Tomographic reconstruction using free-form deformation models

We address the issue of using deformable models to reconstruct the shape of unknown objects in the context of 3D tomography. We focus on the reconstruction of piecewise-uniform radioactive distributions such as in blood pool or lung imaging. We represent the unknown distribution by a set of closed surfaces defining uniformly emitting regions in space. The methods implemented so far tend to directly deform the surfaces. Rather than deforming the surface models themselves, we explore the deformation of the space in which the surfaces are contained to match a set of scintigraphic measurements. We focus on the use of free-form deformations to describe the continuous transformation of space. We illustrate this approach by reconstructing simulated scintigraphic data of the lungs.