dprime analysis question

Hi Stats experts,

I have a question about dprime analysis.
I have a task where participants listen to sentence stimuli and respond to each sentence by clicking some words.
For the response to each item, there are 8 words given and participants can click as many words as they want.
However, among those 8 words, only 2 words are the target words (hit) and the other 6 are distractors (false alarm if they click it).
In this case where the number of the hit and false alarm differs, can I still use the dprime analysis?
I feel that the ratio for the hit and the false alarm is different and so I can't do that analysis.
However, one of my committee members suggested me to do it.
It seems that the signal detection theory can be done for a binary choice. However, mine is not since the listeners can choose more than one option for each item in the task.

Please please help me with this issue. I've been struggling from this for a month!
Thanks a lot in advance.