雙光子吸收法是一種用於測定身體的骨礦含量的放射性元素分析方法。
基本介紹
- 中文名：雙光子吸收法
- 外文名：dualX-ray energy absorptiometry
- 縮寫：DPA
- 用途：髖等全身部位的骨礦含量
概述,英文名,設備要求,操作步驟,優點,缺點,補充說明,
概述
雙光子吸收法(DPA)採用能發射兩種不同能量光子的核素作放射源，利用高能和低能射線通過被測部位的不同衰減分布來計算骨的能量衰減分布，故可用來測量一些軟組織變異大的部位如脊椎、髖等全身部位的骨礦含量，從而消除軟組織及脊髓對測量結果的影響。
英文名
dualX-rayenergyabsorptiometry
設備要求
DEXA machine,which different iatesbody weightintothecomponentsofleansofttissue,fatsofttissueandbone,basedonthedifferentialattenuationbytissuesoftwolevelsofx-rays.
操作步驟
Thepersonlaysonthewholebodyscanner,withthex-raysourcesmountedbeneathatableandadetectoroverhead.Thepersonisscannedwithphotonsthataregeneratedbytwolow-dosex-raysatdifferentenergylevels.Thebody'sabsorptionofthephotonsatthetwolevelsismeasured.Theratioscanbethenusedtopredicttotalbodyfat,fat-freemass,andtotalbodybonemineral.Theprocedurecantakeabout10-20minutes.
優點
Thismethodisprecise,accurate,andreliable.DEXAmeasurementsarebasedonathreecompartmentalmodel(totalbodymineral(frombones),fat-freesoft(lean)mass,andfattissuemass)ratherthantwocompartmentasinmostothermethods.DEXAcanalsodistinguishregionalaswellaswholebodyparametersofbodycomposition.Assuch,itisconsideredareferencestandard,andthelatestbodycompositionresearchusesthismethod.
缺點
Theequipmentisexpensive,andoftenrequirestrainedradiologypersonneltooperate.
補充說明
Ifnotforthelimitingpriceofmeasurement,DEXAwouldbeconsideredthecriterionmethodofbodycompositionanalysis
