Biomedical subjects
Publications and source records attributed to M Rozenfeld.
Eccrine poromatosis (EP) of remarkable severity has been observed in a patient with hidrotic ectodermal dysplasia (HED), a member of the kindred originally described by Clouston. Neither the EP nor its association with HED has been previously reported.
Afterloading techniques were developed for the in vivo assessment of the RBE of californium-252 with respect of radium-226 using a fibrosarcoma in mice. The afterloading holder positions sources so that the tumor is uniformly irradiated. Using the end points of tumor volumetric studies up to 150 days after irradiation, it was found that the RBE ranged from 5-8 at clinically relevant dose rates and total doses.
Readings made with condenser-ionization chamber systems are frequently suspect because significant changes in calibration can occur without being evident in the normal use of the instruments. These changes can be traced to physical causes that alter the voltage sensitivity of electrical capacitance. Thus, measurement of these electrical parameters will indicate whether or not a change in calibration has occurred. Formulas are presented of calculating such changes and determining which parameter is responsible. Good agreement was obtained between the results of calculations with these formulas and the results of radiation measurements made with a Victoreen Condenser R-Meter after several components had been deliberately maladjusted.
Our investigations of an iso-octane-filled liquid-dielectric ionization chamber indicate that this dosimeter is well suited for the measurement of dose distributions at distances close to 252Cf interstitial implant sources. Initial research has shown that such an instrument provides good discrimination between the radiation components of a mixed field and possesses excellent sensitivity. Calculations indicate that iso-octane will yield a neutron and gamma-ray dose response independent of energy over a major part of the 252Cf spectral range, while transmission measurements have demonstrated that the liquid causes little perturbation of the radiation field.