CT guided needle biopsy (TTNB - trans thoracic needle biopsy ) of pulmonary lesions is a well established diagnosis technique in pulmonology. It is most suitable for peripheral lung lesions with a diameter greater than 2 cm and for the diagnosis of a mediastinal mass. In these situations the diagnosis yield may reach up to 90% . However in smaller or "non homogenous" lesions (as to CT imaging) the yield lowers to only 60% .As usually there is no rapid onsite specimen pathologic examination (ROSE) a number of attempts (passages) are performed in order to receive a good quality sample. The complication rate of TTNB (pneumothorax or bleeding) is relatively high ( up to 15% and 5% respectively). Necrosis is a common feature of rapid growing tumors and may significantly impair the histopathological diagnosis and thus lowering the TTNB yield. Optimization of the needle position into a viable tissue area of the lesion is imperative as to improve the yield of the TTNB technique.