Percutaneous CT guided biopsy is a well-established, standard sampling technique for suspected neoplastic lesions located in peripheral region in lung parenchyma. Inconclusive results on CT guided biopsy is substantially higher in large lung lesions which are prone to cause peripheral pneumonia, atelectasis and even regional necrosis, which are hard to be distinguished from tumor on CT images. Functional imaging guided biopsy like PET/CT guided biopsy identifies areas of highest concentration of neoplastic cells and provides accurate results. Only a few studies have been done regarding PET/CT guided biopsy and studies omparing PET/CT guided and CT guided percutaneous transthoracic lung biopsy are very few and this study would be a randomized trial comparing these diagnostic modalities in terms of diagnostic yield, diagnostic accuracy of sample and complications.