Thorium dioxide.
D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000000981:diagnostic imaging*; D006801:Humans; D009333:Neck / Q000000981:diagnostic imaging; D013902:Radiography, Thoracic; D013154:Spleen / Q000000981:diagnostic imaging; D013911:Thorium Dioxide / Q000009:adverse effects*
D013911:Thorium Dioxide