Local Radiation Effects Research Articles

The Mechanism of Local Radiation Effects

The Mechanism of Local Radiation Effects

Diagnostic and therapeutic use of radioactive iodine.

THE NATURE of the radiations from the iodine isotope, I131, makes it valuable as a source of internal radiation for those tissues which will selectively absorb iodine. Although this radioactive isotope emits both beta and gamma rays, the great majority of the biologic activity is due to the beta particles which are entirely absorbed within a distance of about 2 mm. in tissue. In fact, most of the beta rays travel considerably less than 2 mm. Because the beta energy is absorbed so close to its source, intense local radiation effect occurs wherever I131is concentrated and is limited to this range. The gamma radiation penetrates farther through the tissues. and much of it escapes from the body. The effect which the gamma rays do have on the tissues is thus distributed widely. Consequently, the gamma radiation effect in any area is relatively small. Since gamma rays escape

THE PROCESSES OF HEATING AND COOLING IN A SECTION OF THE IRISH SEA

The heat balance equation is applied to the Holyhead-Dublin Bay section of the Irish Sea. It is shown that the seasonal variation in the heat content of the section as a whole can be accounted for, largely, by the local effects of radiation and exchange of heat with the atmosphere. There is, however, a considerable transfer of heat from the coastal waters towards the centre of the channel in summer and in the reverse direction in winter. Attributing this transfer to mixing due to horizontal turbulance, an estimate is made of the horizontal eddy diffusivity.

The Faculty of Radiologists—Discussion

There are two aspects to the question of the production of general effects in radiotherapy; there are those effects that are intended and thought to be beneficial, and those that are incidental and deleterious. The gap between these two is bridged by the treatment of that group of radiosensitive diseases characterised by hypertrophy of homologous tissues throughout the body rather than by a single malignant focus with a tendency to dissemination. Here radiotherapy produces adequate local effects for the relief of symptoms, but has not proved very successful in supplying general effects that have any fundamental influence on the progress of the disease. The combination of chemotherapy and radiotherapy in this group of diseases may possibly offer some hope for future progress. In the study of the local effects of radiation a combination of observation and experiment has led to advancement in our knowledge, and we have employed a unit of local dose, the rontgen, that has been generally accepted. Experience h...