[en] Growing knowledge about the size of biological model parameters for the initiation of cancer by radiation makes it of current interest to study physical influence parameters beyond dose and LET (Linear Energy Transfer), such as the detailed distribution of ionizations along an electron track. We have refined our earlier calculation of the electron track structure by deriving expressions for the ionization cross section and the LET, which give results in excellent agreement with all the available data on differential and integrated ionization cross sections, LET and energy per ion-pair. The result is a reliable expression for the distribtion of ionizations along the main track of a beta ray, as well as on the resulting delta rays up to fourth order

[en] Observations are presented on bone microradiograms from 44 radium patients. The data cover three basic categories of mineral changes: (1) increase in bone mineral resorption, (2) increase in bone mineral density and (3) increase in new bone tissue formation. The data show a trend of increasing amount of mineral change in all three categories as the cumulative rads, cumulative rad-years, and amount of radium intake increase

[en] Separate abstracts were prepared for 12 of 33 papers, and 1 of the 2 appendices in this annual report of the Center for Human Radiobiology. The other papers were represented by abstracts only

[en] The determination of Sc and seven rare earth elements, Nd, Sm, Dy, Ho, Eu, Tm, and Yb, in biological samplesby atomic absorption spectrophotometric analysis (AAS) using electrothermal atomization in a pyrolytic graphite tube is shown to be rapid, precise and accurate. The technique utilizes the method of standard additions and linear regression analysis to determine results from peak area data. Inter-elemental interferences are negligible. The elements found sensitive enough for this type of analysis are, in order of decreasing sensitivity, Yb, Eu, Tm, Dy, Sc, Ho, Sm and Nd. The determination in these types of materials of Gd and elements less sensitive to AAS detection than Gd does not appear to be feasible. Results are presented on the concentrations of these elements in 41 samples from human subjects, cows and vegetables with normal environmental exposure to the rare earth elements. The composite percent mean deviation in peak-area readings for all samples and all elements examined was 4%. The mean standard error in the results among samples was about 6.5%

[en] Atomic absorption spectrophotometry (AAS) employing electrothermal atomization in a pyrolytic graphite tube is shown to be a precise and accurate method for analysis of 11 rare earth, or rare-earth-like elements in air filter samples taken in a thorium and rare earth refinery. The method is fairly rapid since it involves only fluoric acids. Each element was sequentially analyzed from the same resulting solution by using either the techniques of standard-curve calibration or that of standard additions. The two methods used on the same sample gave essentially identical results (composite ratio for 171 such trials being 0.9996). Matrix effects were negligible and no background correction was necessary. The average percent standard deviation for all duplicate trials (176) was 4.2%. Elements analyzed by this method were La, Nd, Sm, Eu, Gd, Dy, Ho, Tm, Yb, Gd, Sc and Y. Other rare earths such as erbium (Er), lutetium (Lu), and terbium (Tb), with comparable analytical sensitivity by AAS to Dy, Sm, and Nd, respectively, could presumably be analyzed by this method as well

[en] A new sampling can is described for collecting an air sample for determination of its radon content. Instruments which are employed for the continuous monitoring of radon or its daughters in houses are described and their performances discussed

[en] The retention of neptunium in liver and bone subsequent to its gastrointestinal absorption has been determined in both fasted and fed mice. The values obtained for fractional retention were 3 x 10^-₃ and 1 x 10^-₄, respectively, and are within a factor of two the same as those for plutonium in fasted and fed mice

[en] The deposition rates of radon daughters on indoor surfaces have been measured by exposing the window of a proportional counter to the air of a house with high concentrations of radon and its daughters. Deposition velocities for unattached ₂₁₈Po (RaA) and ₂₁₄Pb (RaB) of approximately 4 mm sec^-₁ were obtained by dividing the deposition rates by the concentrations of unattached daughters in the air. These results agree with those obtained by other workers but are dependent on the assumptions made about the fractions of the daughters which are attached to the atmospheric aerosol

[en] Available data were analyzed to determine the relative systemic intakes of ₂₂₈Ra and ₂₂₆Ra in Radium Dial Co. workers. The data suggested an activity ratio of ₂₂₈Ra to ₂₂₆Ra of 0.16 +- 0.08 (standard deviation) for systemic intakes occurring in the years 1921 to 1924 and negligible exposure to ₂₂₈Ra after 1924

[en] The topic of health effects of radium has recently been considerably broadened by the identification of multiple myeloma as a specific outcome of bone-seeking radionuclides, and by evidence that the incidence of breast cancer may be significantly increased by radium exposure. All soft-tissue tumors are now suspect, especially leukemias. Concepts of dose-response need to be broadened to include the concept of risk factors, or, if one prefers, of susceptible subgroups. Biological factors relating to radium uptake and retention require study, as do risk factors modifying risk of both the classical tumors, osteosarcoma and nasal sinus/mastoid, and the more recently suspect soft-tissue tumors. The history, organization, and current research activities in epidemiology at Argonne National Laboratory are described, and findings of the last decade and a half reviewed. Plans for future research are briefly discussed