Archive

  • 28 March 2001 Volume 10 Issue 1
      
  • Select all
    |
  • Research on the Main Factors of Dose Estimation Influenced by Autoradiography
    DAI Guang-fu, WANG Ming-xi, KOU Ming-ying, et al
    2001, 10(1): 1-4.
    Download PDF ( ) HTML   Knowledge map   Save
    Objective In most situations, the spatial locations of radiopharmaceuticals are not uniform, so that in order to estimate the dose to cells and cell nuclei is necessary.Methods Autoradio-graphy (ARG) is a method to obtain the precise spatial information of the (radiolabels, relative to the tissue histology.In the study, the microscopic locations of this) radioactive substance in the liver of mice were investigated through microscopic frozen section ARG, and a mathematical model was developed, which can be conveniently used to microdosimetry, such as estimations of the doses received by the cell nuclei in rat liver after injection of 99mTc-MIBI via tail veins in this test.Results A comparison of the radiation dose rate estimates was conducted between the cellular dosimetry model and MIRD, revealing significant differences.Conclusion ARG was proved to be a useful approach to provide detailed spatial and dosimetric information on radiopharmaceuticals within organs so that we can evaluate precisely the effectiveness of radiotherapy and radiotoxicity and microscopic radiation-effect in nuclear medicine.In this study the influence factors of dose estimation are detail analysed and discussed.
  • Distribution Characteristics of Rn-222 and Rn-220 Concentrations in Air in High Background Radiation Area of Yangjiang, China
    YUAN Yongling, H. Morishima, SHEN Hong, et al
    2001, 10(1): 5-7.
    Download PDF ( ) HTML   Knowledge map   Save
    Objective This paper reports on distribution characteristics of Rn-222 and Rn-220 concentrations in air in investigated areas Methods A pair of passive integrating cup monitors method is used for the measurement of Rn-222 and Rn-220 concentration in air in the High Background Radiation Area (HBRA) and the neighboring Control Area (CA), for one year.Results The concentrations in indoor air of Rn-222 and Rn-220 in the HBRA were still higher significantly than that in outdoor air, while the concentrations in CA were similar between the indoor air and outdoor air.The concentrations in indoor and outdoor air of Rn-222 and Rn-220 from different seasons are no distinct which showed that it is little higher in autumn and winter.it is clear that there are some relationships among concentrations in indoor air of Rn-222 and Rn-220, and external radiation level of households, construction materials in HBRA, while CA did not discover this relationship.The measured data indicate that the distance from wall or height above the ground does not much influence the concentration of Rn-222 in the room.However, they, prominently influence the concentration of Rn-220.The average concentration of Rn-220 measured at 5-10cm from wall was 12.9 times higher than that at 80-100cm;and the average concentration of Rn-220 measured at 5-10cm above the ground was 6.21 times higher than that at 80-100cm above the ground.Conclusion The average indoor concentration of Rn-222 in the HBRA was little higher than the populationweighted average of indoors Rn-222 concentration.The ratio of indoor concentration of Rn-222 between HBRA and CA are 2.6:1.0.The indoor concentration of Rn-220 in HBRA is significantly higher comparing to CA (7.18 times) and the population-weighted average (29.7 times), respectively.The distribution in indoor concentration of Rn-220 in HBRA is very heterogeneous.We noted that Rn-220 and its decay products are very important component of effective dose for the inhabitants living in the HBRA.
  • Radioactive level of Glazed Tiles and Suggestion for Management of Formulating Radidogical Limits
    MAO Ya-hong, LIU Yi-gang, ZHANG Guang, et al
    2001, 10(1): 8-10.
    Download PDF ( ) HTML   Knowledge map   Save
    Objective To lay down the radiological limits to glazed tiles decorated in houses.Methods To Survey the radioactive concentrations of end products and raw and processed materials, radon exhalation rates from the surface of glazed tiles, etc.Then to deduce the limits according to these data and the theory of UNSCEAR 1993.Results The difference between the surface and the base is 102 times.The radon exhalation rates from the surface of the glazed tiles are higher than the rates from the ordinary building materials.etc.Conclusion The activity concentrations of the natural radioactive nuclides in the glazed tiles should be in the range of:CTh/230+CRa/310+CK/3500 ≤ 1.At the same time, the activity concentrations of 226Ra in the glazes be in the range of CRa ≤ 1200.