Bone marrow scintigrams (MS) combined with single photon emission computed tomographic investigation of the liver (liver SPECT) were obtained using 99Tcm-labelled human serum albumin nanosized colloids in 52 patients with histologically proven lung carcinomas (adenocarcinomas = 17, squamous cell = 16, small cell = 14, large cell = 5, 31 generalized cases at the time of the first MS investigation among whom 13 patients had proven skeletal metastases). They were compared with conventional bone scintigrams (BS) as well as clinical, biological, radiological and follow-up data obtained for the same patients. In the present series, MS appeared as sensitive as BS in diagnosing skeletal metastases (77%) if all abnormal MS and BS presentations are considered as diagnostic, but more sensitive (77% versus 54%) if more restrictive analytical criteria are applied. The two investigations yielded the same specificities whatever the analytical criteria applied. These preliminary conclusions have, however, to be confirmed on larger populations than the present series. The most striking differences between BS and MS were observed in the case of small-cell lung carcinomas, with more lesions detected by MS than by BS. Liver SPECT also made it possible to diagnose seven and to suspect one out of the ten situations of hepatic metastases. The combination of liver spect and MS in the framework of a single injection of 99Tcm-labelled nanosized colloids thus allowed us to diagnose 80% of the patients with osseous and/or hepatic metastasis or 40% of all generalized cases.