Archive

  • 28 June 2002 Volume 11 Issue 2
      
  • Select all
    |
  • Estimation of Doses to the Residents Arising from Inhalation of Rn-222, Rn-220 and Their Decay Products in High Background Radiation Area of Yangjiang
    YUAN Yong-ling, H. Morishima, SHEN Hong, et al
    2002, 11(2): 65-68.
    Download PDF ( ) HTML   Knowledge map   Save
    Objective This paper reports on the estimate of average annual effective dose of the residents and absorbed dose in some human tissues and organs arising from inhalation of Rn-222, Rn-220 and their decay products in investigated areas.Methods In order to calculate equilibrium factor F for Rn-222 and equilibrium equivalent concentration of Rn-220, we measure concentration of Rn-222 and Rn-220 by discrete sampling.Meanwhile, we measure the concentration of decay products of Rn-222 and Rn-220.Based on the equilibrium factor F of Rn-222 and equilibrium equivalent concentration of Rn-220, and the occupancy factor, writer estimated average annual effective doses and absorbed doses in some tissues and organs to the residents arising from inhalation of Rn-222, Rn-220 and their decay products in investigated areas.Results The data based upon the results of integrated measurements on the concentration of Rn-222 and Rn-220 in investigated areas.The average indoor and outdoor concentrations of Rn-222 are 49.61 Bq·m-3 and 17.30 Bq·m-3 in HBRA, respectively, and 18.1 and 11.7 Bq·m-3 in CA, respectively.The average indoor and outdoor concentrations of Rn-220 are 95.16 Bq·m-3 and 9.3 Bq·m-3 in HBRA, respectively, and 12.4 and 8.1 Bq·m-3 in CA, respectively.The averages of equilibrium factors of Rn-222 for indoors and outdoors in HBRA are 0.46 and 0.53, respectively.The values in CA are 0.62 for indoors and 0.63 for outdoors, respectively.The value of equilibrium equivalent concentration of Rn-220 for indoors and outdoors in HBRA are 6.51 Bq·m-3 and 0.79 Bq·m-3, respectively, and the values for CA are 0.66 Bq·m-3 and 0.33 Bq·m-3, respectively.Conclusion The estimate of average annual effective dose to the residents arising from inhalation of Rn-222, Rn-220 and their decay products was 3.28 mSv·a-1 in HBRA, while that in CA was 1.03 mSv·a-1.The trachea-bronchial tree has the maximum absorbed dose in HBRA, the value is 5.40 mGy·a-1;lung has the second absorbed dose, the value is 1.08 mGy·a-1.These two values are about 4.0 times in CA.The estimate of average annual effective dose to the residents arising from inhalation of Rn-220 and its decay products was 1.75 mSv·a-1 in HBRA.We noted that Rn-220 and its decay products are very important component of effective dose for the inhabitants living in the HBRA.
  • Comparison of GVHD in Different Sorts of Bone Marrow Transplantation
    LIU Chuan-fang, PENG Jun, ZHANG Yu-kun, et al
    2002, 11(2): 69-70.
    Download PDF ( ) HTML   Knowledge map   Save
    Objective To study GVHD in different sorts of BMT.Methods C57BL/6 recipient mice irradiated with 60Co were transfused with donor cells via the tail vein.The general manifestation and pathological changes of GVHD were observed.The hematopoietic function was evaluated with the spleen node count under microscope, semi-solid agar CFU-GM assay and peripheral blood WBC count.The C banding technique was used to detect the chimeric rate in different sorts of BMT.Results The survival rate on day 30 in syngeneic group or mixed half-matched group was higher than two other groups.The GVHD reaction was strong in allogeneic group, to a less extent in half-matched group, and the least in mixed half-matched group.Spleen node count on day 13 showed no significant difference between the syngeneic and the mixed half-matched group although both groups had larger numbers than the allogeneic or the half-matched group.The chimeric rate in mixed half-matched group was not different from the half-matched group on day 18, while it was higher in the mixed half-matched group on day 30.The extent of mixed lymphocyte reaction in vivo was in descending sequence in allogeneic, half-matched, mixed half-matched and syngeneic BMT group.The peripheral blood WBC count and bone marrow CFU-GM assay showed no significant difference among other groups except that they are lower in the allogeneic group.Conclusion Half-matched and mixed half-matched BMT could alleviate the GVHD reaction.
  • Radiological Monitoring and Assessment for Gamma Stereotactic Body Radiotherapy Equipment
    XIE Xiang-dong, YANG Guo-shan, ZHOU Hong-mei, et al
    2002, 11(2): 71-72.
    Download PDF ( ) HTML   Knowledge map   Save
    Objective To establish the radiological monitoring items and assessment principle for gamma stereotactic body radiotherapy equipment.Methods According to the radiological health protection standard on gamma-beam teletherapy equipment in medicine and relevant standards, combined with the characteristic of the gamma stereotactic body radiotherapy equipment and the radiological checkout experience, analysis and summing-up are made.Results A set of the items, methodology and assessment principle for radiological monitoring of gamma stereotactic body radiotherapy equipment are established.Conclusion The established methodology and assessment principle can be a supplement to radiological health protection standard on gamma-beam teletherapy equipment in medicine, and can be used for radiological monitoring and assessment for the gamma stereotactic body radiotherapy equipment.
  • Phantom Scattering Correction Coefficient of 60Co Rays Calculated by Sievert Method Combined with Experimental Method
    XU Zhi-yong, ZHANG Liang-an, DAI Guang-fu, et al
    2002, 11(2): 73-74.
    Download PDF ( ) HTML   Knowledge map   Save
    Objective Scattering correction coefficient of 60Co rays equivalent phantom was calculated by Sievert calculational method combined with experimental data.Methods Absorbed doses were measured by TLD experimental methods and scattering correction coefficients were fitted by Matlab application computer program.Results Scattering correction coefficient of equivalent phantom was given.Absorbed doses of two simulating accidents and relative variance of absorbed dose measured by TLD method and by Sievert method were calculated.Conclusion The discrepancy of absorbed dose between measured data and calculated data is small and the illuminated results fitted the correction coefficient is applicable in the regional scope.
  • Preliminary Study on the Regulatory Limits of Radiological Protection for Minerals Associated with Radionuclides
    LIU Ming, JI Cheng-fu, ZHAO Fu-xiang, et al
    2002, 11(2): 75-77.
    Download PDF ( ) HTML   Knowledge map   Save
    Objective To study and establish the regulatory Limits of radiological protection for minerals associated with radionuclides.Methods To deduce the limits according to the international and domestic references in combination with china's practices.Results The regulatory Limits of radiological protection for minerals associated with radionuclides have been suggested.Conclusion It is necessary and practical to establish the limits which are of great importance to the health of the public as well as the worker's.
  • Study of the Effect of 131I Treatment of Graves Disease on the Number of Peripheral Blood Leucocyte
    WANG Jin-biao, LIU Jun-qing, MA Yu-qin, et al
    2002, 11(2): 78-79.
    Download PDF ( ) HTML   Knowledge map   Save
    Objective To study the effect of 131I treatment of Graves disease on the number of peripheral blood leucocytes.Methods The Graves disease patients were divided into groups according to the 131I dosage taken, peripheral blood leucocytes were measured before and after the taking of 131I.Results On the 4th day after taking 131I, the absolute value of leucocyte, neutrophil, Lymphocyte were decreased, the number of neutrophil was significantly decreased (P <0.05 or P <0.01), the number of neutrophil had significant negative relationship with the dosage of 131I (P <0.05).The rate of patients whose leucocytes decreased were 69.4%.The number of leucocytes were close to primary level on the 7th day after taking 131I.Conclusion 131I treatment of Graves disease can reduce the number of leucoctes, especially neutrophil, in a short time (about one week), it is related with the dosage of 131I.After a week, they can nearly return to the primary level.Some medicine which can increase the number of leucocytes should be used when the patient taking 131I.