Concepts studied in qualitative research can be transformed into quantifiable concepts through transferring from the variables discovered in the qualitative study and converting them into quantitative ones.
Qualitative approaches do not generally use the language of variables, and many of them would not agree with using pre-conceived concepts as your starting point. In contrast, quantitative research frequently "operationalizes" concepts into measurable variables.
I think you need to be clear about what your goals are before you reach the point of considering concepts versus variables. For example, are you testing hypotheses or generating them?
Yes, it is possible to convert concepts into variables in quantitative research by operationalizing the concepts and defining measurable indicators for them.