[Diagnostic value of ytterbium 169 citrate in cancerology]

Several radio-nuclides are used in Cancerology for their tumoral tropism and, in fact, 67 gallium citrate and 57Co bleomycin almost exclusively. But, these nuclides have some disadvantages, such as we tried to evaluate the interest to 169 ytterbium citrate; this radiolanthanide has already been studied in animals for its affinity for tumoral and normal tissues by HISADA and al. [5]. Our preliminary study has been made on 44 patients bearing different neoplastic diseases. In 8 cases, we have measured the percent radioactivity excreted by urines and stools in 5 days following injection. Scintigraphy of most of the patients has been made at 48 hours, but for several cases of non malignant or malignant pulmonary diseases, a cinetic study allowed us to follow the evolution of the intensity the pathological fixation. The results show: -- a weak urinary and fecal excretion; -- a good scintigraphic contrast from 48 hours; -- an important radioactive fixation in bone metastasis of various origins, in primary and secondary brain and liver tumors; -- an important radioactive fixation in lung cancers and inflammatory diseases however our preliminary cinetic study seems to be a good mean of differential diagnosis. At the cost of a non negligeable irradiation dose of bone, the tumoral fixation can be considered as good and the cinetic studies we intend to develop will perhaps improve the specificity of the diagnosis.