简介:Traditionally,bonestructureandbonemassareassessedbyobservingtherari-fiedboneonstandardx-rayfilms.However,smallchangesinbonemasscannotbedetectedeffectively.Bythetimelossofbonemasscanbedetectedonthex-ray,thediseaseisalreadyinanadvancestage.Atleast30%ofbonemustbelostbeforeproblemslikeosteoporosiscanbediagnosed.