This volume is based on a series of lectures delivered at a one-day teach ing symposium on functional and metabolic aspects of NMR measure ments held at the Middlesex Hospital Medical School on 1st September 1985 as a part of the European Nuclear Medicine Society Congress. Currently the major emphasis in medical NMR in vivo is on its poten tial to image and display abnormalities in conventional radiological im ages, providing increased contrast between normal and abnormal tissue, improved definition of vasculature, and possibly an increased potential for differential diagnosis. Although these areas are undeniably of major importance, it is probable that NMR will continue to complement con ventional measurement methods. The major potential benefits to be de rived from in vivo NMR measurements are likely to arise from its use as an instrument for functional and metabolic studies in both clinical re search and in the everyday management of patients. It is to this area that this volume is directed."

Neuroblastoma is the third most common malignancy of childhood. accounting for 8% of all cancers in patients under 15 years of age. In the majority of cases. by the time neuroblastoma is diagnosed. it has already spread from its site of origin to involve distant sites. Approximately 90% of cases of neuroblastoma can be diagnosed by a combination of techniques including detection of specific tumour markers in the urine. histopathological and immunocytological assessment of involved bone marrow and the 'characteristic' appearances of tumours dem- onstrated by computerised tomography and ultrasonography. However. despite this plethora of techniques. up to. 10% of cases of neuroblastoma are still difficult to diagnose and rely on excisional biopsy of a site of disease. It was against this background that the scintigraphic localisation of neuroblastoma with the radiolabelled guanethidine analogue. mIBG. became available. With mIBG scintigraphy it is now possible to demonstrate the presence of neuro- blastoma (and related tumours) at the primary site. soft tissue sites. in the bone marrow and in cortical bone. in a single investigation. The success of mIBG scintigraphy depends on many factors including the choice of isotope for labelling the mIBG. the equipment used to carry out the procedure. and the manipulation and interpretation of the information obtained. At the Royal Marsden Hospital we have performed over 100 mIBG studies in children. and our advice has frequently been sought by other centres who are. or intend to become.