There is increasing interest in the clinical use of flattening filter-free(FFF) beams.In this study,we aimed to investigate the dosimetric characteristics of volumetric modulated arc radiotherapy(VMAT) with FFF beams ...There is increasing interest in the clinical use of flattening filter-free(FFF) beams.In this study,we aimed to investigate the dosimetric characteristics of volumetric modulated arc radiotherapy(VMAT) with FFF beams for nasopharyngeal carcinoma(NPC).Ten NPC patients were randomly selected to undergo a RapidArc plan with either FFF beams(RA-FFF) or conventional beams(RA-C).The doses to the planning target volumes(PTVs),organs at risk(OARs),and normal tissues were compared.The technical delivery parameters for RapidArc plans were also assessed to compare the characteristics of FFF and conventional beams.Both techniques delivered adequate doses to PTVs.For PTVs,RA-C delivered lower maximum and mean doses and improved conformity and homogeneity compared with RA-FFF.Both techniques provided similar maximum doses to the optic nerves and lenses.For the brain stem,spinal cord,larynx,parotid glands,oral cavity,and skin,RA-FFF showed significant dose increases compared to RA-C.The dose to normal tissue was lower in RA-FFF.The monitor units(MUs) were(536 ± 46) MU for RA-FFF and(501± 25) MU for RA-C.The treatment duration did not significantly differbetween plans.Although both treatment plans could meet clinical needs,RA-C is dosimetrically superior to RA-FFF for NPC radiotherapy.展开更多
Bronchobiliary fistula(BBF) is one of the very rare disease.In this report,we described a BBF case.The case was diagnosed by endoscopic retrograde cholangio-pancreatography(ERCP) and percutaneous transhepatic cholangi...Bronchobiliary fistula(BBF) is one of the very rare disease.In this report,we described a BBF case.The case was diagnosed by endoscopic retrograde cholangio-pancreatography(ERCP) and percutaneous transhepatic cholangial drainage(PTCD) examinations,and treated properly.From the diagnosis of this BBF case,a patient with cough,biliptysis,fever and pain,should be considered for diagnosis of BBF.展开更多
We employ the static and dynamic copula models to investigate whether technical indicators provide information on volatility in the next trading day,where the volatility is measured by daily realized volatility.Our em...We employ the static and dynamic copula models to investigate whether technical indicators provide information on volatility in the next trading day,where the volatility is measured by daily realized volatility.Our empirical results,based on long samples of 8 well-known stock indexes,suggest that a significant and asymmetric tail dependence between the technical indicators based on moving average and the next day volatility.The level of dependence change over time in a persistent manner.And the dependence structure presents some distinct differences between emerging market indexes and developed market indexes.These results indicate that the technical indicators can provide information on the next day volatility at extremes,and are less informative at normal market.展开更多
文摘There is increasing interest in the clinical use of flattening filter-free(FFF) beams.In this study,we aimed to investigate the dosimetric characteristics of volumetric modulated arc radiotherapy(VMAT) with FFF beams for nasopharyngeal carcinoma(NPC).Ten NPC patients were randomly selected to undergo a RapidArc plan with either FFF beams(RA-FFF) or conventional beams(RA-C).The doses to the planning target volumes(PTVs),organs at risk(OARs),and normal tissues were compared.The technical delivery parameters for RapidArc plans were also assessed to compare the characteristics of FFF and conventional beams.Both techniques delivered adequate doses to PTVs.For PTVs,RA-C delivered lower maximum and mean doses and improved conformity and homogeneity compared with RA-FFF.Both techniques provided similar maximum doses to the optic nerves and lenses.For the brain stem,spinal cord,larynx,parotid glands,oral cavity,and skin,RA-FFF showed significant dose increases compared to RA-C.The dose to normal tissue was lower in RA-FFF.The monitor units(MUs) were(536 ± 46) MU for RA-FFF and(501± 25) MU for RA-C.The treatment duration did not significantly differbetween plans.Although both treatment plans could meet clinical needs,RA-C is dosimetrically superior to RA-FFF for NPC radiotherapy.
文摘Bronchobiliary fistula(BBF) is one of the very rare disease.In this report,we described a BBF case.The case was diagnosed by endoscopic retrograde cholangio-pancreatography(ERCP) and percutaneous transhepatic cholangial drainage(PTCD) examinations,and treated properly.From the diagnosis of this BBF case,a patient with cough,biliptysis,fever and pain,should be considered for diagnosis of BBF.
基金Supported by the Natural Science Foundation of Ningbo(2018A610130)National Statistical Science Research Program(2019LY71)+3 种基金MOE(Ministry of Education in China)Liberal Arts and Social Sciences FoundationNational Natural Science Foundation of China(11771399)Ningbo Soft Science Foundation(2017A10113)Fujian Education Department(JT180444).
文摘We employ the static and dynamic copula models to investigate whether technical indicators provide information on volatility in the next trading day,where the volatility is measured by daily realized volatility.Our empirical results,based on long samples of 8 well-known stock indexes,suggest that a significant and asymmetric tail dependence between the technical indicators based on moving average and the next day volatility.The level of dependence change over time in a persistent manner.And the dependence structure presents some distinct differences between emerging market indexes and developed market indexes.These results indicate that the technical indicators can provide information on the next day volatility at extremes,and are less informative at normal market.
