The postoperative detection of residual or recurrent MTC typically relies on conventional imaging techniques such as ultrasound, CT, MRI (101), and 99mTc-DMSA scintigraphy (102).There has been considerable discussion surrounding the choice of appropriate radiotracers to improve diagnostic efficacy based on postoperative changes in CEA and Ctn levels. The gene discussed is CEACAM5; the disease is medullary thyroid gland carcinoma.