目的观察骨小梁分数(trabecular bone score,TBS)在成都地区人群中的分布及变化;评估TBS用于骨质疏松症治疗监测的精确度。方法选择2022年10月至2023年7月在四川省医学科学院·四川省人民医院就诊或体检者4963例,其中女性3708人,男...目的观察骨小梁分数(trabecular bone score,TBS)在成都地区人群中的分布及变化;评估TBS用于骨质疏松症治疗监测的精确度。方法选择2022年10月至2023年7月在四川省医学科学院·四川省人民医院就诊或体检者4963例,其中女性3708人,男性1255人,均行双能X线(DXA)检查测量腰椎TBS及骨密度(bone mineral density,BMD),结果以均值±标准差(SD)表示。选取30例患者每人行两次DXA检查,计算BMD、TBS的精确度误差。结果(1)TBS在男性20~29岁、女性30~39岁时达到峰值,之后均随增龄逐渐下降;(2)男、女TBS与年龄呈负相关,与体质量指数(body mass index,BMI)呈弱正相关;TBS与L1~4BMD呈正相关;(3)低骨量组男、女TBS受损者占比分别为19.6%、35.1%;BMD正常TBS受损+部分受损者占比分别为22.9%、40.5%。L_(1~4)BMD的CV%和LSC-CV%分别为1.089%、3.015%;TBS的CV%和LSC%分别为1.429%、3.958%。结论(1)本组TBS数据为成都地区人群骨质疏松防治、骨折风险评估提供了参考依据,随增龄BMD、TBS逐渐丢失,以女性更为明显;(2)TBS有较好的精确度,可用于骨质疏松症的治疗监测。展开更多
A new algorithm for iterative reconstruction is suggested.It is named simple self-correlative algebraic reconstruction technique (SSART).With numerical simulation experiments,SSART was applied in reconstructing a non-...A new algorithm for iterative reconstruction is suggested.It is named simple self-correlative algebraic reconstruction technique (SSART).With numerical simulation experiments,SSART was applied in reconstructing a non-ideal-bordered field in order to test its reconstructive effect.For contrast,three current representative algebraic reconstruction(ARTs) including basic ART,simultaneous ART (SART) and modified SART (MSART) were simulated simultaneously.The calculated results and reconstructive accuracy are discussed with three kinds of error indexes,namely mean-square error (MSE),absolute value error (AVE) and peak error (PE).As the results,the indexes of reconstructive accuracy are much improved by the proposed SSART.The MSE and PE have been decreased by 63.6% on the order of magnitude 10-4 and 88.9% on the order of magnitude 0-2,respectively,compared to that of ART.It is concluded that SSART is one of the most super iterative reconstructing techniques.展开更多
This paper investigates the mathematic features of non-linear models and discusses the processing way of non-linear factors which contributes to the non-linearity of a non-linear model. On the basis of the error defin...This paper investigates the mathematic features of non-linear models and discusses the processing way of non-linear factors which contributes to the non-linearity of a non-linear model. On the basis of the error definition,this paper puts forward a new adjustment criterion, SGPE.Last,this paper investigates the solution of a non-linear regression model in the non-linear model space and makes the comparison between the estimated values in non-linear model space and those in linear model space.展开更多
文摘目的观察骨小梁分数(trabecular bone score,TBS)在成都地区人群中的分布及变化;评估TBS用于骨质疏松症治疗监测的精确度。方法选择2022年10月至2023年7月在四川省医学科学院·四川省人民医院就诊或体检者4963例,其中女性3708人,男性1255人,均行双能X线(DXA)检查测量腰椎TBS及骨密度(bone mineral density,BMD),结果以均值±标准差(SD)表示。选取30例患者每人行两次DXA检查,计算BMD、TBS的精确度误差。结果(1)TBS在男性20~29岁、女性30~39岁时达到峰值,之后均随增龄逐渐下降;(2)男、女TBS与年龄呈负相关,与体质量指数(body mass index,BMI)呈弱正相关;TBS与L1~4BMD呈正相关;(3)低骨量组男、女TBS受损者占比分别为19.6%、35.1%;BMD正常TBS受损+部分受损者占比分别为22.9%、40.5%。L_(1~4)BMD的CV%和LSC-CV%分别为1.089%、3.015%;TBS的CV%和LSC%分别为1.429%、3.958%。结论(1)本组TBS数据为成都地区人群骨质疏松防治、骨折风险评估提供了参考依据,随增龄BMD、TBS逐渐丢失,以女性更为明显;(2)TBS有较好的精确度,可用于骨质疏松症的治疗监测。
基金This project was supported by China Postdoctoral Science Foun-dation(2004036121) the National Natural Science Foundation ofChina(10404022) Education Bureau of Shandong province(J04A63)
文摘A new algorithm for iterative reconstruction is suggested.It is named simple self-correlative algebraic reconstruction technique (SSART).With numerical simulation experiments,SSART was applied in reconstructing a non-ideal-bordered field in order to test its reconstructive effect.For contrast,three current representative algebraic reconstruction(ARTs) including basic ART,simultaneous ART (SART) and modified SART (MSART) were simulated simultaneously.The calculated results and reconstructive accuracy are discussed with three kinds of error indexes,namely mean-square error (MSE),absolute value error (AVE) and peak error (PE).As the results,the indexes of reconstructive accuracy are much improved by the proposed SSART.The MSE and PE have been decreased by 63.6% on the order of magnitude 10-4 and 88.9% on the order of magnitude 0-2,respectively,compared to that of ART.It is concluded that SSART is one of the most super iterative reconstructing techniques.
文摘This paper investigates the mathematic features of non-linear models and discusses the processing way of non-linear factors which contributes to the non-linearity of a non-linear model. On the basis of the error definition,this paper puts forward a new adjustment criterion, SGPE.Last,this paper investigates the solution of a non-linear regression model in the non-linear model space and makes the comparison between the estimated values in non-linear model space and those in linear model space.
