The study consists of preclinical (to establish a clinically useful formulation for the radiolabelled peptide CP04), and a clinical step. The main objective of the clinical part of the project is to establish the safety of i.v. administration of a high peptide amount and to assess the tracer biodistribution and dosimetry in MTC and normal tissues and to determine critical organs as well as the evaluation of the potential of CCK2 receptor scintigraphy to detect cancer lesions for both low (10ug) and high (50ug) peptide amount and the decrease of kidney dose after co-administration of gelofusine /gelaspan as a nephroprotective agent. To achieve this, the following study design has been accepted: the first 4 patients will receive 2 peptide amount of CP04: low peptide amount (for diagnostic purpose) and high peptide amount (for therapeutic purpose) of CP04. If no SAE is present, the remaining pts will be randomized for 2 arms: high peptide amount of 111In-CP04 with and without gelofusine/gelaspan infusion.