 Insulinomas arise from pancreatic cells and are the most frequent hormone-active tumours of the pancreas. Insulinomas produce insulin and can become life threatening if they cannot be localised and removed surgically. Complete tumour resection cures most patients, hence surgery is the treatment of choice for begin and malignant insulinomas. The potential for surgical cure necessitates accurate tumour localisation before surgery because preoperative imaging facilitates the detection of small localised, multiple and metastatic insulinomas. However, the successful localisation of insulinomas is an challenging problem since approximately 30 of insulinomas cannot be visualised radiographically. 