Scintigraphic diagnosis of lung cancer with 57Co-Bleomycin

From February 1973, a scintigraphic study with 57Co-Bleomycin was performed in 286 patients with various pulmonary diseases including primary lung cancer, metastatic pulmonary tumors, pulmonary inflammation, etc. In this study it was concluded that 57Co-Bleomycin scintigraphy was effective for diagnosis of primary lung cancer. Ninety percent of the patients with primary lung cancer revealed positive signs from (+) to (+++) on the 57Co-Bleomycin scintigram. Positivity rate on the scintigram was not influenced by difference of histological findings and classification of rentgenographic findings but by the size of tumors. Lung cancer with a lesion over 2cm in diameter was detectable by the scintigraphy in the great majority. The diameter of the smallest positive tumor was 1.5cm. However in patients with lung cancer less than 3cm in diameter only 55% showed moderately positive (++) and markedly positive (+++) signs and positive scintigram turned negative after radiation treatment with 60Co. An acurate diagnosis was possible for tumors which were masked by pleural effusion or pulmonary atelectasis. Metastatic tumors of lung cancer revealed also positive signs on the 57Co-Bleomycin scintigram. Metastatic tumors of breast cancer were negative while those of thyroid and uterine cancer were positive. Fifteen percent of patients with plumonary inflammation were positive. Twenty-two cases with pulmonary tuberculoma showed all negative scintigram. The differential diagnosis between lung cancer and pulmonary tuberculoma was possible if the tumor size exceeded 2cm in diameter. The urine of the patients who underwent injection of 57Co-Bleomycin should be carefully managed because of the long radioactivity of 57Co.