Objective Radiotherapy combined with conservative surgery plays an important role in the treatment of early-stage breast cancer. Volumetric modulated arc therapy(VMAT) has been introduced into clinical practice. The p...Objective Radiotherapy combined with conservative surgery plays an important role in the treatment of early-stage breast cancer. Volumetric modulated arc therapy(VMAT) has been introduced into clinical practice. The purpose of this study was to investigate the dosimetric effects of different multileaf collimators(MLC) on VMAT radiotherapy plans for treating breast cancer.Methods Fifteen breast cancer patients who were treated using a conventional technique in our department were selected to participate in this retrospective analysis. VMAT plans based on three types of Elekta MLCs [Beam Modulator(BM) with 4-mm leaf width, Agility with 5-mm leaf width and MLCi2 with 10-mm leaf width] were independently generated for each patient. Plan comparisons were performed based on dose-volume histogram(DVH) analysis including dosimetric parameters such as the homogeneity index(HI), conformity index(CI), Dmax, Dmin, and Dmean for the planning treatment volume(PTV), in addition to dose-volume parameters for the organs at risk(OARs). The delivery efficiency of the three types of MLCs was compared in terms of the beam delivery time and the monitor units(MUs) per fraction for each plan. Results Both target uniformity and conformity were improved in plans for Agility and BM MLC compared with the plan using MLCi2. The mean HI decreased from 1.14 for MLCi2 to 1.13 for BM and 1.10 for Agility, while the mean CI increased from 0.68 for MLCi2 to 0.73 for BM and 0.75 for Agility. Furthermore, at both low and high dose levels, smaller volumes of ipsilateral lung, heart, contralateral lung, and breast were irradiated with Agility MLC than with the other two types of MLCs. The delivery time with Agility MLC was reduced by 10.8% and 32.1%, respectively, compared with that for MLCi2 and BM.Conclusion Our results indicate that the Agility MLC exhibits a dosimetric advantage and a significant improvement in delivery efficiency for the treatment of breast cancer using VMAT.展开更多
Objective: To summarize the experience of the treatment of traumatic hepatorrhexis. Methods: The clinical data of 209 cases of liver trauma treated in the three affiliated hospitals of the Third Military Medical Unive...Objective: To summarize the experience of the treatment of traumatic hepatorrhexis. Methods: The clinical data of 209 cases of liver trauma treated in the three affiliated hospitals of the Third Military Medical University from 1989 to 1999 were retrospectively analyzed. Among the 209 patients, 108 ( 51.7 %) had Grade III or more severe liver injury. Operative treatment was performed in 186 cases and preservative treatment in 23. Results: In the operated group, 169 patients were cured. The complications occurred in 18 patients and 17 of them died. In the non operated group, the complications occurred in 22 patients and only 1 of them died. Conclusions: Severe injury and delayed treatment are two major factors leading to death from liver injuries. Surgical intervention is still the principal measure to treat traumatic hepatorrhexis. The indications for non operative treatment should be carefully selected.展开更多
文摘Objective Radiotherapy combined with conservative surgery plays an important role in the treatment of early-stage breast cancer. Volumetric modulated arc therapy(VMAT) has been introduced into clinical practice. The purpose of this study was to investigate the dosimetric effects of different multileaf collimators(MLC) on VMAT radiotherapy plans for treating breast cancer.Methods Fifteen breast cancer patients who were treated using a conventional technique in our department were selected to participate in this retrospective analysis. VMAT plans based on three types of Elekta MLCs [Beam Modulator(BM) with 4-mm leaf width, Agility with 5-mm leaf width and MLCi2 with 10-mm leaf width] were independently generated for each patient. Plan comparisons were performed based on dose-volume histogram(DVH) analysis including dosimetric parameters such as the homogeneity index(HI), conformity index(CI), Dmax, Dmin, and Dmean for the planning treatment volume(PTV), in addition to dose-volume parameters for the organs at risk(OARs). The delivery efficiency of the three types of MLCs was compared in terms of the beam delivery time and the monitor units(MUs) per fraction for each plan. Results Both target uniformity and conformity were improved in plans for Agility and BM MLC compared with the plan using MLCi2. The mean HI decreased from 1.14 for MLCi2 to 1.13 for BM and 1.10 for Agility, while the mean CI increased from 0.68 for MLCi2 to 0.73 for BM and 0.75 for Agility. Furthermore, at both low and high dose levels, smaller volumes of ipsilateral lung, heart, contralateral lung, and breast were irradiated with Agility MLC than with the other two types of MLCs. The delivery time with Agility MLC was reduced by 10.8% and 32.1%, respectively, compared with that for MLCi2 and BM.Conclusion Our results indicate that the Agility MLC exhibits a dosimetric advantage and a significant improvement in delivery efficiency for the treatment of breast cancer using VMAT.
文摘Objective: To summarize the experience of the treatment of traumatic hepatorrhexis. Methods: The clinical data of 209 cases of liver trauma treated in the three affiliated hospitals of the Third Military Medical University from 1989 to 1999 were retrospectively analyzed. Among the 209 patients, 108 ( 51.7 %) had Grade III or more severe liver injury. Operative treatment was performed in 186 cases and preservative treatment in 23. Results: In the operated group, 169 patients were cured. The complications occurred in 18 patients and 17 of them died. In the non operated group, the complications occurred in 22 patients and only 1 of them died. Conclusions: Severe injury and delayed treatment are two major factors leading to death from liver injuries. Surgical intervention is still the principal measure to treat traumatic hepatorrhexis. The indications for non operative treatment should be carefully selected.
