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Laboratory studies of single cell survival after irradiation with extended Bragg peak helium ions suggest a relative biological effectiveness (RBE) of 1.4 for oxygenated cells. A clinical radiobiological investigation has been initiated using patients with mycosis fungoides. One patient received standard total body electron beam irradiation according to the Memorial Hospital technique, which consists of six weekly doses of 400 rads. Small selected areas were shielded and received single, graduated doses of electron and helium ion extended Bragg peak therapy. Two additional comparable regions received six weekly doses of the two therapeutic beams. Changes in the severity of lesions according to a semi-quantative severity score (SS) were observed following treatment. Values for maximum reduction in the SS observed for the two therapy beams after treatment were consonant with a RBE of 1.4. Recurrence patterns after therapy with the two beams also differed. Lesions treated with the heavy particles remained under control longer than those treated with doses of electrons yielding comparable initial effects. These data suggest that, in addition to processes involved in the increased RBE for helium ions, other factors may be operating to produce a more sustained benefit from extended helium ion Bragg peak irradiation.

Twenty-one patients with mycosis fungoides were given total-body irradiation with 2.5 and 3.5 MeV electrons, using four to six doses of 400 rads each. Prompt symptomatic relief and good long-term control of both ulcerated and nonulcerated lesions were obtained. Regression of lesions between fractions made subsequent treatments more efficient. No untoward immediate or late effects were noted in the irradiated bone marrow or normal skin. A severity scoring system used to evaluate radiation response is described.

The synthesis of a series of model compounds related to poly[2,2-propanebis(4-phenyl)-carbonate] is described. Exposure of these compounds to electron beam irradiation and analysis of the products showed that degradation occurs predominantly at the carbonate grouping; reaction schemes are proposed for the products isolated. On the basis of these results and earlier work the radiation stability of the polymer is attributed mainly to its aromatic character, but it is suggested that radical recombination reactions are an important factor in reducing the degree of chain scission. Die Synthese einer Reihe von Modellsubstanzen fur Poly[2,2-Propan-bis(4-phenyl)-carbonat] wird beschrieben. Last man auf diese Substanzen Elektronenstrahlen einwirken und analysiert die Produkte, so zeigt sich, das der Abbau vornehmlich an der Carbonatgruppe geschieht; fur die isolierten Produkte werden Reaktionsgleichungen angegeben. Auf Grund dieser Ergebnisse und fruherer Arbeiten wird die Stabilitat des Polymeren hauptsachlich seinem aromatischen Charakter zugeschrieben; man kann jedoch auch annehmen, das Radikalrekombinationen einen wichtigen Faktor darstellen, um das Ausmas der Kettenspaltung herabzusetzen.

The effect of megavoltage irradiation with cobalt teletherapy or electron beam therapy has been evaluated in a series of 31 patients with extensive carcinoma of the maxillary antrum. Twelve of these patients were living, free of disease, at three years, and six out of 19 were alive at five years. From these results it seems that radical megavoltage radiation therapy can be relied upon to eradicate squamous carcinoma cells in bone in the management of advanced carcinoma of the maxillary antrum with its ethmoidal, orbital or pterygomaxillary extensions.

A new technique of electron microscopy has been developed which, when applied to the micrography of tobacco mosaic virus, results in a notably improved delineation of its fine structure. The technique stems from earlier observations that the amount of electron beam irradiation normally used in electron microscopy is destructive to biological specimens. A method is described to minimize such damage, wherein the specimen is subjected only to the irradiation necessary to obtain a photographic exposure. The contrast in the appearance of tobacco mosaic virus as micrographed by the new procedures, and by traditional ones, is demonstrated.

ポリエチレンテレフタレートを真空中Van de Graaff型加速器の電子線を照射した場合の効果を,マススペクトル,赤外線吸収スペクトル,溶液粘度,X線回折などによって追求し,加熱分解の場合と比較検討した。線量は107～109radである。低線量照射の場合の発生ガスのマススペクトルは熱分解の場合と同様でかなり複雑であり,多成分の存在を示すが,高線量照射(109rad)においては炭酸ガスと一酸化炭素がその大部分を占める。これらの測定結果からおのおのの発生ガスについてG valueを求め,主鎖切断に要するエネルギーを計算した。照射による分解についてはその末端基が破壊され易いことを認めた。

Electron beam irradiation of cell monolayers at 50 keV produced survival response similar to those for γ-rays, whereas 10-keV beams, which penetrated only to the nuclear periphery, produced responses like those for heavy particles of high linear energy transfer. The results imply that no true threshold dose exists for any form of ionizing radiation.

Alkylnaphthalenes from dodecyl to eicosyl were synthesized and evaluated on characteristics of diffusion pump fluids. A new diffusion pump fluid, whose major component was monoeicosyl-naphthalene, gave very good results as discribed below. The ultimate pressure obtained by a metal pump was 1×10-9 Torr. Oxidation stability test was carried out by introducing air into the pump system up to the atmospheric pressure during operation six times of five minutes and then once for 30 minutes, and the ultimate pressure obtained was 3×10-9 Torr. The backstream of the fluid was 6×-3 mg/min. cm2. Results of the mass spectrometric analysis and observations of the polymerized film formed by electron beam irradiation showed less contamination of eicosylnaphthalene than a silicon fluid.