For radiation protection purposes, the neutron dose in carbon ion radiation therapy at the HIRFL （Heavy Ion Research Facility in Lanzhou） was investigated. The neutron dose from primary ^12C ions with a specific ene...For radiation protection purposes, the neutron dose in carbon ion radiation therapy at the HIRFL （Heavy Ion Research Facility in Lanzhou） was investigated. The neutron dose from primary ^12C ions with a specific energy of 100 MeV/u delivered from SSC was roughly measured with a standard Anderson-Broun rem-meter using a polyethylene target at various distances. The result shows that a maximum neutron dose contribution of 19 mSv in a typically surface tumor treatment was obtained, which is less than 1% of the planed heavy ion dose and is in reasonable agreement with other reports. Also the T-ray dose was measured in this experiment using a thermo luminescent detector.展开更多
The clinical trials of tumor therapy using heavy ions beam 12C are now in progress at Institute of Modern Physics in Lanzhou. In order to achieve the precise radiotherapy with the high energy 12C beam in active pencil...The clinical trials of tumor therapy using heavy ions beam 12C are now in progress at Institute of Modern Physics in Lanzhou. In order to achieve the precise radiotherapy with the high energy 12C beam in active pencil beam scanning mode, we have developed an ionization chamber(IC) as an online monitor for beam intensity and also a dosimeter after calibration. Through the choosing of working gas and voltage, optimizing of the electrics and the read-out system, calibrating the linearity, the detector system provide us one of the simple and highly reliable way to monitoring the beam during the active pencil beam scanning treatments. The measurement results of this detector system show that it could work well under the condition of high energy 12C beam in active pencil beam scanning mode.展开更多
Fluence rates and angular distributions of the neutron emitted by75 MeV/u 12C-ion bombardment on thick Be and An targets have been measured bymeans of the threshold detector activation method. Based on that, the neutr...Fluence rates and angular distributions of the neutron emitted by75 MeV/u 12C-ion bombardment on thick Be and An targets have been measured bymeans of the threshold detector activation method. Based on that, the neutron yields,emission rates in the forward direction and neutron dose equivalent rate distributionswere deduced.展开更多
In this work, the neutron radiation field at Heavy Ion Research Facility in Lanzhou （HIRFL） was investigated. Total neutron yields, spectra and angular distributions in the bombardment of various thick targets by 12...In this work, the neutron radiation field at Heavy Ion Research Facility in Lanzhou （HIRFL） was investigated. Total neutron yields, spectra and angular distributions in the bombardment of various thick targets by 12C and ^18O ions with energies up to 75 MeV/u were obtained using the activation method. The neutron dose equivalent rates of 60 MeV/u ^18O on various thick targets at different angles were measured with a modified A-B remmeter. Our results are compared with those of other reports.展开更多
The combination of ionizing radiation and gene therapy has been investigated. However, there are very few reports about the combination of heavy-ion irradiation and gene therapy. To determine if the pre-exposure to lo...The combination of ionizing radiation and gene therapy has been investigated. However, there are very few reports about the combination of heavy-ion irradiation and gene therapy. To determine if the pre-exposure to low-dose heavy ion beam enhances the suppression of AdCMV-p53 on non-small lung cancer (NSLC), the cells pre-irradiated or non-irradiated were infected with 20, 40 MOI of AdCMV-p53. Survival fraction and the relative biology effect (RBE) were determined by clonogenic assay. The results showed that the proportions of p53 positive cells in 12C6+ beam induced AdCMV-p53 infected cells were more than 90%, which were signifi-cantly more than those in γ-ray induced AdCMV-p53 infected cells. The pre-exposure to low-dose 12C6+ beam significantly prevented the G0/G1 arrest and activated G2/M checkpoints. The pre-exposure to 12C6+ beam significantly improved cell to apoptosis. RBEs for the 12C6+ + AdCMV-p53 infection groups were 30%-60%, 20%-130% and 30%-70% more than those for the 12C6+-irradiated only, AdCMV-p53 infected only, and γ-irradiation induced AdCMVp53 infected groups, respectively. The data suggested that the pre-exposure to low-dose 12C6+ beam significantly promotes exogenous p53 expression in NSLC, and the suppression of AdCMV-p53 gene therapy on NSLC.展开更多
以3.9×10^(11)离子/s·100 MeV/u^(12)C 离子轰击厚 Cu 靶的重离子反应为例,计算了用单一混凝土、Fe 作为局部屏蔽材料和用不同厚度的 Fe 加混凝土作局部屏蔽时中子剂量当量率的变化,确定了达到2.5×10^(-2)mSv/h 中子剂...以3.9×10^(11)离子/s·100 MeV/u^(12)C 离子轰击厚 Cu 靶的重离子反应为例,计算了用单一混凝土、Fe 作为局部屏蔽材料和用不同厚度的 Fe 加混凝土作局部屏蔽时中子剂量当量率的变化,确定了达到2.5×10^(-2)mSv/h 中子剂量当量率限值的屏蔽厚度。展开更多
设计了一种用于兰州重离子治癌系统中剂量监测的新型电荷-频率转换电路。该电路将输入的电流信号直接转换为脉冲输出,通过计数器对脉冲个数进行计数实现对输入电荷的测量,从而实现对照射剂量的实时监测。实验表明:该电路可实现0.01 n A^...设计了一种用于兰州重离子治癌系统中剂量监测的新型电荷-频率转换电路。该电路将输入的电流信号直接转换为脉冲输出,通过计数器对脉冲个数进行计数实现对输入电荷的测量,从而实现对照射剂量的实时监测。实验表明:该电路可实现0.01 n A^1μA范围内双极性电流的测量,在整个测量范围内线性度好于2.71%。展开更多
基金Supported by Foundation of Director of the Institute of Moderm Physics,Chinese Academy of Sciences,China
文摘For radiation protection purposes, the neutron dose in carbon ion radiation therapy at the HIRFL （Heavy Ion Research Facility in Lanzhou） was investigated. The neutron dose from primary ^12C ions with a specific energy of 100 MeV/u delivered from SSC was roughly measured with a standard Anderson-Broun rem-meter using a polyethylene target at various distances. The result shows that a maximum neutron dose contribution of 19 mSv in a typically surface tumor treatment was obtained, which is less than 1% of the planed heavy ion dose and is in reasonable agreement with other reports. Also the T-ray dose was measured in this experiment using a thermo luminescent detector.
基金Supported by the National Nature Science Foundation of China (No. 10305015, No.10475098)the Major Program of the Chinese Academy of Science (No. O701050YZD)
文摘The clinical trials of tumor therapy using heavy ions beam 12C are now in progress at Institute of Modern Physics in Lanzhou. In order to achieve the precise radiotherapy with the high energy 12C beam in active pencil beam scanning mode, we have developed an ionization chamber(IC) as an online monitor for beam intensity and also a dosimeter after calibration. Through the choosing of working gas and voltage, optimizing of the electrics and the read-out system, calibrating the linearity, the detector system provide us one of the simple and highly reliable way to monitoring the beam during the active pencil beam scanning treatments. The measurement results of this detector system show that it could work well under the condition of high energy 12C beam in active pencil beam scanning mode.
文摘Fluence rates and angular distributions of the neutron emitted by75 MeV/u 12C-ion bombardment on thick Be and An targets have been measured bymeans of the threshold detector activation method. Based on that, the neutron yields,emission rates in the forward direction and neutron dose equivalent rate distributionswere deduced.
文摘In this work, the neutron radiation field at Heavy Ion Research Facility in Lanzhou （HIRFL） was investigated. Total neutron yields, spectra and angular distributions in the bombardment of various thick targets by 12C and ^18O ions with energies up to 75 MeV/u were obtained using the activation method. The neutron dose equivalent rates of 60 MeV/u ^18O on various thick targets at different angles were measured with a modified A-B remmeter. Our results are compared with those of other reports.
文摘The combination of ionizing radiation and gene therapy has been investigated. However, there are very few reports about the combination of heavy-ion irradiation and gene therapy. To determine if the pre-exposure to low-dose heavy ion beam enhances the suppression of AdCMV-p53 on non-small lung cancer (NSLC), the cells pre-irradiated or non-irradiated were infected with 20, 40 MOI of AdCMV-p53. Survival fraction and the relative biology effect (RBE) were determined by clonogenic assay. The results showed that the proportions of p53 positive cells in 12C6+ beam induced AdCMV-p53 infected cells were more than 90%, which were signifi-cantly more than those in γ-ray induced AdCMV-p53 infected cells. The pre-exposure to low-dose 12C6+ beam significantly prevented the G0/G1 arrest and activated G2/M checkpoints. The pre-exposure to 12C6+ beam significantly improved cell to apoptosis. RBEs for the 12C6+ + AdCMV-p53 infection groups were 30%-60%, 20%-130% and 30%-70% more than those for the 12C6+-irradiated only, AdCMV-p53 infected only, and γ-irradiation induced AdCMVp53 infected groups, respectively. The data suggested that the pre-exposure to low-dose 12C6+ beam significantly promotes exogenous p53 expression in NSLC, and the suppression of AdCMV-p53 gene therapy on NSLC.
文摘设计了一种用于兰州重离子治癌系统中剂量监测的新型电荷-频率转换电路。该电路将输入的电流信号直接转换为脉冲输出,通过计数器对脉冲个数进行计数实现对输入电荷的测量,从而实现对照射剂量的实时监测。实验表明:该电路可实现0.01 n A^1μA范围内双极性电流的测量,在整个测量范围内线性度好于2.71%。
