Molecular Imaging 2017

Problem: Ground truth

• To calibrate a correct contouring method, the knowldedge on the correct tumor borders is essential, e.g. from: - Phantom-measurements Problem: usually homogenous spheres, glass wall, homogenous background = not representative for tumors - simulated images Problem: extremely harmful to produce, proximity to reality depends on assumptions - image data with histopathology correlation not many datasets available, all have shortcomings: shrinking, distortion, problem of coregistration, diffuse infiltration - tumor size known from other imaging Problem: reason for second imaging? other problems in size determination • possible surrogates: - comparison with expert contours, ideally consistent in multiple observers - visual or mathematical consensus-contour of different methods 16