Background：Perineural invasion （PNI） is a histopathological characteristic of pancreatic cancer （PanCa）.The aim of this study was to observe the treatment effect of continuous low-dose-rate （CLDR） irradiation t...Background：Perineural invasion （PNI） is a histopathological characteristic of pancreatic cancer （PanCa）.The aim of this study was to observe the treatment effect of continuous low-dose-rate （CLDR） irradiation to PNI and assess the PNI-related pain relief caused by iodine-125 （125I） seed implantation.Methods：The in vitro PNI model established by co-culture with dorsal root ganglion （DRG） and cancer cells was interfered under 2 and 4 Gy of 125I seeds CLDR irradiation.The orthotopic models of PNI were established,and 125I seeds were implanted in tumor.The PNI-related molecules were analyzed.In 30 patients with panCa,the pain relief was assessed using a visual analog scale （VAS）.Pain intensity was measured before and 1 week,2 weeks,and 1,3,and 6 months after 125I seed implantation.Results：The co-culture of DRG and PanCa cells could promote the growth of PanCa cells and DRG neurites.In co-culture groups,the increased number of DRG neurites and pancreatic cells in radiation group was significantly less.In orthotopic models,the PNI-positive rate in radiation and control group was 3/11 and 7/11;meanwhile,the degrees of PNI between radiation and control groups was significant difference （P 〈 0.05）.At week 2,the mean VAS pain score in patients decreased by 50% and significantly improved than the score at baseline （P 〈 0.05）.The pain scores were lower in all patients,and the pain-relieving effect was retained about 3 months.Conclusions：The CLDR irradiation could inhibit PNI of PanCa with the value of further study.The CLDR irradiation could do great favor in preventing local recurrence and alleviating pain.展开更多
AIM: Tumor response and normal tissue toxicity of seven-day-per-week continuous accelerated irradiation (CAIR) for patients with esophageal carcinoma were evaluated and compared to conventional irradiation (CR). METHO...AIM: Tumor response and normal tissue toxicity of seven-day-per-week continuous accelerated irradiation (CAIR) for patients with esophageal carcinoma were evaluated and compared to conventional irradiation (CR). METHODS: Sixty patients with squamous cell carcinoma of the esophagus were randomized into two groups: the CAIR group (30 patients) and the CR group (30 pa- tients). Patients in the CAIR group received radiotherapy (RT) with 2 Gy/fraction per day at 7 d/wk with a total dose of 50-70 Gy (average dose 64.2 Gy). The overall time of irradiation was 3.6-5.0 wk (average 4.6 wk). RT in the CR group was 2 Gy/fraction per day at 5 d/wk with a total dose of 40-70 Gy (average dose 61.7 Gy). The overall time of irradiation was 4.0-7.0 wk (average 6.4 wk). RESULTS: The data showed that the immediate tumor response to RT was better in the CAIR group than in the CR group. Efficiency rates (CR plus PR) were 82.8% (24/29) and 58.6% (17/29), respectively (P = 0.047). In both groups the incidences of esophagitis and tracheitis were insignificant (P = 0.376, 0.959), and no patient re- ceived toxicity that could not be tolerated. CONCLUSION: CAIR shortens overall treatment time and is well tolerated by patients. It may be superior to CR in enhancing the local response of tumor, but its remote effect for esophageal carcinoma awaits further follow-up.展开更多
To calculate the radioactivity of product nuclides generated in pulse irradiation, it is generally assumed that the irradiation is approximately continuous in the entire irradiation period(ti) and the flux of the inco...To calculate the radioactivity of product nuclides generated in pulse irradiation, it is generally assumed that the irradiation is approximately continuous in the entire irradiation period(ti) and the flux of the incoming irradiation particle can be obtained by averaging their intensity in each pulse period(T). However, this approximation fails to acknowledge the fact that the product nuclides are not created in each pulse period(T)evenly: They are only produced in a very short pulse width(tp) and then decay in a relatively long rest time(tr = T-tp). Given by the enormous number of pulses, the sum of these decays may not be negligible. To make the activity calculation in accordance with the real situation in pulse irradiation, we scrutinize the details of irradiation and decay processes in each pulse, apply the geometric series to obtain the activity superimposition of millions of pulses,and derive a novel activity equation particularly suitable for pulse irradiation. The experimental results,numerical simulations,and activity measurements from photon activation driven by a pulsed electron LINAC have confirmed the validity of this new equation. The comparison between the new and traditional equations indicates that their discrepancy could be significant under certain conditions. The limitations of the new activity equation for pulse irradiation are discussed as well.展开更多
基金This study was supported by the grants from the Beijing Municipal Science and Technology Commission （No. Z141107002514184）, the National Natural Science Foundation of China （No. 81272667）, and the Beijing Municipal Science and Technology Commission （No. Z151100004015213）.
文摘Background：Perineural invasion （PNI） is a histopathological characteristic of pancreatic cancer （PanCa）.The aim of this study was to observe the treatment effect of continuous low-dose-rate （CLDR） irradiation to PNI and assess the PNI-related pain relief caused by iodine-125 （125I） seed implantation.Methods：The in vitro PNI model established by co-culture with dorsal root ganglion （DRG） and cancer cells was interfered under 2 and 4 Gy of 125I seeds CLDR irradiation.The orthotopic models of PNI were established,and 125I seeds were implanted in tumor.The PNI-related molecules were analyzed.In 30 patients with panCa,the pain relief was assessed using a visual analog scale （VAS）.Pain intensity was measured before and 1 week,2 weeks,and 1,3,and 6 months after 125I seed implantation.Results：The co-culture of DRG and PanCa cells could promote the growth of PanCa cells and DRG neurites.In co-culture groups,the increased number of DRG neurites and pancreatic cells in radiation group was significantly less.In orthotopic models,the PNI-positive rate in radiation and control group was 3/11 and 7/11;meanwhile,the degrees of PNI between radiation and control groups was significant difference （P 〈 0.05）.At week 2,the mean VAS pain score in patients decreased by 50% and significantly improved than the score at baseline （P 〈 0.05）.The pain scores were lower in all patients,and the pain-relieving effect was retained about 3 months.Conclusions：The CLDR irradiation could inhibit PNI of PanCa with the value of further study.The CLDR irradiation could do great favor in preventing local recurrence and alleviating pain.
基金Supported by the Xuzhou Science and Technology Office, No. X2003024
文摘AIM: Tumor response and normal tissue toxicity of seven-day-per-week continuous accelerated irradiation (CAIR) for patients with esophageal carcinoma were evaluated and compared to conventional irradiation (CR). METHODS: Sixty patients with squamous cell carcinoma of the esophagus were randomized into two groups: the CAIR group (30 patients) and the CR group (30 pa- tients). Patients in the CAIR group received radiotherapy (RT) with 2 Gy/fraction per day at 7 d/wk with a total dose of 50-70 Gy (average dose 64.2 Gy). The overall time of irradiation was 3.6-5.0 wk (average 4.6 wk). RT in the CR group was 2 Gy/fraction per day at 5 d/wk with a total dose of 40-70 Gy (average dose 61.7 Gy). The overall time of irradiation was 4.0-7.0 wk (average 6.4 wk). RESULTS: The data showed that the immediate tumor response to RT was better in the CAIR group than in the CR group. Efficiency rates (CR plus PR) were 82.8% (24/29) and 58.6% (17/29), respectively (P = 0.047). In both groups the incidences of esophagitis and tracheitis were insignificant (P = 0.376, 0.959), and no patient re- ceived toxicity that could not be tolerated. CONCLUSION: CAIR shortens overall treatment time and is well tolerated by patients. It may be superior to CR in enhancing the local response of tumor, but its remote effect for esophageal carcinoma awaits further follow-up.
基金supported by the U.S.Department of Energy,Office of Environmental Management(EM),MSIPP program under TOA#0000272361
文摘To calculate the radioactivity of product nuclides generated in pulse irradiation, it is generally assumed that the irradiation is approximately continuous in the entire irradiation period(ti) and the flux of the incoming irradiation particle can be obtained by averaging their intensity in each pulse period(T). However, this approximation fails to acknowledge the fact that the product nuclides are not created in each pulse period(T)evenly: They are only produced in a very short pulse width(tp) and then decay in a relatively long rest time(tr = T-tp). Given by the enormous number of pulses, the sum of these decays may not be negligible. To make the activity calculation in accordance with the real situation in pulse irradiation, we scrutinize the details of irradiation and decay processes in each pulse, apply the geometric series to obtain the activity superimposition of millions of pulses,and derive a novel activity equation particularly suitable for pulse irradiation. The experimental results,numerical simulations,and activity measurements from photon activation driven by a pulsed electron LINAC have confirmed the validity of this new equation. The comparison between the new and traditional equations indicates that their discrepancy could be significant under certain conditions. The limitations of the new activity equation for pulse irradiation are discussed as well.
