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  • 28 September 2005 Volume 14 Issue 3
      
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  • Adaptive Response of Spermatogenic Cell Apoptosis and p53 Gene Expression Selectively Induced by Irradiation with Low Dose X-Ray in Mice
    LIU Guang-wei, GONG Ping-sheng, ZHAO Hong-guang, et al
    2005, 14(3): 161-164. https://doi.org/10.13491/j.cnki.issn.1004-714x.2005.03.001
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    Objective The adaptive response of spermatogenic cell apoptosis and p53 gene expression induced by whole-body low dose radiation (LDR) with X-rays was studied in male Kunming mice.Methods Different kinds of spermatogenic cells were separated using density gradient centrifugation and their apoptotic percentagcs were analysed using flow cytometry (FCM) stained with propodium iodide.At meantime,p53 protein was measured with immunohistochemical SABC.Results When inductive dose (D1) was 75 mGy 6 h before irradiation with the challenging doses (D2) of 1.0,2.0 or 3.0 Gy,the apoptotic percentages of the spermatogonia and spermatocytes in the D1+D2 groups were declined rapidly as compared with those in the D2 groups,and the apoptotic percentages of spermatids and spermatozoa showed no significant changes.When inductive dose (D1) was 75 mGy 6 h before irradiation with the challenging doses (D2) of 1.0,2.0 or 3.0 Gy,the percentages of p53 protein positive of spermatogonia and spermatocytes in the D1+D2 groups were declined rapidly as compared with those in the D2 groups,and the positive percentages of spermatids and spermatozoa showed no significant changes.Conclusion The adaptive response of apoptosis and p53 protein expression in spermatogonia and spermatocytes could be selectively induced by irradiation with low dose X-ray.The apoptotic adaptive response induced by LDR could closely relate to the D2 doses and interval time between D1 and D2,so we speculated that p53 gene plays a great role in molecular mechanisms of adaptive response on spermatogenic cell apoptosis induced by LDR.
  • Prediction of PET/CT to Alleviate Radiation Pneumonitis in Patients with Non-small Cell Lung Cancer for 3-dimentional Confo rmal Radiotherapy
    GONG He-yi, YU Jin-ming, LI Jian-bin, et al
    2005, 14(3): 164-166. https://doi.org/10.13491/j.cnki.issn.1004-714x.2005.03.002
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    Objective To investigate the impact of PET/CT on clinical staging of non-small cell lung cancer (NSCLC),delineation of target volume,and prediction to alleviate radiation pneumonitis (RP) from 3-dimentional conformal radiotherapy (3D-CRT) planning.Methods From October 2002 to June 2004,34 patients diagnosed cytologically or pathologically with NSCLC,who were candidates for radical radiotherapy or surgery,received PET/CT scanning.Both images were transmitted into treatment planning system (TPS) workstations respectively and were fused and reconstructed.All patients were staged according to the 1997 World Health Organization (WHO) staging system.The impact of PET/CT on the clinical staging of all the patients was determined.The gross tumor volume (GTV) was delineated on the CT imaging and PET/CT fused imaging respectively.Based on the two images,3D-CRT planning was made respectively at the TPS workstation with Topslane software,the planning target volumes (PTV) being defined with a 15 mm margin around GTV of primary lumps (PTV1) and 7 mm for involved lymph nodes (PTV2).Evaluating indexes including VPTV (volume of PTV,VPTV=VPTV1+VPTV2),V20(percentage of the total lung volume receiving more than 20 Gy),MLD (mean lung dose),TCP (tumor control probability),NTCP (normal tissue complication probability),and Ds (dose to spinal cord) were selected to be paralleled to compare the quality of the two plans and the impact of PET/CT on RP was further analyzed.Results In 13 of 34(38.2%) cases,PET/CT information changed the clinical staging,8 of which were upstaged and 5 downstaged.For 10 of 34(29.4%) cases,PET/CT results modified their management decisions.Among 16 patients performed by surgery,14 had consistent PET/CT staging with pathologic staging.The sensitivity of PET/CT was 93.3% and accuracy 87.5%.Difference of indexes including VPTV,V20 and MLD between the two radiation planning was statistically significant,but Ds,TCP and NTCP were not statistically different.Conclusion PET/CT has notable impact on clinical staging,target volume delineation and hence on its 3D-CRT planning of NSCLC.In contouring the target volume,compared with CT imaging,PET/CT can decrease VPTV,V20 and MLD significantly in patients with atelectasis and obstructive pneunonitis,so can reduce the rate and severity of RP effectively and can better protect normal lung tissues.
  • Study on 3D-Dose Distribution of 192Ir HDR Intracavitary Brachytherapy for Cervix Cancer Patients by TLD and Anthropomorphic Pelvic Phantom
    ZHANG Shu-xu, LI Wen-hua, XU Hai-rong, et al
    2005, 14(3): 167-169. https://doi.org/10.13491/j.cnki.issn.1004-714x.2005.03.003
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    Objective To investigate the feasibility of checking the 3D-dose distribution of 192Ir HDR intracavitary brachytherapy for cervix cancer patients by TLD and anthropomorphic pelvic phantom.Methods The heating program,the range of dose linear response,the reproducibility and the calibration factor of the TLD (JR1152-F,1 mm×1 mm×6 mm) were determined.The tissue equivalent pelvic phantom was cut into six segments and a set of small holes (φ1×6 mm) were drilled at the interesting organs on each segment to hold the TLDs.The lead markers (φ1×6 mm) were placed in the holes.After the tandem catheter had been put into the treatment position,the orthogonal X-films could be taken and the lead markers were replaced by the TLDs.An orthogonal radiography-based brachytherapy treatment planning was designed by microSelectron HDR treatment planning system (TPS) with the prescription dose to Point A of 200 cGy.The doses to each measuring position were calculated.After the treatment plan was delivered,the doses to each TLD were measured by dosimeter.Results The range of dose linear response of the TLD is within 300 cGy with correlation coefficient of 0.997.The average reproducibility is less than ±4.0%.The calculated and measured dose values are in good coincidence at Pont A,Point B,Point F,bladder and rectum reference points.The relative errors for those positions are within ±3.6%,±0.9%,±7.8%,±7.1% and 6.4%,respectively.Conclusion The JR1152-F TLD and the anthropomorphic pelvic phantom are accurate and reliable in checking the 3D-dose distribution of 192Ir HDR intracavitary brachytherapy for cervix cancer patients.
  • The Accuracy Assessment of PPS in Fixed Beam Proton Therapy: Isocentric Rotation Movement
    LI Xin-ping, ZENG Xian-wen, XU Wen-ling, et al
    2005, 14(3): 170-172. https://doi.org/10.13491/j.cnki.issn.1004-714x.2005.03.005
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    Objective To assess the accuracy of isocentric rotation movement of Patient Positioning System (PPS) in fixed beam proton therapy.Methods A 2mm-diameter radioopaque sphere was positioned above the couch and was aligned to room isocenter (ISO).11 PPS angles were selected to make isocentric rotation test respectively.The displacement of the sphere to ISO were measured and calculated by Digital Image Positioning System (DIPS) respectively when PPS reached each designed position.Totally four group measurements were repeated at different time.all data were collected and statistical analysis were performed.Results The maximum shifts are (0.29±0.05) mm,(0.21±0.04) mm and (-0.21±0.04) mm on X,Y,Z axes at -110° PPS position,the absolute displacement of the sphere to ISO is (0.41±0.07) mm (1SD).The minimum shifts are (-0.03±0.05) mm,(0.05±0.05) mm and (0.00±0.00) mm on three principle axes at 30° PPS position,the absolute displacement of the sphere to ISO is (0.05 ±0.06) mm.Conclusion The isocentric rotation movement is the linchpin to realize multi-angle isocentric irradiation in fixed beam proton therapy.It is a complicated combined movement including PPS rotation and PPS translations.Since the high demand in the of precision of patient positioning,the accuracy of this combined movement played important role in proton therapy.In our tests,all shifts are less than 0.5 mm,can reach the requirement of positioning accuracy in proton therapy.
  • Research on Monitoring Caesium-137 Radiation Level of Land Environment by Crustaceous Lichens
    DU Chun-guang, ZHANG Jing, LI Wen-hong, et al
    2005, 14(3): 172-173. https://doi.org/10.13491/j.cnki.issn.1004-714x.2005.03.006
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    Objective The activity of caesium-137(Bq/kg) in the crustaceous lichens and other samples were determined to testify the feasibility,of which crustaceous lichens worked as a sensitive biology monitor to record the caesium-137(Bq/kg) radiation level of land environment.Methods The measurements were performed by GEM series HPGe (high-purity Germanium) coaxial detector system (ADCAM-100) made by EC&G ORTEC Company in USA.Results It was found that the activity of caesium-137(Bq/kg) in the crustaceous lichens was one order of magnitude higher than that found in surface soil,and was over three orders of magnitude higher than those found in corn,vegetable,fruit,eggs,milk and meat.Conclusion The crustaceous lichens grow in most places,their growth period is long,and they adsorb the nutrition from the atmosphere by their surface,which prove crustaceous lichens may be one of the most sensitive biological monitors of caesium-137 remote transmission and environmental radiation level.
  • Cytogenetic Analysis and Radiation Effect Assessment of Exposed Individuals in a Lost Accident of 75Se Radiation Source
    CHEN Ying, SUN Ou-jun, LIU Xiu-lin
    2005, 14(3): 174-175. https://doi.org/10.13491/j.cnki.issn.1004-714x.2005.03.007
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    Objective To estimate radiation injury by cytogenetic analy sis for the exposed individuals in a Lost Accident of 75 Se Radiation Source.Methods Conventional chromosome aberration analysis and Cyt-B micronuclei test.Results The frequencies of dicentrics and rings in 38 subjects are significantly higher than spontaneous frequency,in which 2 subjects suffered from overexposure.Conclusion This incident belongs to an overexposed accident.
  • Protective Effect of Hong-Xue Tea Mixture Against Radiation Injury in Mice
    ZHAO Chun, ZHANG Xue-hui, WANG Qi
    2005, 14(3): 175-177. https://doi.org/10.13491/j.cnki.issn.1004-714x.2005.03.008
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    Objective To develop health food of anti-radition among biological source in Yunnan.Methods Screening test was done of the health food of biological source of anti-radiation injury in mice.It is indicated that Hong-Xue Tea Mixture among the biological source has the effect against radiation injury,observing experiment of dose-effect of Hong-Xue Tea Mixture was done.Micronuclei in the bone marrow polychromatophilic erythrocytes in each dose group of mice were examined,leucocytes number and 30 day survival rate of mice following whole-body 5.0 Gy γirradiation were also determined.Results Research showed that Hong-Xue Tea Mixture and Spirulina Platensis Mixture among the biological source have protective effect against radiation injury in mice.observing experiment of dose-effect of Hong-Xue Tea Mixture show that low,medium and high dose of Hong-Xue Tea Mixture can significantly decrease bone marrow PECMN rate of mice,increase leucocytes number and 30 day survival rate.Conclusion Hong-Xue Tea Mixture has potent protective effects against radiation injury in mice.
  • Study on Relationship between Mass and ESR Signal Intensity of Enamel
    JIAO Ling, ZHANG Wen-yi, PAN Zhi-hong, et al
    2005, 14(3): 177-178. https://doi.org/10.13491/j.cnki.issn.1004-714x.2005.03.009
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    Objective To study the relationship of different enamel sample mass and their enamel ESR signal intensities in order to find out a suitable mass range used in dose reconstruction.Methods The enamel samples are prepared from non-irradiated adult teeth by mechanical crash.The samples with different mass are scanned by an ESR spectrometer after their irradiation by 60Co γ rays.Results The linearity between ESR signal response and mass is not good in the range of 10~200 mg.But the linearity between ESR signal response and mass is good in the range of 40~120 mg.Conclusion It is better to choose enamel samples with the mass in the range of 40~120 mg in dose reconstruction.