treat with/by? (healthcare)

I am not sure about the correctness of using “treated by” (in the healthcare context) with medical devices - can you be treated both WITH and BY radiation? Where there is also a human agent, I suppose English speakers would prefer using two different prepositions (you are treated BY a doctor/nurse WITH a drug or a device). But where there is only a device or a drug in the sentence, I am not so sure, though I would opt for “with” as the safer alternative. With drugs, especially, “by” seems to me inappropriate. Can someone help me? Thank you very much. S.

I just have the same thoughts as you because devices are not direct doer(who does the actions). We usually use by when saying something or someone is directly irritated by someone or something else. For ex, he was beaten by gangsters which means the gangsters beat him directly.

This is definitely NOT the case, Susan. Native speakers pay no attention to repeated prepositions; it is learners who try to avoid them and thereby end up with the wrong ones.

Treated by radiotherapy with radiation.
Treated with penicillin by a doctor with a long needle.

Thank you, Mr. Micawber, I´ll keep in mind what you said about native speakers :slight_smile: But otherwise, from what you write I gather my instincts were basically right - “with” with drugs or devices such as the needle, and also for radiation as opposed to radioatherapy, since radiation can be thought of more as an “instrument” than radiotherapy (radioatherapy is a whole process and you are not treated “with” a process). S.

Right you are.