During surgery, a fine needle puncture was proceeded when suspicious nodes was found by clinician. Repeat the punction for 2-3 times from different orientation and then, Diff-quik staining or PTH immunochromatographic assay were proceeded for lymph node or parathyroid glands identification. Post-operative pathology outcome was considered as golden standard.

In the experiment group, when suspicious parathyroid glands or lymph nodes were observed, a 22 G needle was applied for in situ puncture at a 45 degree angle. The needle was initially thrust into the gland for 0.2 mm, and then we advanced the needle for another 0.2mm while gently withdrawing the plunger of the syringe and maintaining negative pressure. At this point, there has parathyroid tissue been adsorbed in the needle. Repeat this process in two different directions to guarantee the simple volume.

When cell smears finished, the smears were fixed in stationary liquid within 2-4 seconds for 5-20 seconds, and then Diff-Quik (DQ) staining technique was proceeded for rapid identification using Diff-Quik staining kit according to the instruction. After the following Diff-quick staining for 30 seconds, we can make out parathyroid cells and lymph nodes under high power microscope.

In addition,PTH immunochromatographic assay kit can also be used for parathyroid glands detection. Using indicator paper to dip to the punctured tissue, the existance of parathyroid glands could be ensured.

HE (Hematoxylin and Eosin) staining was used for pathological verification of suspicious nodes found during surgery. The suspicious nodes occurred in surgery were isolated and fixed with 4% paraformaldehyde for 12 h, embedded in paraffin and cut into 3-µm serial sections. Corresponding sections were stained with hematoxylin (BASO Diagnostics Inc. Zhuhai) for 10 min at room temperature. Then, sections were washed with running water. Subsequently, sections were washed with Scott promote blue liquid for 1 min, 1% hydrochloric acid alcohol differentiation liquid for 20 s, and Scott promote blue liquid for 1 min. Then, sections were stained with eosin (BASO Diagnostics Inc. Zhuhai) for 30 s. Sections were washed with running water and sealed for observation. Finally, sections were observed by Image-Pro Plus 5.0 software (Media Cybernetics, Inc., Bethesda, MD, USA).

Inclusion Criteria:

- Thyroid cancer patients undergoing thyroid cancer surgery Preoperative examination were all ready for surgery Diagnosed with thyroid cancer by fine needle puncture before surgery

Exclusion Criteria:

- Patients enrolled into another clinical study Pregnant patients Patients diagnosed with another life-treating disease Patients with surgical contraindication