end of the latent track. Foils in the second set were etched for a fixed “short” time of 2 h, for all α-energies. The linear rate of energy loss as well as the residual range of α-particles was determined by using Henke and Benton’s computer program. It is found that, for “short” etching times, the track diameter mimics the “Bragg curve”, i.e., at first it rises with falling energy, and then declines, after the peak, at lower energies. If, however, the track is always etched to the end of the α-range, it is seen that the larger the α-energy the larger is the diameter. In other words, in all cases the integrated area under the Bragg curve, covering the etched portion, is a good indicator of the α-track diameter.

Gain of a compressed DT fuel statistically ignited by a multispark assembly

Most of the current inertial confinement fusion (ICF) schemes are based on the ignition of a high-density DT fuel by a single, high-temperature spherical hot spot (the spark). The spark is self-generated by the implosion process, which is used to bring the fuel to high density. To start ignition the spark has to be dimensioned in such a way that the ion temperature would be greater than 5–7 keV, and that the spark radius would be greater than the α-particle range. A spark with these features is indicated as supercritical. In the scheme based on self-generated spark, ignition can fail to occur when the produced spark strongly deviates from spherical shape, which can make all the surface losses highly relevant. High deformation, or even spark splitting, can occur due to the amplification of initial deviations from spherical shape by hydrodynamic instabilities (or by secular growth) during the implosion process. In principle, ignition can be recovered if the implosion is designed in such a way as to make supercritical at least one of the portions of hot fuel which are produced in this way near stagnation. As a general trend, more compressed final assemblies are required. In this paper we present fuel gain calculations (Gain = Thermonuclear energy/Energy in the compressed fuel) for DT assemblies ignited at the end of an implosion process by a supercritical spark statistically created within a cluster of many subcritical sparks. It is assigned the total number of sparks and the probability of having at least one of them supercritical. As a function of these quantities we calculate, in the framework of an isobaric model, the average thermal energy associated with the spark assembly. The same model is also used to evaluate, by statistical arguments, the areal mass, the burn fraction, and the system’s total fuel gain. It is found that the energy distribution function of the sparks is influenced only by a single global parameter, in which the assigned ignition probability and the number of sparks are also represented. Compared to the single central-spark approach, being the final states with allowed inner turbulence, the multispark scheme is characterized by relaxed initial symmetry requirements. For multispark systems we can realistically consider the achievement of fuel gains comparable or greater than those typical of the single-spark approach, when evaluated for currently accepted spark convergence ratios. With regard to the single spark case, higher cold fuel densities are needed, as expected (typically 2×–3×, for the same gain, depending on the energy distribution function).

The 11B(α, p) 14C reaction below 1.7 MeV bombarding energy

For estimation of the production rate of the long-lived 14C isotope originating in the controlled thermonuclear synthesis 11B + p the total cross section of the 11B(α, p) 14C reaction has been determined in the energy range of α-particles E α = 0.9−1.7 MeV. Five resonances corresponding to states in 15N have been observed. The assignment of the resonance parameters is discussed.

Dechanneling of alpha particles due to defects produced in NaCl crystal by thermal treatment

The range of α-particles (40 and 45 MeV) in crystals of NaCl heat-treated at various temperatures has been measured from the depth of F center coloration. The range has been found to be related to the temperature of firing.

Distributions of Cell Populations within α-Particle Range of Plutonium Deposits in the Rat and Beagle Testis

Plutonium is not uniformly distributed in testicular tissues; thus some cell populations may receive larger or smaller radiation exposures than would be expected if the nuclide were uniformly distributed. The distributions of cell populations within alpha-particle range of Pu deposits in rat and beagle testes were determined. The data were collected from autoradiographs of testicular tissues containing 241Pu. A cell distribution factor (CDF) was determined for each cell population and is defined as the average number of each cell type within alpha-particle range of each observed Pu deposit relative to the number of each cell type that would be expected within alpha-particle range of each Pu deposit, if the deposits were distributed uniformly. In addition, the percentage of the spermatogonial stem cell population within alpha-particle range of Pu deposits was determined. In rats, the CDF for the spermatogonial stem cells is about 2.2. This value is similar to other enhancement and inhomogeneity factors reported for rodents in the literature. In beagles the CDFs to all cells in the seminiferous epithelium were less than the rats. In addition, the percentage of spermatogonial cells within alpha-particle range of Pu concentrations in the interstitial tissues was a factor of about 3 less in the dog than in the rat. The largest CDFs seen in both species were in the interstitial tissues, particularly for Leydig cells. Because the organization of testicular tissues in the beagle is quite different from rodents but more similar to human, the results from this study suggest that extrapolations from rodents to humans may tend to overestimate the potential for radiation exposure to spermatogonial stem cells as well as the fraction of the spermatogonial stem cell population at risk to exposure from internally deposited 239Pu.

On neutron-induced and other noble gases in Allende inclusions

Noble gases have been measured in one bulk sample, six light inclusions, and one black xenolith from four specimens of the carbonaceous chondrite Allende which cover a range in their 60Co content of about a factor of ten. The release pattern obtained upon heating the samples at different temperature steps shows: 1. 1.) The parent nuclides of radiogenic 4He are finely dispersed throughout the inclusions in host minerals with grain sizes smaller than the typical range of α-particles within them; 2. 2.) Neon from the inclusions contains a component deficient in 20,21Ne which is most conspicuous at low temperatures. The apparent excess 22Ne ∗ is attributed to spallation reactions on sodium although the reasons for excluding NeE are weak; 3. 3.) 36 Ar/ 38 Ar ratios up to 90 are observed at release temperatures around 800°C. For inclusions from the same specimens the excess 36Ar ∗ is proportional to the chlorine content, for different specimens the chlorine-normalized amounts of 36Ar∗ tend to correlate with 60Co; 4. 4.) 80,82Kr are found enriched about 80 fold, the ratio of the excess amounts 80Kr ∗ 82Kr ∗ is 2.68 ± 0.06; 5. 5.) Xenon is dominated by 129Xe, the overabundances are accompanied by much smaller excesses of 128Xe. The ratio of the excess amounts 128Xe ∗ 129Xe ∗ is constant for inclusions from the same specimens while for different specimens there is a range of a factor of four. The abundance anomalies in Ar and Kr as well as that of 128Xe can be explained as being due to the capture of neutrons by Cl, Br, and I, respectively, during the exposure of the meteoroid to the cosmic radiation. There is no compelling evidence for a contribution from an early neutron irradiation nor, in the case of 36Ar, for a contribution from extinct 36Cl. The ratio of the specific excesses 36Ar ∗ 128Xe ∗ as well as the 80Kr ∗ 82Kr ∗ ratio indicate no more than ~20 percent of the neutrons to have been thermal neutrons.

Microdistribution of Thorotrast and dose to cellular structures

ThO 2 is known to be distributed quite inhomogeneously within the tissues of Thorotrast patients. For reasons of calculating the dose with special emphasis on tissue dose on cellular level in man, animal experiments were done, with regard to the agglomeration of ThO 2 particles as a function of time of Thorotrast burden and self-absorption of α-particles within Thorotrast aggregates of various sizes. Colloidal ThO 2, 25, 125, and 250 μl, was injected intravenously into female mice, or 2 ml of the colloid was administered intravascularly to male rabbits. The animals were sacrificed between 1 and 100, and 392 days, respectively, and tissue samples of the liver and spleen were analyzed by histoautoradiography and light and electron microscopy with respect to the aggregates' size distribution. For dose calculations the aggregates were assumed to be of spherical shape and classified into groups from 0.045 to 20 μm radius. Dose rate estimates were made with respect to cellular structures, cells adjacent to Thorotrast granules, and liver tissue in general, considering self-absorption of α-particles as a function of Thorotrast particle sizes and time of Thorotrast body burden. According to the results local dose rates may vary from about 4000 rad/year (cell membranes) to about 30 rad/year (mean dose rate to nuclei of liver cells), the mean dose rate to cells within the range of α-particles emitted from aggregates of some micrometers in diameter will be in the order of 0.2 mrad/year to 2 rad/year.

Detection Threshold for α-Particles on the Solid-State Track Detector of Celluloid Films

Experimental investigations have been made on track registration properties of α-particles in the solid-state track detector of celluloid film. Celluloid films exposed to α-particles of 4.4∼2.2 MeV were etched in NaOH(6N) solution at 40°C and 50°C. The upper limits of the critical (threshold) energy for track registration and the maximum registration range of α-particles in the detector have been found to be 3.7∼3.8 MeV and 19∼21 µm, respectively.

Annealing phenomena in reactor irradiated potassium chromate pellets in contact with boric acid pellets

The annealing of recoil 51Cr fragments in reactor irradiated potassium chromate pellets in contact with boric acid pellets has been examined. The retention increases as the width of the potassium chromate pellet increases up to a certain maximum which corresponds to 800 μ distance from the boric acid surface. The phenomenon is due to the release of α-particles from the B 10( n, α)Li 7 reaction in the boric acid pellet. Since the range of α-particles of the relevant energy is only a few μ, it is postulated that a secondary mechanism of energy transportation into the potassium chromate lattice is responsible for the annealing. Such a mechanism would be an exciton transfer.

Effect of nuclear surface diffuseness on diffraction scattering

A simple method is proposed for taking into account nuclear surface diffuseness in diffractional scattering. Theoretical predictions are compared with experimental data on the scattering of α-particles by Mg 24 nuclei. The range of α-particles in nuclear matter is estimated.

Mesh size effects in alpha-particle backscattering

Alpha-particle backscattering is a familiar technique for determining the elemental composition of surfaces. In the present work, the effect of the surface structure of the sample is investigated. It is found that the spectrum of the backscattered α particles depends on the surface structure; hence, the ability to resolve different nuclear species in the sample by this method depends on the nature of the surface. If the linear dimension of the surface structure is of the same order of magnitude as the α-particle range in the material, a significant change in the spectrum of backscattered α particles is observed. For surface structures much larger or much smaller than the α-particle range, normal spectrums are observed.

Determination of the range of α-particles by the decomposition of potassium iodide

Determination of the range of α-particles by the decomposition of potassium iodide

Measurement of the range of the α-particles of U I and U II with the “sphere method”

Summary The relation between the range of α-particles measured by the spheremethod and the extrapolated ionisation range is discussed. The ranges of U I and U II were measured by this method and found to be 27.47 and 33.0 mm in terms of air at 15° and 760 mm. These values agree, within the limits of accuracy, with the values found by Laurence and by Kurie. The conclusion is drawn that the Geiger-Nuttal-rule cannot be used to calculate the periods of transformation from the ranges with sufficient accuracy.

XXXVIII.The measurement of temperature of a coal-gas flame by “α-Particle Method”

Summary A flame of length 75 mm. is placed in the path of particles from polonium, so that the path lies partly in air and partly in the flame. With the help of an amplifier and an ionization chamber the position of the source is determined when the range of α-particles ends exactly on the entrance of the ionization chamber connected with the amplifier. The flame-path is then reduced to 25 mm., and the source moved till the range ends on the entrance of the chamber. The difference between these two positions of the source is found to be 43.06 ram., i. e., to decrease the flame-path by 50 mm. is equivalent to increase the air-path by (50—43.06) 6.94 mm.

On the range of α-particles in rare gases

In a recent paper R. H. Fowler (1) has calculated the atomic stopping powers of various substances for α-rays on the basis of Henderson’s (2) theory of the loss of energy of an α-ray in passing through matter, and has drawn attention to the desirability of a systematic investigation of the range of α-rays in different media. In particular, the considerable discrepancy between experiment and theory in the case of helium made it desirable to carry out further measurements with this gas for the purpose of confirmation. Also, it was considered that experiments on the range of α-rays in such comparatively simple substances as the rare gases would yield valuable information concerning the relation between the observed values of the stopping power and those calculated by Fowler. The simple monatomic gases have the great advantage, that we are free from the complications of molecular structure and dissociations. The range of the α-particles from polonium was investigated by E. P. Adams (3) for a number of gases by a scintillation method. For convenience, taking the value of the range in air at 15°C. and 760 mm. of mercury to be 3·93 cm., the corresponding values for argon and helium were 4·18 cm. and 13·58 cm. respectively. The ranges of the α-rays from polonium and radium C in helium were found by Taylor (4) to be 17·62 cm. and 32·54 cm. respectively. It will be seen that the results of Adams and Taylor for helium are very different. The preceding values for helium and argon seem to be the only data available in the case of the rare gases.

Range of α-Particles in Air at Different Temperatures

sRange of α-Particles in Air at Different TemperaturesA. F. KovarikA. F. KovarikSearch for more papers by this authorPublished Online:30 Jan 2014https://doi.org/10.1259/jrs.1914.0062SectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail About"Range of α-Particles in Air at Different Temperatures." Journal of the Röntgen Society, 10(41), p. 113 Previous article Next article FiguresReferencesRelatedDetails Volume 10, Issue 41October 1914Pages: 87-118 Copyright © 1914, the British Institute of Radiology History Published onlineJanuary 30,2014 Metrics Download PDF

Range ofα-Particles in Air at Different Temperatures

Range of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>α</mml:mi></mml:math>-Particles in Air at Different Temperatures