The aim of the study was to determine whether a thin-gauge transthoracic biopsy needle would be deflected from a straight path as it passed through lung tissue, and whether partially withdrawing the needle and reinserting it while applying pressure could significantly change the degree of deflection. Using a cadaver lung, we showed that the needle tip was deflected, on average, 2.5 mm from a straight path in a direction opposite to the bevel. The reinsertion technique using pressure caused the average deflection to increase to 6.3 mm, a significant difference from the previous value. We have found this technique to be useful in the performance of transthoracic needle aspiration biopsy of small deep pulmonary nodules where differences in positioning of the needle tip by only a few millimeters can achieve the correct, rather than an indeterminate, diagnosis.