1. A method for locating a plurality of interested objects in Computed Tomography (CT) imaging, comprising: computing from projection data a first projection image at an observation direction perpendicular to a CT tomographic plane by means of a projection synthesis algorithm; selecting two projection images, referred as a second projection image and a third projection image, from a cone beam projection perpendicular to the observation direction, the second projection image being substantially orthogonal to the third projection image; determining locations of the plurality of interested objects in the first, second and third projection images; and computing locations of each of interested objects in the three-dimensional space based on the locations of the plurality of interested objects in the first, second and third projection images.