The knowledge of the carcinogenetic and cytotoxic mechanisms of asbestos in living organism is still uncomplete, also due to a lacking characterization of the asbestos modifications during its prolonged stay in the biological tissue. To gain new knowledge on the structural modifications of asbestos, and on the chemical composition of the asbestos bodies (i.e. the ensemble of the original asbestos and of the Fe-coating it develops in the tissues), we propose to perform single crystal nano-XRD measurements on Asbestos Bodies (AB) and Asbestos Fibers (AF) recovered from the lung tissues of exposed workers by a non-invasive approach based on their magnetic properties, and on AB and AF still embedded in the original lung tissues.