1. An interactive touchscreen system comprising a conductive panel having a surface portion adapted to receive touch interactions, and a tomograph operatively connected to said conductive panel, said tomograph configured for determining conductivity of said conductive panel by generating and tomographically processing energy signals received from said conductive panel, said tomograph being further configured for incrementally improving a reconstructed tomogram estimation by integrating the output of a tomographic reconstruction algorithm having as input a unreconstructed tomogram delta derived from energy signals as being subject to change due to touch at said surface portion, said reconstructed tomogram estimation being representative of said panel conductivity properties at locations spatially correlated to a plurality of regions notionally defined over said surface portion and therefrom indicative of touch interactions, and said tomograph further configured for processing and outputting said reconstructed tomogram estimation and an indication thereof.