The complementary role of sequential 99mTc-MDP and 67Ga-citrate scanning in the diagnosis and follow-up of neuroblastoma.

Fourteen children with histopathologically confirmed neuroblastoma underwent 38 studies using 99mTc-methylene-diphosphonate (MDP) and galliumcitrate Ga67 whole-body scintigraphy during various stages of the disease. Ten patients (71%) showed 99mTc-MDP accumulation in the primary tumoral site, whereas 11 patients (78.6%) showed 67Ga concentration. In 12 patients (86%), at least one of these two radiopharmaceuticals concentrated in the primary tumor. Nine patients had osseous or extraosseous metastases. All of these metastases (100%) were positive on 99mTc-MDP scintigraphy. No 67Ga-citrate uptake was demonstrable in osseous metastases; only one extraosseous lung metastasis concentrated this radiopharmaceutical. 67Ga-citrate was superior to 99mTc-MDP with regard to accurately demonstrating the extent of primary tumors. Only 99mTc-MDP indicated the relationship of the tumor to the kidneys and neighbouring osseous structures, providing early screening of kidney compression and possible damage caused by the tumor. From these results, we found these two methods to be complementary for the diagnosis and follow-up of neuroblastoma; their combined use resulted in high diagnostic accuracy and a considerable gain of information. We therefore recommend sequential 99mTc-MDP and 67Ga-citrate scans for the diagnosis and evaluation of the primary tumor; periodic 99mTc-MDP whole-body scans should be used in the follow-up of treatment, and for discovering disease exacerbations and metastases.