In this study, a novel phoswich detector for beta–gamma coincidence detection is designed. Unlike the triple crystal phoswich detector designed by researchers at the University of Missouri, Columbia, this phoswich de...In this study, a novel phoswich detector for beta–gamma coincidence detection is designed. Unlike the triple crystal phoswich detector designed by researchers at the University of Missouri, Columbia, this phoswich detector is of the semi-well type, so it has a higher detection efficiency. The detector consists of BC-400 and NaI:Tl with decay time constants of 2.4 and 230 ns, respectively.The BC-400 scintillator detects beta particles, and the Na I:Tl cell is used for gamma detection. Geant4 simulations of this phoswich detector find that a 2-mm-thick BC-400 scintillator can absorb nearly all of the beta particles whose energies are below 700 keV. Further, for a 2.00-cmthick NaI:Tl crystal, the gamma source peak efficiency for photons ranges from a maximum of nearly 90% at 30 keV to 10% at 1 MeV. The self-absorption effect is also discussed in this paper in order to determine the carrier gas' s influence.展开更多
In Wireless Body Area Networks(WBANs)with respect to health care,sensors are positioned inside the body of an individual to transfer sensed data to a central station periodically.The great challenges posed to healthca...In Wireless Body Area Networks(WBANs)with respect to health care,sensors are positioned inside the body of an individual to transfer sensed data to a central station periodically.The great challenges posed to healthcare WBANs are the black hole and sink hole attacks.Data from deployed sensor nodes are attracted by sink hole or black hole nodes while grabbing the shortest path.Identifying this issue is quite a challenging task as a small variation in medicine intake may result in a severe illness.This work proposes a hybrid detection framework for attacks by applying a Proportional Coinciding Score(PCS)and an MK-Means algorithm,which is a well-known machine learning technique used to raise attack detection accuracy and decrease computational difficulties while giving treatments for heartache and respiratory issues.First,the gathered training data feature count is reduced through data pre-processing in the PCS.Second,the pre-processed features are sent to the MK-Means algorithm for training the data and promoting classification.Third,certain attack detection measures given by the intrusion detection system,such as the number of data packages trans-received,are identified by the MK-Means algorithm.This study demonstrates that the MK-Means framework yields a high detection accuracy with a low packet loss rate,low communication overhead,and reduced end-to-end delay in the network and improves the accuracy of biomedical data.展开更多
Positron emission tomography （PET） using 18F-fluorodeoxyglucose （FDG） has not been widely used in China for expensive cost （$1200）. Dual-head coincidence single photon emission computed tomography （DHC-SPECT） ...Positron emission tomography （PET） using 18F-fluorodeoxyglucose （FDG） has not been widely used in China for expensive cost （$1200）. Dual-head coincidence single photon emission computed tomography （DHC-SPECT） can depict many of the lesions depicted with a PET scanner in the lungs, which is used in place of PET-CT for discriminating malignant from benign pulmonary nodules in many studies. However, DHC-SPECT has inevitable false-negative results because the sensitivity for small lesions less than 2.0 cm is limited, and has high false-positive rate for active inflammatory nodules. Furthermore,DHC-SPECT also has a considerably higher cost （$300 in China） than other imaging examination.展开更多
背景与目的:葡萄糖肿瘤代谢显像已广泛应用于临床,而双时相显像技术能够更真实地反映肿瘤的葡萄糖代谢情况,更有助于良恶性的鉴别。探讨双时相^(18)F-FDG符合线路SPECT/CT显像在肺占位性病变鉴别诊断中的应用价值。方法:胸部CT检查发现...背景与目的:葡萄糖肿瘤代谢显像已广泛应用于临床,而双时相显像技术能够更真实地反映肿瘤的葡萄糖代谢情况,更有助于良恶性的鉴别。探讨双时相^(18)F-FDG符合线路SPECT/CT显像在肺占位性病变鉴别诊断中的应用价值。方法:胸部CT检查发现肺占位性病变患者28例。被检查者注射显像剂40~60 min后行胸部早期符合线路SPECT/CT显像,延迟显像于静脉注射显像剂后2~3 h进行。计算早期及延时两次显像病灶部位(T)与正常部位(N)的放射性计数比值T1/N1及T2/N2,并计算T/N的变化率ΔT/N。利用受试者工作特征曲线(receiver operating characteristic curve,ROC)确定T1/N1、T2/N2及ΔT/N的诊断阈值,应用曲线下面积(area under the curve,AUC)分别评价早期显像和双时相显像的诊断效能。结果:早期显像T1/N1的诊断阈值为2.650,AUC为0.767,诊断肺癌的灵敏度为83.3%,特异度为30.0%,准确度为64.3%。延时显像T2/N2的诊断阈值为3.140,AUC为0.847,诊断肺癌的灵敏度为94.4%,特异度为60.0%,准确度为82.1%。ΔT/N的诊断阈值为16.9%,AUC为0.950,诊断肺癌的灵敏度为88.5%,特异度为71.4%,准确度为86.2%。结论:双时相^(18)F-FDG符合线路SPECT/CT显像对肺占位性病变的鉴别诊断与常规一次显像相比有较高的准确度和特异度,但仍存在假阳性,应结合患者CT图像特征及临床病史综合分析。展开更多
基金supported by the National Natural Science Foundation of China(Nos.11205108,11475121,and 11575145)the Excellent Youth Fund of Sichuan University(No.2016SCU04A13)
文摘In this study, a novel phoswich detector for beta–gamma coincidence detection is designed. Unlike the triple crystal phoswich detector designed by researchers at the University of Missouri, Columbia, this phoswich detector is of the semi-well type, so it has a higher detection efficiency. The detector consists of BC-400 and NaI:Tl with decay time constants of 2.4 and 230 ns, respectively.The BC-400 scintillator detects beta particles, and the Na I:Tl cell is used for gamma detection. Geant4 simulations of this phoswich detector find that a 2-mm-thick BC-400 scintillator can absorb nearly all of the beta particles whose energies are below 700 keV. Further, for a 2.00-cmthick NaI:Tl crystal, the gamma source peak efficiency for photons ranges from a maximum of nearly 90% at 30 keV to 10% at 1 MeV. The self-absorption effect is also discussed in this paper in order to determine the carrier gas' s influence.
基金funded by Stefan cel Mare University of Suceava,Romania.
文摘In Wireless Body Area Networks(WBANs)with respect to health care,sensors are positioned inside the body of an individual to transfer sensed data to a central station periodically.The great challenges posed to healthcare WBANs are the black hole and sink hole attacks.Data from deployed sensor nodes are attracted by sink hole or black hole nodes while grabbing the shortest path.Identifying this issue is quite a challenging task as a small variation in medicine intake may result in a severe illness.This work proposes a hybrid detection framework for attacks by applying a Proportional Coinciding Score(PCS)and an MK-Means algorithm,which is a well-known machine learning technique used to raise attack detection accuracy and decrease computational difficulties while giving treatments for heartache and respiratory issues.First,the gathered training data feature count is reduced through data pre-processing in the PCS.Second,the pre-processed features are sent to the MK-Means algorithm for training the data and promoting classification.Third,certain attack detection measures given by the intrusion detection system,such as the number of data packages trans-received,are identified by the MK-Means algorithm.This study demonstrates that the MK-Means framework yields a high detection accuracy with a low packet loss rate,low communication overhead,and reduced end-to-end delay in the network and improves the accuracy of biomedical data.
文摘Positron emission tomography （PET） using 18F-fluorodeoxyglucose （FDG） has not been widely used in China for expensive cost （$1200）. Dual-head coincidence single photon emission computed tomography （DHC-SPECT） can depict many of the lesions depicted with a PET scanner in the lungs, which is used in place of PET-CT for discriminating malignant from benign pulmonary nodules in many studies. However, DHC-SPECT has inevitable false-negative results because the sensitivity for small lesions less than 2.0 cm is limited, and has high false-positive rate for active inflammatory nodules. Furthermore,DHC-SPECT also has a considerably higher cost （$300 in China） than other imaging examination.
文摘背景与目的:葡萄糖肿瘤代谢显像已广泛应用于临床,而双时相显像技术能够更真实地反映肿瘤的葡萄糖代谢情况,更有助于良恶性的鉴别。探讨双时相^(18)F-FDG符合线路SPECT/CT显像在肺占位性病变鉴别诊断中的应用价值。方法:胸部CT检查发现肺占位性病变患者28例。被检查者注射显像剂40~60 min后行胸部早期符合线路SPECT/CT显像,延迟显像于静脉注射显像剂后2~3 h进行。计算早期及延时两次显像病灶部位(T)与正常部位(N)的放射性计数比值T1/N1及T2/N2,并计算T/N的变化率ΔT/N。利用受试者工作特征曲线(receiver operating characteristic curve,ROC)确定T1/N1、T2/N2及ΔT/N的诊断阈值,应用曲线下面积(area under the curve,AUC)分别评价早期显像和双时相显像的诊断效能。结果:早期显像T1/N1的诊断阈值为2.650,AUC为0.767,诊断肺癌的灵敏度为83.3%,特异度为30.0%,准确度为64.3%。延时显像T2/N2的诊断阈值为3.140,AUC为0.847,诊断肺癌的灵敏度为94.4%,特异度为60.0%,准确度为82.1%。ΔT/N的诊断阈值为16.9%,AUC为0.950,诊断肺癌的灵敏度为88.5%,特异度为71.4%,准确度为86.2%。结论:双时相^(18)F-FDG符合线路SPECT/CT显像对肺占位性病变的鉴别诊断与常规一次显像相比有较高的准确度和特异度,但仍存在假阳性,应结合患者CT图像特征及临床病史综合分析。
