1982年 · 第02卷第06期

Chromosome aberration following ⁶⁰Coγ-irradiation and mixed n-γ irradiation with different neutron percentages (about 90%, 50% and 15%) has been studied. The yields of dicentrics and acentrics and the percentages of abnormal cells all augmented with the increase of radiation dose. The higher the neutron percentage, the more serious the radiation effect. The data of dicentric yield of all groups fit the potential function Y=kDⁿ, and the value of n decreased with the increase of neutron percentage. The n-value was approximately 2 for γ-irradiation and 1.1 for the mixed irradiation with high ratio of neutrons. The RBE values were calculated and found to be varied with the neutron percentage and the absorbed dose. The higher the neutron percentage and the lower the absorbed dose, the higher the RBE.

The early and late effects of a single or fractionated low dose radiation on the mouse embryoes during different developing stages of preimplantation are reported.

It was found that as for early effects, the number of live or dead fetuses, the early absorption sites, the total implantations and the mean fetal weights per litter were significantly different from the controls, and the prenatal mortality was increased with the radiation doses they received. When the animal received an acute single dose of 100R γ-ray at 2: 00 P. M. on the first day of gestation, the lowest prenatal survial rate was observed. In the late effect group, all animals were observed for two years, and the frequency of leukemia was 4.9 times more than that of the control. The results indicated that embryoes during proliferation stage before implantation were sensitive to radiation.

Two cases of radiaton-induced malignant tumors after radiation therapy for cervical carcinoma are reported. Case 1 was malignant fibrohistiocytoma of right gluteal region, developed after a latent period of 5 years. Local radiation dose was 5, 500 R and intracavitary radiation dose was 16, 000 R. Case 2 was adenocarcinoma of the rectosigmoid colon, developed after a latent period of 8 years. Local radiation dose was 5, 000 R and intracavitary dose was 14, 000 R.

In this paper three cases of plutonium contaminated wounds (two cases of plutonium nitrate burn, one case of stab wound by plutonium metal) are reported. They were treated mainly by wound debridement and extirpation, if needed, of lymph nodes near the wounds. Better results were obtained by concurrent administration of chelating agent. Procedures for handling plutonium contaminated wounds are suggested after reviewing the literature.

In present paper we reported a method of dose estimation and a survey of radiation doses of medical diagnostic X-ray workers and patients during special examinations (cardiac catheterization, encephalography, retrograde pyelography, barium meal, etc.) The average organ dose of the testes, ovaries, mammary glands, bone marrow, lungs, bone surface and thyroid received by X-ray workers and patients on a specificexamination and the effective dose equivalent were estimated, and their resuits provided.

Having made a series of experiments on several X-ray protective materials for medical radiology, the author found that printing zine plate (microcrystal zine plate) could be used as an ideal material; it is economical, more handy for use, and more effective in protection. In the article the author also presents the data on the optimal thickness of various protective materials in an attempt to make more economic use of them in manufacturing X-ray protective devices and equipments.

This paper reports the condition of the radioactive contamination from uranium ores transported by train in some districts along the railway and the measures taken for health Protection.

Fifteen monkeys were exposed to whole body irradiation by ⁶⁰Co with a dosage of 600 rads in order to study the effect of ionizing radiation on their immune functions. The results showed that the total leukocytes, lymphocytes, T and B cell counts and the rate of lymphocyte transformation significantly decreased, but T-cells are more radio sensitive than B-cells. The serum IgG levels significantly reduced on the 10th day after irradiatian, while IgM levels did not show any change after radiation, since the IgM is more radioresistant than IgG. The serum complement levels decreased on the 12th day after irradiation (p<0.05).

The results strongly demonstrated that the immune functions of M. Mulatta were depressed after 600 rad irradiation. This is the reason why animals are susceptible to infection following acute radiation injury.