Theranostic therapies combine molecular targeted diagnostics with radionuclides for imaging and therapy in many advanced malignancies. Frequently however, due to heterogeneity of treatment response, complete remission in theranostic treatment is rare; residual lesions often progress and the treatment can induce severe symptoms. Contributing to the problem, are the number of lesions that often metastasize to other areas of the body such as bone and liver. Identifying, measuring and tracking the treatment response of numerous metastatic lesions, using standard medical images, is difficult and challenges the ability to understand the efficacy and safety of a new theranostic treatment expeditiously. This lapse of understanding can cost researchers valuable time and resources.