The present invention relates to a method to assist in the determination of therapy for a patient suffering from Barretts oesophagus, especially where first-line therapy has been unsuccessful and when dysplasia has been diagnosed. The method comprises the use of an imaging agent comprising a vector which targets (a) Her2, (b) cMet, (c) guanylyl cyclase or (d) IGF1R. The imaging agent is suitable for radioisotope or optical imaging in vitro or preferably in vivo.
