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  • 28 March 2000 Volume 9 Issue 1
      
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  • Measurement of 222Rn、220Rn and their decay products in high background radiation area in Yangjiang
    YUAN Yongling, et al
    2000, 9(1): 1-3.
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    The investigators have measured concentrations of Rn-222, Rn-220 and their decay products in high background radiation area (HBRA) and the neighboring control area (CA), as well as the equilibrium factor F for Rn-222. The average concentrations of Rn-222 in the air indoors and outdoors in the HBRA are 42.6 and 17.3Bq/respectively, and CA, 13.2 and 11.7 Bq/m3, respectively. The average α-potential energy concentrations for daughters of Rn-222 indoors and outdoors in HBRA are 0.109 and 0.051μJ/m3, CA, 0.045 and 0.041μJ/m3, respectively. The average α-potential energy values for daughters of Rn-220 indoor and outdoor in HBRA are 0.249 and 0.053 μJ/m3, CA, 0.051 and 0.025 μJ/m3, respectively. With regard to equilibrium factor F for Rn-222, we have also measured 52 points of 10 hamlets in HBRA (indoor 31, outdoor 21), 9 points of 2 hamlets in CA (indoor 5, outdoor 4), respectively. These figures are 0.46, 0.53, 0.62 and 0.64, respectively.
  • Environmental impact assessment for the apparatus of positron emission tomograph and cyclotron
    Yu shui, et al
    2000, 9(1): 4-5.
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    In this paper, cyclotron, type RDS 111, produced by CTI incorporation, was used as an exemple. According to the characteristic of the radiation source term, the environmental impacts of the apparatus working in normal and abnormal conditions were assessed.
  • The change of the pathology and anti-oxidase in the tumor-bearing mice liver with low dose irradiation
    Feng Leping, et al
    2000, 9(1): 6-7.
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    Objective: To understand the change of tumor-bearing mice malignant tissue pathology and liver antioxidase. Method: Using enzymological and pathological analysis to study the active of SOD、GSH-Px, content of LPO in liver as well as the change of carcinoma tissue. Results: The study shown that the active of antioxidose in liver were aroused for the tummor-bearing mice whosewhole bady pre-exposed to 50 mGg low dose X-ray. The level of MDA was reduced. In the condition of large dose X-ray local irradiation radiotherapy increased gradually after low dose irradiation, the active of the SOD and GSH-Px showed a tendency of increase more than that of contrast groups. At that time the content of the MDA reached that of contrast group. Under optical microscope many lgmphocytes were found to be invoded by the neighbovring malignant tissnes, capillaries, to be dilated and hyperemia occurred. Conclusion: Low dose irradiation can stimulate the active of antioxi dase system in liver of tumor-bearing mice and enhance it to high; Under the condition of large dose radiotherapy SOD、GSH-Px can be induced by the pre-exposed 50mGy low dose irradiation, on the contrary, LPO be reduced; Low dose irradiation can promote the effect of radiotherapy and play a role as radioprotect effect on the normal physiological function.