One of the useful biopsy technique in sampling tissue is Fine needle aspiration (FNA). It can sample superficial or deep nodules through imaging techniques, such as an ultrasound or CT. Under sterile technique, a fine needle (25G or 27G) is pierced into the nodule and rapidly moved back and forth to sample cells. This procedure may be performed several times in order to gather enough specimen. The specimen is placed on glass slides, stained, and examined under a microscope by an experienced cytopathologist in order to provide a rapid on-site adequacy assessment. Depending on the assessment, further additional tests may need for the final diagnosis.