Data of brain scans with 201Th and 99mTc - D.T.P.A. are studied in 43 patients. Some of the results sustained earlier data from Ancri (1978): lack of interest through vascular diseases, good sensitivity for the focalized brain lesions (24/25). But new features are underlined: occurrence of false - positive, intermediary patterns laying between normal scan and focal pathologic distributions but without etiologic correspondence. The quantified contrast is usually better with 99mTc - D.T.P.A. than with 201Th; these data challenge Ancri's ones. Actual indications of Thallium brain scan are discussed.