This is the 516th most frequent Korean word.
치료
Treatment or therapy.
In this case, "치료" again refers to 'treatment', as a noun indicating the concept or process of medical care being discussed costs.
치료 비용이 상당히 높아서 걱정입니다.
The cost of treatment is quite high, so I am concerned.
In this sentence, "치료" is used as a noun meaning 'treatment', specifically referring to medical or therapeutic care.
의사는 환자를 치료하는 일을 합니다.
The doctor works to treat patients.
Here, "치료" is associated with the verb 'do' to describe the action of treating a disease.