There are two main functions of puncture needles: first, to place a tube for drainage after puncture; second, to puncture out a small amount of tissue for pathological examination or cytological examination. For example, if there is fluid in the thoracic cavity or fluid in the abdominal cavity or abdominal infection, puncture can be performed under ultrasound guidance, usually at the most superficial part of the body surface, in order to reduce collateral damage. If a patient suspects a tumor in a certain area and the diagnosis cannot be confirmed by imaging, pathological examination is required, such as thyroid nodules, breast nodules or suspected cancer, and if the pathology confirms that the nodule is a malignant tumor, a clear diagnosis can be made.