[Scintigraphy with radiogallium in oncologic and non-oncologic diseases. State of the art and main indications].

Gallium-67 citrate (67Ga) can be considered one of the most widespread viability radiotracers. Several papers have recently been published on the use of 67Ga in different diseases, with emphasis on its value in the management of lymphoma patients. This paper critically discusses the role of gallium scintigraphy in several diseases on the basis of our personal experience and of the latest literature data, to integrate the diagnostic knowledge of radiologists, oncologists, nuclear medicine and laboratory physicians. From a clinical point of view, the best application is in neoplastic diseases, particularly lymphoma, but also in inflammatory conditions. Gallium scan sensitivity is very high (80-90%) in the staging and follow-up of Hodgkin's and non-Hodgkin's lymphoma and this method is also of great importance during the follow-up of lymphoma patients. We recommend scintigraphy to study the residual mediastinal mass after treatment. The recent experience of the National Cancer Institute (Milan) in the follow-up of 189 lymphoma patient showed the major role of gallium scan, compared with MRI, in the study of the mediastinal region after treatment. Both sensitivity and specificity were very high (90 and 96.9% vs 88.7 and 89.2% respectively). Gallium scintigraphy can also be used to study the disease-free interval, post-treatment survival, the early signs of a recurrence and also of treatment response times. The comparison of the survival curves of 33 diffuse large cell non-Hodgkin's lymphoma patients, examined at the National Cancer Institute, showed a statistically significant difference (log-rank test: p = 0.0125) between patients with positive and negative gallium scan after 4-6 cycles of chemotherapy. As for inflammatory diseases, gallium scintigraphy can play a major diagnostic role in pulmonary conditions, e.g., sarcoidosis, in AIDS-related respiratory diseases, in pneumoconiosis and in some cases of "fever of unknown origin". The contribution of this technique consists in localizing an infection focus and assessing the inflammatory disease activity, thus permitting a better therapeutic approach.