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- Biological dose (1)
- Dose distribution (1)
- Heavy ion (1)
- Heavy ion therapy (1)
- Heavy ion track (1)
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- Ion-kill (1)
- Katz Model (1)
- Late effects (1)
- Lithium fluoride (1)
- Particle track (1)
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- Tracks; radiobiology; dosimetry; fractionation; radiation therapy (1)
Articles 31 - 60 of 191
Full-Text Articles in Physical Sciences and Mathematics
Experimental And Theoretical Cross Sections For Escherichia Coli Mutants B, B/R, And BS-1 After Heavy-Ion Irradiation, Robert Katz, Rashidah Zachariah
Experimental And Theoretical Cross Sections For Escherichia Coli Mutants B, B/R, And BS-1 After Heavy-Ion Irradiation, Robert Katz, Rashidah Zachariah
Robert Katz Publications
Data for the inactivation of three Escherichia coli mutants by energetic heavy ions are fitted by the track theory of a one-hit detector in an extended target mode. The respective E0’s are 46, 36.5, and 12.6 Gy for E. coli B, B/r, and Bs-1, and a0, the assumed target radius, is 0.5 μm for all three. The parameter E0, the D37 with γ rays, is measured directly, while a0 is fitted to the data. It is significant that neither a point target model nor calculations with a0= 0.2 …
Relative Effectiveness Of Mixed Radiation Fields, Robert Katz
Relative Effectiveness Of Mixed Radiation Fields, Robert Katz
Robert Katz Publications
For all one-hit detectors the relative effectiveness of a mixed radiation field may be found as the dose-weighted average of the relative effectiveness of its components, segregated according to the atomic number Z and the energy T. We emphasize that this procedure is incorrect for mammalian cells, whatever the nature of the segregation.
A Track Physics Retrospective, Robert Katz
A Track Physics Retrospective, Robert Katz
Robert Katz Publications
Many condensed matter dosimeters and detectors respond to the perspectives of track physics, a parametric model which relates their response to gamma rays to their response to heavy ions through the radial distribution of dose about a heavy ion’s path. Most dosimeters are treated as 1-hit detectors, a classification which includes emulsions, scintillators, TLDs, the Fricke dosimeter, alanine, and some biological substances: enzymes and Eschericia coli, among others. We have discovered many hit detectors. An extended model describes the killing, transformation, and mutation of biological cells after gamma and heavy ion irradiation. A detector is treated as a black box, …
A Model Of Cell Damage In Space Flight, Robert Katz, F. A. Cucinotta, J. W. Wilson, J. L. Shinn, Duc M. Ngo
A Model Of Cell Damage In Space Flight, Robert Katz, F. A. Cucinotta, J. W. Wilson, J. L. Shinn, Duc M. Ngo
Robert Katz Publications
Cell damage by high LET radiations has been described by a phenomenological model (track theory) for 20 years and more. Molecules of biological significance (dry enzymes and viruses) act as 1 hit detectors. Recent additions to the class of I-hit detectors are E. Coli B, and the creation of both single and double strand breaks in SV-40 virus in EO buffer, where indirect effects predominate. The response of cells (survival, transformation, chromosome aberration) to these radiations is typically described by a 4-parameter model whose numerical values are determined by fitting the equations of the theory to experimental data at high …
Katz Model Prediction Of Caenorhabditis Elegans Mutagenesis On Sts-42, Francis A. Cucinotta, John W. Wilson, Robert Katz, Gautam Badhwar
Katz Model Prediction Of Caenorhabditis Elegans Mutagenesis On Sts-42, Francis A. Cucinotta, John W. Wilson, Robert Katz, Gautam Badhwar
Robert Katz Publications
The Katz track structure model has been applied to describe recessive lethal mutagenesis in the nematode Caenorhabditis elegans after exposure to heavy ions. Based on models of the cosmic-ray environment and heavy-ion transport, mutation rates for the International Microgravity Laboratory 1 (IML-1) experiment on the Space Transportation System 42 (STS-42) are predicted and the results are discussed.
Track Structure Model Of Cell Damage In Space Flight, Robert Katz, Francis A. Cucinotta, John W. Wilson, Judy L. Shinn, Duc M. Ngo
Track Structure Model Of Cell Damage In Space Flight, Robert Katz, Francis A. Cucinotta, John W. Wilson, Judy L. Shinn, Duc M. Ngo
Robert Katz Publications
Cell damage by high linear energy transfer (LET) radiations has been described by a phenomenological model (track theory) for more than 20 years. With track theory, molecules of biological significance (dry enzymes and viruses) act as one-hit detectors. Recent additions to tire class of one-hit detectors arc Escherichia coil B, and single- and double-strand breaks in SV-40 virus in EO buffer, where indirect effects predominate. The response of cells (survival, transformation, and chromosome aberration) to these radiations is typically described by a four-parameter model whose numerical values are determined from the equations of the theory being fit to experimental …
Track Structure Model For Damage To Mammalian Cell Cultures During Solar Proton Events, Francis A. Cucinotta, J. W. Wilson, L. W. Townsend, J. L. Shinn, Robert Katz
Track Structure Model For Damage To Mammalian Cell Cultures During Solar Proton Events, Francis A. Cucinotta, J. W. Wilson, L. W. Townsend, J. L. Shinn, Robert Katz
Robert Katz Publications
Solar proton events (SPEs) occur infrequently and unpredictably, thus representing a potential hazard to interplanetary space missions. Biological damage from SPEs will be produced principally through secondary electron production in tissue, including important contributions due to delta rays from nuclear reaction products. We review methods for estimating the biological effectiveness of SPEs using a high energy proton model and the parametric cellular track model. Results of the model are presented for several of the historically largest flares using typical levels and body shielding.
Comment On Ncrp Report No. 104, "The Relative Biological Effectiveness Of Radiations Of Different Quality", Robert Katz
Comment On Ncrp Report No. 104, "The Relative Biological Effectiveness Of Radiations Of Different Quality", Robert Katz
Robert Katz Publications
The validity of a linear extrapolation to lowest fluences of charged particles demands that the transit of a single charged particle through the target volume is capable of inducing the chain of events leading to an observable end-point. This is always the case for one-hit detectors. It is not always the case for biological cells and tissues (Katz and Hofmann 1982).
By way of example, Cole ct al. (1980) found that, on average, some 500 electrons pass into the nucleus of a CHO cell for inactivation. Similarly, Warters et al. (1977) found that some 500 tritium decays in the nucleus …
Track Physics Model Of Radiation Effects, Robert Katz
Track Physics Model Of Radiation Effects, Robert Katz
Robert Katz Publications
Radiation effects induced by heavy ions in many materials with diverse end points are well described by the conceptual structure and equations of track physics, first developed for heavy ion tracks in nuclear emulsions. The model describes scintillators, biological cell inactivation and mutation, radiation chemistry, latent tracks in insulators, the response of resists to heavy ions, and other systems. A detector is taken to be composed of small targets whose response to ionizing radiation is principally to secondary electrons. The response is calibrated through determination of the probability of target (in)activation as a function of the absorbed dose of γ …
A Track Physics Model Of Radiation Action, Robert Katz
A Track Physics Model Of Radiation Action, Robert Katz
Robert Katz Publications
A model of radiation action by energetic heavy ions, inspired by a study of particle tracks in electron sensitive emulsion, has been successfully applied to many radiation effects in condensed matter, yielding quantitative descriptions and occasional predictions. Radiation effects are attributed primarily to secondary electrons. Each detector is imagined to be a collection of targets whose radiosensitivity is represented parametrically. We avoid a mechanistic description of detector response so as to retain the global character of the model. Attention is focused on the structure of particle tracks, on the radial deposition of dose about an ion’s path by “δ-rays,” and …
Rbe Vs. Dose For Low Doses Of High-Let Radiations, Robert Katz, F. A. Cucinotta
Rbe Vs. Dose For Low Doses Of High-Let Radiations, Robert Katz, F. A. Cucinotta
Robert Katz Publications
(LET) radiations varies with cellular radiosensitivity parameters and the radiation environment. Of special interest is that the RBE varies as the dose of high-LET radiation to the power (1/m - 1) where /m is the “target number” parameter, which varies from 2-4 in different cell lines. This applies to neutrons as well as to heavy ions at sufficiently low doses such that cells are not activated in the γ-kill mode; that is, the tracks of single heavy ions are sufficiently far apart so that there are few cases of inter-track inactivation.
Comment On “Microdosimetry And Katz’S Track Structure Theory” By Marco Zaider, Robert Katz
Comment On “Microdosimetry And Katz’S Track Structure Theory” By Marco Zaider, Robert Katz
Robert Katz Publications
To test radiobiological models one needs data from X- or γ-ray and HZE track segment irradiations of the widest possible dynamic range in dose, LET, end points, and test objects (enzymes, viruses, bacteria, cells, tissues, organs, and organisms). Some data are currently available. There are excellent data on the inactivation of dry enzymes and viruses which should serve as a test of every biophysical model. On many occasions Zaider has asserted the superiority of microdosimetric over track structure models, asserting that “radial dose distributions (on which track structure theory is based) are generally poor substitutes for exact microdosimetric distributions.” I …
Biological Effectiveness Of High-Energy Protons: Target Fragmentation, Francis A. Cucinotta, Robert Katz, John W. Wilson, Lawrence W. Townsend, Judy Shinn, Ferenc Hajnal
Biological Effectiveness Of High-Energy Protons: Target Fragmentation, Francis A. Cucinotta, Robert Katz, John W. Wilson, Lawrence W. Townsend, Judy Shinn, Ferenc Hajnal
Robert Katz Publications
High-energy protons traversing tissue produce local sources of high-linear-energy-transfer (LET) ions through nuclear fragmentation. We examine the contribution of these target fragments to the biological effectiveness of high-energy protons using the cellular track model. The effects of secondary ions are treated in terms of the production collision density using energy-dependent parameters from a high-energy fragmentation model. Calculations for mammalian cell cultures show that at high dose, at which intertrack effects become important, protons deliver damage similar to that produced by γ rays, and with fragmentation the relative biological effectiveness (RBE) of protons increases moderately from unity. At low dose, where …
Radiation Risk Predictions For Space Station Freedom Orbits, Francis A. Cucinotta, William Atwell, Mark Weyland, Alva C. Hardy, John W. Wilson, Lawrence W. Townsend, Judy L. Shinn, Robert Katz
Radiation Risk Predictions For Space Station Freedom Orbits, Francis A. Cucinotta, William Atwell, Mark Weyland, Alva C. Hardy, John W. Wilson, Lawrence W. Townsend, Judy L. Shinn, Robert Katz
Robert Katz Publications
Risk-assessment calculations are presented for the preliminary proposed solar minimum and solar maximum orbits for Space Station Freedom (SSF). Integral linear energy transfer (LET) fluence spectra are calculated for the trapped-proton and galactic cosmic ray (GCR) environments. Organ-dose calculations are discussed using the Computerized Anatomical Man model. The cellular track model of Katz is applied to calculate cell survival, transformation, and mutation rates for various aluminum shields. Comparisons between relative biological effectiveness (RBE) and quality factors (QF) for SSF orbits are made, and fluence-dependent effects are discussed.
On The Normalized Yield (Events/Rad/Dalton) Of Biological Molecules Irradiated With Energetic Heavy Ions, Robert Katz
On The Normalized Yield (Events/Rad/Dalton) Of Biological Molecules Irradiated With Energetic Heavy Ions, Robert Katz
Robert Katz Publications
When irradiated with electrons or γ-rays, a number of biological molecules display an approximately linear relationship between the reciprocal of the D37 dose and molecular weight. This is conventionally plotted as a relation between target molecular weight and true molecular weight, where the target molecular weight Mt is given as: Mt × (D37) = α (1) where α is approximately 1010 Da-rad/eV of the energy assumed to be “deposited in the target” in a single “hit” for expression of the end-point. We emphasize that D37 is expressed in rads for we will later …
Cross Sections For Single And Double Strand Breaks In Sv-40 Virus In Eo Buffer After Heavy Ion Irradiation: Experiment And Theory, Robert Katz, S. Wesely
Cross Sections For Single And Double Strand Breaks In Sv-40 Virus In Eo Buffer After Heavy Ion Irradiation: Experiment And Theory, Robert Katz, S. Wesely
Robert Katz Publications
Measured cross sections after heavy ion bombardment, for both single and double strand breaks of SV-40 virus in EO buffer (which emphasizes indirect effects), are consistent with the theory of Butts and Katz for 1-hit detectors.
Cellular Track Model Of Biological Damage To Mammalian Cell Cultures From Galactic Cosmic Rays, Francis A. Cucinotta, Robert Katz, John W. Wilson, Lawrence W. Townsend, John E. Nealy, Judy L. Shinn
Cellular Track Model Of Biological Damage To Mammalian Cell Cultures From Galactic Cosmic Rays, Francis A. Cucinotta, Robert Katz, John W. Wilson, Lawrence W. Townsend, John E. Nealy, Judy L. Shinn
Robert Katz Publications
The quality factor (QF) as defined in International Commission on Radiological Protection report no. 26 (ICRP 26, ref. 1) or in International Commission on Radiation Units and Measurements report no. 40 (ICRU 40, ref. 2) is not expected to be a valid method for assessing the biological risk for deep space missions where the high-energy heavy ion (HZE) particles of the galactic cosmic rays (GCR) are of major concern. No human data for cancer induction from the HZE particles exist, and information on biological effectiveness is expected to be taken from experiments with animals and cultured cells (ref. 3). Experiments …
Radial Distribution Of Dose, Robert Katz, Matesh N. Varma
Radial Distribution Of Dose, Robert Katz, Matesh N. Varma
Robert Katz Publications
The radial distribution of dose about the path of a heavy ion, principally from delta rays, is one of the central contributions of atomic physics to the systematization of high LET radiation effects in condensed matter, whether the detection arises in chemical, physical, or biological systems. In addition to the radial distribution of dose, we require knowledge of the response of the system to X-rays or gamma-rays or to beams of energetic electrons such that the electron slowing-down spectra from these radiations can approximate the slowing-down spectra from delta rays even at different radial distances from the ion's path. A …
Predictions Of Cell Damage Rates For Lifesat Missions, Francis A. Cucinotta, William Atwell, Alva C. Hardy, Michael J. Golightly, John W. Wilson, Lawrence W. Townsend, Judy Shinn, John E. Nealy, Robert Katz
Predictions Of Cell Damage Rates For Lifesat Missions, Francis A. Cucinotta, William Atwell, Alva C. Hardy, Michael J. Golightly, John W. Wilson, Lawrence W. Townsend, Judy Shinn, John E. Nealy, Robert Katz
Robert Katz Publications
Radiological experiments with cell cultures are expected to be performed on Lifesat to study possible gravitational dependence on cellular response. Predictions of cell damage rates for well-studied systems are expected to help guide in the selection of orbits and the design of experiments. In this report we estimate the fractions of cell death and neoplastic transformation of C3H10T1/2 cells (cultured mouse cells) for the proposed Lifesat orbits. The parametric cellular track model of Katz et al. (refs. 1 and 2) is employed using cellular response parameters derived from the experiments of Yang et al. (refs. 3 and 4). The contributions …
Radiosensitivity Parameters For Cell Survival In Tradescantia And For Chromosome Aberrations In Chinese Hamster Cells, Robert Katz, G. Huang
Radiosensitivity Parameters For Cell Survival In Tradescantia And For Chromosome Aberrations In Chinese Hamster Cells, Robert Katz, G. Huang
Robert Katz Publications
Data for the loss of reproductive integrity of Tradescantia stamen hairs irradiated with 250 keV X rays and 0.43 and 5.6 MeV neutrons are fitted with radiosensitivity parameters from track theory, with E0 and m from X-ray data while σ0 and κ are then found from neutron irradiations. The X-ray data display a clear shoulder with 100% survival below 0.18 Gy and a “linear tail.” Data for abnormal metaphases and chromatid exchanges in Chinese Hamster cells have also been fitted with parameters. Parameters for abnormal metaphases are nearly identical with those obtained years ago for cell killing from …
An Analytic Representation Of The Radial Distribution Of Dose From Energetic Heavy Ions In Water, Si, Lif, Nai, And Sio2, Robert Katz, Kim Sum Loh, Luo Baling, Guo-Rong Huang
An Analytic Representation Of The Radial Distribution Of Dose From Energetic Heavy Ions In Water, Si, Lif, Nai, And Sio2, Robert Katz, Kim Sum Loh, Luo Baling, Guo-Rong Huang
Robert Katz Publications
An earlier representation of the radial distribution of dose about the path of a heavy ion in liquid water is modified and extended to include silicon, lithium fluoride, sodium iodide, and silicon dioxide.
Cross Section, Robert Katz
Cross Section, Robert Katz
Robert Katz Publications
In radiobiology the term cross section is used in ways that depart from its original physical meaning. Some of these conceptual extensions represent significant distortions of the original concept. These distortions lead to the misinterpretation of experimental findings.
Particle Tracks In Diverse Media, Robert Katz
Particle Tracks In Diverse Media, Robert Katz
Robert Katz Publications
When energetic heavy ions pass into a medium, they create a trail of excitations, ionizations, and secondary electrons whose effect is represented through their average radial “dose” distribution. The structure of the track depends on this and on the observed “end point.” Tracks may be observed microscopically or through the gross effect of a particle beam. We take the medium to be an assemblage of “targets” whose response to gamma rays is approximated by the cumulative Poisson distribution. While most detectors are 1-hit systems, we have discovered 2-hit and up to 8-hit response. Folding the gamma-ray response into the radial …
The Response Of The Alanine Detector After Charged-Particle And Neutron Irradiations, M. P. R. Waligorski, G. Danialy, Robert Katz
The Response Of The Alanine Detector After Charged-Particle And Neutron Irradiations, M. P. R. Waligorski, G. Danialy, Robert Katz
Robert Katz Publications
Radiosensitivity parameters of track structure theory, representing alanine as a one-hit detector, have been fitted for this free-radical amino-acid system on the basis of the available experimental data on the relative effectiveness of alanine after charged particle and neutron irradiations. The experimental data set can be reproduced by theoretical calculations, roughly to within experimental accuracy. A charged-particle “equivalent radiation” is introduced which can mimic the response of alanine to neutron irradiations. Implications of the results of model calculations for alanine on the shape of the radial distribution of δ-ray dose postulated by track theory, are discussed.
Detector Response To Swift Heavy Ions, Robert Katz
Detector Response To Swift Heavy Ions, Robert Katz
Robert Katz Publications
Track theory is a description of the structure of particle tracks which characterizes the response of many different sorts of "detectors" to energetic heavy ions. It is a parametric rather than a mechanistic description. The medium is a black box containing targets whose response to gamma rays is described by the cumulative Poisson distribution. The response to swift heavy ions is intimately related to the response to gamma rays through the radial distribution of dose about the ion’s path.
Track “Core” Effects In Heavy Ion Radiolysis, Robert Katz, Guo-Rong Huang
Track “Core” Effects In Heavy Ion Radiolysis, Robert Katz, Guo-Rong Huang
Robert Katz Publications
By assuming that HO2● radical production in water and H2 production in benzene are 2 hit processes, and applying the concepts of track physics, we are able to obtain a parametric fit to the yields of these reactions by heavy ion radiolysis from knowledge of the radial dose distribution about a heavy ion’s path. We make no use of the concept of a track core, for no clearly definable track core appears in our calculations of the radial dose distribution. Instead we calculate an action cross section σ from the assumed 2 hit response to γ-rays. The …
Perspectives On The Development Of Track Physics, Robert Katz
Perspectives On The Development Of Track Physics, Robert Katz
Robert Katz Publications
Let me thank all of you for being here, Tony Starace, for having conceived this meeting, and Bob Wood and Matesh Varma, for over 20 years of support without which there would have been no track physics. There are many others to thank: the students, postdoctorates, and senior visitors who actually did all the work, and the many investigators around the world who made measurements that proved to be essential to developing and testing the notions of particle tracks.
This enterprise began when I undertook to rewrite an introductory physics text by Henry Semat to adapt it to a calculus-based …
Robert Katz: A Biographical Sketch, M. Eugene Rudd, John F. Fowler
Robert Katz: A Biographical Sketch, M. Eugene Rudd, John F. Fowler
Robert Katz Publications
Robert Katz was born in 1917 in New York City of Russian- Jewish immigrant parents. He grew up in the Bronx, attended Brooklyn College where he received his B.A. degree in 1937. A year later he was awarded the M.A. degree in physics at Columbia University. During World War II he worked for the Air Force at Wright Field in Ohio. After the war he returned to academia as a graduate student at the University of Illinois, where he earned the Ph.D. degree in physics in 1949. From that year he was a member of the Department of Physics at …
Reply To Lung Cancer Risk From Rn In Chinese Study, Werner Hofmann, Robert Katz, Zhang Chunxiang
Reply To Lung Cancer Risk From Rn In Chinese Study, Werner Hofmann, Robert Katz, Zhang Chunxiang
Robert Katz Publications
We are writing in response to comments by V. A. Archer (Archer 1987) on our study of lung cancer incidence in two Chinese areas, designated as the high background and the control area (Hofmann et al. 1986). In his comments, he asserts that the epidemiological data suffer from two serious defects.
Radiobiological Modeling Based On Track Structure, Robert Katz
Radiobiological Modeling Based On Track Structure, Robert Katz
Robert Katz Publications
Since the interaction of beams of charged particles with targets in physics is customarily based on beam fluence and interaction cross section we have chosen the same logical structure for our radiobiological model.
Proceeding from simple to complex systems we have first constructed and verified a track structure model of observable tracks in nuclear emulsions, then of dry enzymes and viruses, of scintillation counters, of TLD’s, of the Fricke dosimeter as prerequisite to the construction of a valid radiobiological model.
For this model we require 1) knowledge of the average radial distribution of local dose about the path of an …