Biomedical subjects

D Porter

Publications and source records attributed to D Porter.

At least 145 records · Page 8Linked to original sources

PubMed1975

Interaction of gamma-ray and neutron effects on the proliferative capacity of Chinese hamster cells.

The loss of reproductive capacity of Chinese hamster cells has been studied using 60Co gamma-rays and DT neutrons singly or combined in fixed proportions. Surviving fractions were measured down to 2 times 10-4. Interaction between the effects produced by neutrons and gamma-rays in the mixed irradiations has been demonstrated. The results are compared with those predicted by the cellular inactivation model developed by Katz and co-workers from their delta-ray theory of track structure.

Animals↗

PubMed1975

The response of the ferrous sulphate dosemeter to neutrons.

A semi-empirical method of calculating G-values for the ferrous sulphate dosemeter irradiated by neutrons up to 18 MeV has been developed. It utilizes published charged particle G-values along with particle spectra calculated for mono-energetic neutron interactions with the dosemeter medium. All available G-value measurements with neutrons have been evaluated and compared with values predicted by this method. The agreement was excellent for DT generator and cyclotron neutron beams in which the neutron spectra had been accurately determined. However, the predictions could not be completely confirmed for lower energy neutrons becuase of the large experimental uncertainties in the measured G-values and the lack of detailed information on the neutron spectra.

Evaluation Studies as Topic↗

PubMed1975

A novel fast neutron dosemeter based on fission chambers. Part I: Principles of operation and theoretical response in neutron therapy radiation fields.

A novel method is proposed of accurately measuring fast neutron doses of interest in radiotherapy. The technique, which utilizes calculated neutron fluence-to-kerma conversion factors, is based upon the combination of measurements with calibrated neptunium-237 and uranium-238 pulse fission chambers to obtain a response which matches the variation of kerma with neutron energy. The theoretical performance of a practical instrument has been assessed for a variety of neutron spectra to evaluate the spectrum dependence of the dosemeter. The overall systematic uncertainty using this absolute method of determining the neutron dose under charged particle equilibrium conditions is comparable to that encountered with ionization chamber techniques.

Hot Temperature↗

PubMed1974