2 sentences for 针头 (zhēn​tóu — syringe needle)

1. 护士用针头刺入手臂输液。

   hù​shi yòng zhēn​tóu cì rù shǒu​bì shū​yè.

   The nurse inserted the needle into the arm for an IV.

   Source: Dong Chinese Dictionary

2. 护士熟练地给注射器装上了新的针头。

   hù​shi shú​liàn de gěi zhù​shè​qì zhuāng​shàng le xīn de zhēn​tóu.

   The nurse skillfully fitted a new needle onto the syringe.

   Source: Dong Chinese Dictionary