电离室自动曝光密度补偿值的合理选择

Reasonable selection of automatic exposure density compensation of iono-chamber

目的 介绍和讨论电离室自动曝光密度补偿值的合理选择方法,为临床摄片提供有重要价值的参考,提高X线影像质量。方法 在具备电离室自动曝光控制系统的X线机上,通过水模测式、密度测定,再与被照部位正常密度值为基准,选择合理的电离室密度补偿值,并对选用与不选用电离室密度补偿值照片的投照条件结果进行对照。结果 随机抽取选用与不选用电离室密度补偿值各100张X线照片,评价其投照条件,结果表明正常组两者间无显著性差异(P>0.05);特体组两者间有显著性差异(P<0.05)。结论 在正确选择电离室测射野的同时,还应选择合适的密度补偿值,对保证照片质量非常重要。此外还必须设置合适的kV值,一般高于自选10～20kV,相关因素必须相对固定和正确匹配。

Objective Tointroduceanddiscussthemethodsofreasonableselectionoftheautomatic exposuredensitycompensationofiono chambertoprovideimportantreferencesforclinicradiographandimprove thequalityofimages.Methods Χ raymachineswithiono chamberautomaticexposurecontrolsystemwereused inthisstudy .Comparedwiththestandardbaselineofthenormaldensityoftheobjectradiographed ,thereasonable iono chamberdensitycompensation (IDC)waschosenandcomparedwiththeradiographwithoutIDCthrougha watermodeltestanddensitymeasurement.Results Therewasnosignificantdifferencebetweentwogroups (1 0 0 filmseach)whichwererandomizelydividedtothegroupwithorwithoutIDC ,buttherewasstatisticallysignificant differenceinthespecialgroups.Conclusion ToselectsuitableIDCisveryimportantforguaranteeing radiographicquality,moreover,toestablishasuitablekVisalsonecessary ,usuallyitis 1 0to 2 0kVhigherthan theoptionedkV .Therelativefactorsmustbefixedrelativelyandbematchedcorrectly.