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Dosimetry for radiobiological experiments using energetic heavy ions

Description: The availability of the Bevalac facility of energetic heavy ions with range greater than the size of small mammals makes possible the determination of the biological effects of relatively well defined high LET, whole body irradiation. With the increasing application of high-energy heavy ions in radiobiology there is a corresponding need to develop reliable techniques of both relative and absolute absorbed dose measurement. This paper describes dosimetry studies by the Health Physics Department of the Lawrence Berkeley Laboratory with activation detectors, ionization chambers, nuclear emulsion, thermoluminescent dosimeters and X-ray film. The application of these techniques to an experiment designed to study the leukemogenic effect of the whole-body irradiation of mice by 250 MeV/amu carbon ions is briefly described. Values of absorbed dose in tissue, obtained during this experiment, with a nitrogen filled ionization chamber and $sup 7$LiF thermoluminescent dosimeters are compared and shown to be in good agreement. As a result of this work a value for the average energy to produce an ion pair (W) in nitrogen by 250 MeV/amu $sup 6+$C ions of 37 +- eV was determined. Values of the efficiency of $sup 7$LiF relative to $sup 60$Co $gamma$-rays for ions with dE/dx in the range 110-260 MeV g$sup -1$ cm$sup 2$ are reported. (auth)
Date: August 30, 1975
Creator: Smith, A.R.; Stephens, L.D. & Thomas, R.H.
Partner: UNT Libraries Government Documents Department

Rat mammary carcinogenesis following neutron- or x-radiation

Description: From effects of neutron irradiation upon cell function; Neuherberg, F. R. Germany (20 Oct 1973). Sprague-Dawley female rats, 61 to 63 days of age, were given a single dose of either 0.10, 0.40, 1.6, or 6.4 rads of 0.43-MeV neutrons, or 28, 56, or 85 rads of 250-kVp x rays, or no radiation in a single experiment. The interim results, either in terms of percent of rats with mammary neoplasia or mean number of mammary neoplasms per rat, at the end of 14 months after irradiation, indicate that 0.10 to 0.40 neutron rads was followed by a mammary neoplastic response much like that following 28 xray rads. The mammary neoplastic response to either 6.4 neutron rads or 56 to 85 x-ray rads was similar. Thus the RBE for neutrons for the induction of mammary neoplasia in the SpragueDawley rat is much larger at low neutron doses than at high doses. (auth)
Date: January 1, 1973
Creator: Shellabarger, C.J.; Kellerer, A.M.; Rossi, H.H.; Goodman, L.J.; Brown, R.D.; Mills, R.E. et al.
Partner: UNT Libraries Government Documents Department

Influence of experimental end points, dose, dose rate, neutron energy, nitrogen ions, hypoxia, chromosome volume and ploidy level on RBE in Tradescantia stamen hairs and pollen

Description: From effects of neutron irradiation upon cell function; Neuherberg, F.R. Germany (22 Oct 1973). Procedures are described for irradiating Tradescantia cuttings with neutrons and x rays. Stamen hairs were scored for various mutations. Results are discussed under the following headings: experimental end points and RBE; influence of dose on RBE; effect of dose rate on RBE; influence of neutron energy on RBE; the RBE of 3.9 GeV nitrogen ions; the influence of hypoxia (OER); and the influence of chromosome volume and ploidy level on RBE; pollen abortion data. Graphs are presented to show survival curves for stamen hairs after neutron and x irradiation and neutron and x-ray dose-response curves for pink mutants, blue giant cells. and colorless mutants. (HLW)
Date: January 1, 1973
Creator: Underbrink, A.G. & Sparrow, A.H.
Partner: UNT Libraries Government Documents Department

Relation between mutation yield and cell lethality over a wide range of x ray and fission neutron doses in maize

Description: From effects of neutron irradiation upon cell function; Neuherberg, F. R. Germany (22 Oct 1973). Seeds of maize were exposed to x rays at a dose rate of 1658 to 1845 rad/min; other seeds were exposed to fission neutrons at a dose rate of 27.5 to 198 rad/min. The irradiated seeds and controls were sown in moist soil. When mature the fourth and fifth seedling leaves were harvested and scored for frequency of yellow-green sectors. Tables and graphs are presented to show dose-response data for frequency of yellow-green sectors per leaf, frequency of mutations as a function of absorbed dose, neutron-induced yield of mutations and RBE of neutrons in comparison to x radiation. (HLW)
Date: January 1, 1973
Creator: Smith, H.H.; Rossi, H.H. & Kellerer, A.M.
Partner: UNT Libraries Government Documents Department

Future research in mouse radiation genetics

Description: From thirteenth international congress of genetics; Berkeley, Ca1ifornia, USA (20 Aug 1973). The specific-locus method was used to investigate the effect of various biological and physical factors on radioinduced mutation frequency at a sample of seven gene loci of mice. The biological factors include sex, cell stage, and the interval between irradiation and fertilization. The physical factors include radiation dose, dose rate, dose fractionation, and radiation quality. It is suggested that the studies be extended to determine the effects of the various biological and physical factors on mutation frequency at low radiation dose rates in mouse spermatogonia and dictyate oocytes; investigations on the actual nature and effect of the individual mutations induced by radiation; and studies on the nature, extent, and persistence of the actual anatomical and physiologica1 damage expressed in the descendents of irradiated populations. (CH)
Date: January 1, 1972
Creator: Russell, W.L.
Partner: UNT Libraries Government Documents Department

Ultraviolet-inactivation of conidia from heterokaryons of Neurospora crassa containing uv-sensitive mutations

Description: From 7th neurospora information conference; Asilomar, California, USA (25 Mar 1974). The effect of three uv-sensitive mutations of Neurospora crassa, upr-1, uvs-4 and uvs-6, on the ultraviolet-inactivation of conidia from two- component heterokaryons was investigated. In twocomponent heterokaryons with wild-type sensitivity to radiation inactivation, all three conidial fractions exhibited similar ultraviolet-inactivation curves. Each uv-sensitive mutation studied uniquely modified the ultraviolet-inactivation curves of conidia from two- component heterokaryons. In heterokaryons heterokaryotic for upr-1, the upr-1 mutation was recessive and the repair function determined by the wild-type allele was functional to some degree in homokaryotic upr-1 conidia. All three conidial fractions of heterokaryons containing upr-1 in both components showed increased sensitivity to ultraviolet light. The uvs-4 mutation was recessive and resulted in conidia with increased uv-sensitivity only when included in both components of a heterokaryon. Homokaryotic uvs-4 conidia, which arose from heterokaryons containing both uvs-4 and wild-type components, exhibited wild-type survival. Therefore, as with upr-1, there was a carryover of the repair capability to conidia which were genetically uv-sensitive. The uvs-6 mutation, when included in one component of a two-component heterokaryon, resulted in increased uv- sensitivity of both heterokaryotic and homokaryotic uvs-6 conidia. When both components contained uvs-6, the uv-sensitivity of all three conidial fractions was increased and all showed similar inactivation curves. Thus, as with upr-1 and uvs-4, there was a carryover of the wildtype repair capability to geneticaily uvs-6 conidia. Heterokaryon tests for complementation between two non-allelic uv- sensitive mutations showed that in heterokaryotic conidia, complete complementation occurred between upr-1 and uvs-4. (auth)
Date: January 1, 1973
Creator: Shelby, M.D.; de Serres, F.J. & Stine, G.J.
Partner: UNT Libraries Government Documents Department

Dose-effect relations

Description: No Description Available.
Date: July 1, 1974
Creator: Roesch, W C
Partner: UNT Libraries Government Documents Department