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Dr. Robert Katz (1917-2011), Obituary

Robert Katz Publications

Dr. Robert Katz, 7/17/17–3/12/11, emeritus professor of physics at the University of Nebraska, died peacefully at his home Saturday March 12th following a brief illness. ... A memorial gathering will be held at 4, Friday, April 1st at the Unitarian Church, 6300 'A' Street, Lincoln.

In Memoriam: Robert Katz (1917–2011), M. P. R. Waligorski, Francis A. Cucinotta

Robert Katz Publications

Bob Katz will be well remembered for his enthusiasm and strong personality. In a scientific dispute, few indeed could match his wit or his sense of humor or survive the cutting logic of his arguments. To those who had appreciation for his science and his personality, he was truly a great scientist and a master teacher. There are many people around the world who will remember Bob Katz for what he offered them and for the way he showed them what truth in science is.

The Katz Model, developed at that time for solid-state detectors and for cell cultures, relates …

Bibliography Of Robert Katz Publications

Robert Katz Publications

150+ Articles (1943-2002)
186 Abstracts (1953-2002)
15 Books and Technical Reports
3 U.S. Patents

Commentary: The Parameter-Free Track Structure Model Of Scholz And Kraft For Heavy-Ion Cross Sections, Robert Katz

Robert Katz Publications

The "parameter-free", "local effects" theory of Scholz and Kraft is an extension to mammalian cells of the theory of RBE for dry enzymes and viruses of Butts and Katz. Its claim for parameter freedom has been challenged elsewhere. Here we examine its conceptual base and find errors in its use of the physical concept of cross section and its neglect of the radiobiological relationship between target size and radio-sensitivity in evaluating the radiation damage to "point targets".

Low Fluence, Robert Katz, F. A. Cucinotta

Robert Katz Publications

The question of the appropriate extrapolation to low dose has long been a subject of controversy. A linear no-threshold model is favored by regulatory bodies as the basis of RBE assignments and estimates of radiation hazards to the general population. This model is largely supported by extensive application of the linear-quadratic survival formula "fitted" statistically to a wide variety of experimental data obtained at doses typically exceeding 1 Gy, and then extrapolated to mGy for practical applications, and even to the prediction of hazards from single electrons. Such extrapolations are questionable at best, and may even prove hazardous for risk …

Chemical Bonds Broken In Latent Tracks Of Light Ions In Plastic Track Detectors, R. Barillon, M. Fromm, Robert Katz, A. Chambaudet

Robert Katz Publications

When a swift ion is slowed down through a plastic detector it creates a latent track. In nuclear track detectors, this latent track can be specifically etched by an appropriate chemical solution. This enlargement process is due to a higher etch velocity (V_T) along the ion's path than in the non-damaged part of the detector. The etched track velocity is definitely linked to the damage created by the incoming ion in the detector material. A relationship between the physical parameters of the energy deposition and the variation in this etched track velocity with the ion energy cannot easily …

Transport Of Space Environment Electrons: A Simplified Rapid-Analysis Computational Procedure, John E. Nealy, Brooke M. Anderson, Francis Cucinotta, John W. Wilson, Robert Katz, C. K. Chang

Robert Katz Publications

A computational procedure for describing transport of electrons in condensed media has been formulated for application to effects and exposures from spectral distributions typical of electrons trapped in planetary magnetic fields. The procedure is based on earlier parameterizations established from numerous electron beam experiments. New parameterizations have been derived that logically extend the domain of application to low molecular weight (high hydrogen content) materials and higher energies (~50 MeV). The production and transport of high energy photons (bremsstrahlung) generated in the electron transport processes have also been modeled using tabulated values of photon production cross sections. A primary purpose for …

Implications Of Single-Particle Experiments For Track Theory, Therapy And Radiation Protection, Robert Katz, Francis Cucinotta

Robert Katz Publications

‘‘Because the predominant exposure of cells in humans is to single isolated tracks, a critical question is what effects a single track is capable of producing and with what probabilities.’’ ‘‘Most of the current biophysical models. . . make the clear prediction that a single track can produce virtually all of the detrimental stochastic effects of interest.’’ ‘‘But one model, in particular (the amorphous track model of Katz and coworkers), disagrees fundamentally that a single low LET track has the ability to cause the cellular changes.’’ ‘‘This model leads to very dramatic differences in the predicted risk at low doses. …

Ion-Kill Dosimetry, Robert Katz, F. A. Cucinotta, M. Fromm, A. Chambaudet

Robert Katz Publications

Unanticipated late effects in neutron and heavy ion therapy, not attributable to overdose, imply a qualitative difference between low and high LET therapy. We identify that difference as ‘ion kill’, associated with the spectrum of z/β in the radiation field, whose measurement we label ‘ion-kill dosimetry’.

Track Theory Predictions For Single-Hit Cell Survival, Robert Katz, Francis Cucinotta

Robert Katz Publications

The track theory of cell survival after heavy-ion irradiation is based on the probability of survival after a single-particle transit, called ‘‘ion-kill’’ (not track core), joined to the cumulative effect of δ rays from adjacent ions in a beam, called ‘‘gamma-kill’’ (not penumbra). The model offers a set of equations containing four parameters, E₀ and m for the single-hit multitarget statistical model for gamma-kill, and additionally σ₀ and κ for ion-kill. A single set of parameters is used to fit a family of survival curves obtained with ions of different LET simultaneously.

Applications Of Amorphous Track Models In Radiation Biology, Francis Cucinotta, Hooshang Nikjoo, Dudley A. Goodhead

Robert Katz Publications

The average or amorphous track model uses the response of a system to gamma-rays and the radial distribution of dose about an ion’s path to describe survival and other cellular endpoints from proton, heavy ion, and neutron irradiation. This model has been used for over 30 years to successfully fit many radiobiology data sets. We review several extensions of this approach that address objections to the original model, and consider applications of interest in radiobiology and space radiation risk assessment. In the light of present views of important cellular targets, the role of target size as manifested through the relative …

Tracks To Therapy, Robert Katz, F. A. Cucinotta

Robert Katz Publications

Studies of the structure of particle tracks have led to models of track effects based on radial dose and radiobiological target theory that have been very successful in describing and predicting track effects in physical, chemical, and biological systems. For describing mammalian cellular inactivation two inactivation modes are required, called gamma-kill aid ion-kill, the first due to synergistic effects of delta rays from adjacent ion paths thus resembling the effects from gamma rays, and the second to the effects of single ion transits through a cell nucleus. The ion-kill effect is more severe, where the fraction of cells experiencing ion …

Radial Distribution Of Electron Spectra From High-Energy Ions, Francis A. Cucinotta, Robert Katz, John W. Wilson

Robert Katz Publications

The average track model describes the response of physical and biological systems using radial dose distribution as the key physical descriptor. We report on an extension of this model to describe the average distribution of electron spectra as a function of radial distance from an ion. We present calculations of these spectra for ions of identical linear energy transfer (LET), but dissimilar charge and velocity to evaluate the differences in electron spectra from these ions. To illustrate the usefulness of the radial electron spectra for describing effects that are not described by electron dose, we consider the evaluation of the …

Track Structure Model For Radial Distributions Of Electron Spectra And Event Spectra From High-Energy Ions, F. A. Cucinotta, Robert Katz, J. W. Wilson

Robert Katz Publications

An analytic method is described for evaluating the average radial electron spectrum and the radial and total frequency-event spectrum for high-energy ions. For high-energy ions, indirect events make important contributions to frequency-event spectra. The method used for evaluating indirect events is to fold the radial electron spectrum with measured frequency-event spectrum for photons or electrons. The contribution from direct events is treated using a spatially restricted linear energy transfer (LET). We find that high-energy heavy ions have a significantly reduced frequency-averaged lineal energy (YF) compared to LET, while relativistic protons have a significantly increased YF and dose-averaged lineal energy (YD) …

Simulation Of A Microdosimetry Problem: Behavior Of A Pseudorandom Series At A Low Probability, P. Meyer, J. E. Groetz, Robert Katz, M. Fromm, A. Chambaudet

Robert Katz Publications

The carcinogenic effects for low dose irradiations are not very well known. Estimations usually are made based on the effects observed at high doses that are then extrapolated to low doses. To estimate low dose effects, the ICRP (International Commission on Radiological Protection) uses a linear extrapolation matched with a dose-rate reduction factor equal to two. This proportionality of the effect and dose, even for the lowest doses and dose-rates, leads to two assumptions which must be questioned :
1. the efficiency of DNA repair in cells does not vary with the dose and the dose-rate,
2. when one single …

Calculation Of Heavy Ion Inactivation And Mutation Rates In Radial Dose Model Of Track Structure, Francis A. Cucinotta, John W. Wilson, Mark R. Shavers, Robert Katz

Robert Katz Publications

In the track structure model, the inactivation cross section is found by summing an inactivation probability over all impact parameters from the ion to the sensitive sites within the cell nucleus. The inactivation probability is evaluated by using the dose response of the system to gamma rays and the radial dose of the ions and may be equal to unity at small impact parameters. We apply the track structure model to recent data with heavy ion beams irradiating biological samples of E. Coli, Bacillus Subtilis spores, and Chinese hamster (V79) cells. Heavy ions have observed cross sections for inactivation that …

Radial Dose Model Of Ssb, Dsb, Deletions And Comparisons To Montecarlo Track Structure Simulations, Francis A. Cucinotta, H. Nikjoo, J. W. Wilson, Robert Katz, D. T. Goodhead

Robert Katz Publications

The initial lesions formed in DNA by ionizing radiation include base damage, single strand breaks (SSB), double strand breaks (DSB), DNA cross links, and deletions. Deletions occur through energy deposition and perhaps more importantly through recombination repair of DSB's. Several mechanisms for the formation of DSB's and deletions related to energy deposition can be considered. Track simulation codes have indicated the importance of clusters of ionizations in small volumes similar to the size of a nucleosome. These clusters have been related to several types of damage to DNA, including DSB and deletions resulting from multiple DSB's formed by single electron …

Track Structure And Radiation Transport Model For Space Radiobiology Studies, F. A. Cucinotta, J. W. Wilson, Robert Katz, W. Atwell, G. D. Badhwar, M. R. Shavers

Robert Katz Publications

Radiobiology experiments performed in space are deemed necessary for validation of risk-assessment methods. The understanding of space radiobiology experiments must combine knowledge of the space radiation environment, radiation transport, and models of biological response. The heavy ion transport code HZETRN has recently been combined with improved models of the galactic cosmic rays (GCR) and extensive comparisons made to measurements on the space shuttle with a tissue equivalent, proportional counter. HZETRN was also coupled with track-structure models of biological damage from heavy ions. Track-structure calculations using improved models of the radial dose distribution around the path of heavy ions provide a …

The Calculation Of Radial Dose From Heavy Ions: Predictions Of Biological Action Cross Sections, Robert Katz, Francis A. Cucinotta, C. X. Zhang

Robert Katz Publications

The track structure model of heavy ion cross sections was developed by Katz and co-workers in the 1960s. In this model the action cross section is evaluated by mapping the dose-response of a detector to γ rays (modeled from biological target theory) onto the radial dose distribution from 6 rays about the path of the ion. This is taken to yield the radial distribution of probability for a "hit" (an interaction leading to an observable end-point). Radial integration of the probability yields the cross section. When different response from ions of different Z having the same stopping power is observed …

Thindown In Biological 1-Hit Detectors: E. Coli B/R And Bs-1*, Zhang Chunxiang, Robert Katz

Robert Katz Publications

According to the theory of Butts and Katz and the new radial dose distribution of Zhang et al., we have calculated inactivation cross sections for the heavy ion bombardment of E. Coli B/r and Bs-1 which w& in agreement with the measurements of Scliafer et made with ions from O to U at energies from 1.5 to 19.5 MeV/u. The data display "thindown", and the decrease in cross section with an increase in stopping power is accompanied by a decrease in energy of a bombarding ion. Following an earlier analysis of heavy ion bombardments of these E. Coli mutants with …

Low Dose, Robert Katz, Francis A. Cucinotta

Robert Katz Publications

Low doses of radiation are frequently inferred to mean doses of the order of 10-100 mGy, regardless of the end point or the nature of the irradiation, as if the energy were deposited uniformly through all targets. Yet, the fluence in a charged particle beam at which there is an average of 1 charged particle transit per target leaves 37% of the targets untouched. At an average of 3 transits per target, 5% of the targets experience no particle transits. Only at an average of 5 transits per target do 99% of the targets achieve one or more transits. One …

Heavy Ion Track-Structure Calculations For Radial Dose In Arbitrary Materials, Francis A. Cucinotta, Robert Katz, John W. Wilson, Rajendra R. Dubey

Robert Katz Publications

The δ-ray theory of track structure is compared with experimental data for the radial dose from heavy ion irradiation. The effects of electron transmission and the angular dependence of secondary electron ejection are included in the calculations. Several empirical formulas for electron range and energy are compared in a wide variety of materials in order to extend the application of the track-structure theory. The model of Rudd for the secondary electron spectrum in proton collisions, which is based on a modified classical kinematics binary encounter model at high energies and a molecular promotion model at low energies, is employed. For …

Effects Of Track Structure And Cell Inactivation On The Calculation Of Heavy Ion Mutation Rates In Mammalian Cells, Francis Cucinotta, J. W. Wilson, M.R. Shavers, Robert Katz

Robert Katz Publications

It has long been suggested that inactivation severely effects the probability of mutation by heavy ions in mammalian cells. Heavy ions have observed cross sections of inactivation that approach and sometimes exceed the geometric size of the cell nucleus in mammalian cells. In the track structure model of Katz the inactivation cross section is found by summing an inactivation probability over all impact parameters from the ion to the sensitive sites within the cell nucleus. The inactivation probability is evaluated using the dose-response of the system to γ-rays and the radial dose of the ions and may be equal to …

Effects Of Track Structure And Cell Inactivation On The Calculation Of Heavy Ion Mutation Rates In Mammalian Cells, Francis A. Cucinotta, J. W. Wilson, M. R. Shavers, Robert Katz

Robert Katz Publications

It has long been suggested that inactivation severely effects the probability of mutation by heavy ions in mammalian cells. Heavy ions have observed cross sections of inactivation that approach and sometimes exceed the geometric size of the cell nucleus in mammalian cells. In the track structure model of Katz the inactivation cross section is found by summing an inactivation probability over all impact parameters from the ion to the sensitive sites within the cell nucleus. The inactivation probability is evaluated using the dose-response of the system to γ-rays and the radial dose of the ions and may be equal to …

Reply To D. E. Watt, A. S. Alkharam, M. B. Child And M. S. Salikin, “Dose As A Damage Specifier In Radiobiology For Radiation Protection." A Comment On "Dose" (Radiat. Res. 137, 410-413, 1994), Robert Katz

Robert Katz Publications

The authors are generous in observing that "the high degree of success achieved by (Katz's δ-ray theory of track structure) in fits to survival curves for heavy ions, and in analysis and prediction of other biological effects is almost legend." We remind them that the model is physical, and has little to do with biology in an explicit way, except that an oversimplified "bean bag" model of a eukaryotic cell is used, in which the bag represents the cell nucleus and the beans represent internal targets. No explicit biologically mechanistic structure or response is inferred. No reference is made to …

On The Linear Extrapolation To Low Doses, Robert Katz, Michael P. R. Waligórski

Robert Katz Publications

While radiobiological data are conveniently fitted by a linear quadratic formula to data of limited dynamic range at doses typically exceeding 1 Gy, they are extrapolated linearly to doses below a milligray for the evaluation of low dose RBEs. However a single relativistic electron passing through a cell nucleus deposits a “dose” there in the neighborhood of a milligray. The validity of the linear extrapolation then rests on the demonstration that a single electron transit through a cell nucleus can cause inactivation or mutation or can lead to cancer induction. The extrapolation made is a huge one, of some three …

Dose, Robert Katz

Robert Katz Publications

The universal use of dose as a normalizing parameter in radiobiology is based entirely on the availability of measuring instruments. It is a poor basis for predicting or understanding the relationship between an irradiation and the resulting end point. Energy deposited is not the cause of an interaction. It is a secondary effect. The interaction is best described by fluence and cross section. Energy deposited depends principally upon inelastic collision cross sections for the interaction of electrons with molecules. Especially for heavy-ion bombardments, for high-LET radiations, inelastic electron collision cross sections relate only remotely to the observed end points of …

Radiosensitivity Parameters For Lethal Mutagenesis In Caenorhabditis Elegans, F. A. Cucinotta, J. W. Wilson, Robert Katz

Robert Katz Publications

For the first time track structure theory has been applied to radiobiological effects in a living organism. Data for lethal mutagenesis in Caenorhabditis elegans, obtained after irradiation with nine different types of ions of atomic number 1-57 and gamma rays have yielded radiosensitivity parameters (E₀, σ₀, K, m = 68 Gy, 2.5 x 10^-9 cm², 750, 2) comparable with those found for the transformation of C3HT10 1/2 cells (180 Gy, 1.15 x 10^-10 cm², 750, 2) but remote from those (E₀ and σ₀ = ≈2 Gy, ≈5 …

Survey Of Cellular Radiosensitivity Parameters, Robert Katz, Rashidah Zachariah, Francis A. Cucinotta, Chunxiang Zhang

Robert Katz Publications

A model of the formation of particle tracks in emulsion has been extended through the use of biological target theory to formulate a theory of the response of biological cells and molecules of biological importance to irradiation with energetic heavy ions. For this purpose the response to γ rays is represented by the single-hit, multi-target model with parameters m and D₀, while additional parameters κ (or a₀) and σ₀ are required to represent the size of internal cellular targets and the effective cross-sectional area of the cell nucleus, respectively, for heavy-ion bombardments. For one-or-more-hit detectors, …

Cellular Track Model For Study Of Heavy Ion Beams, Judy L. Shinn, Robert Katz, Francis A. Cucinotta, John W. Wilson, Duc M. Ngo

Robert Katz Publications

Track theory is combined with a realistic model of a heavy ion beam to study the effects of nuclear fragmentation on cell survival and biological effectiveness . The effects of secondary reaction products are studied as a function of depth in a water column. Good agreement is found with experimental results for the survival of human T-1 cells exposed to monoenergetic carbon, neon, and argon beams under aerobic and hypoxic conditions. The present calculation, which includes the effect of target fragmentation, is a significant improvement over an earlier calculation because of the use of a vastly improved beam model with …