Most clinician-scientists assume SR&ED belongs to biotech companies and engineering firms, not to the work they do at the bench or the bedside. In practice, a great deal of translational and clinical research meets the program's test. The question is whether your work set out to resolve a genuine scientific or technological uncertainty.
A registered trial that simply confirms an established protocol may not qualify. But the moment you adapt a method, develop a new assay, or work through an unknown the existing literature could not answer for you, you are likely doing exactly what SR&ED was designed to support.
The safest way to know is to look at the questions you could not answer in advance, and at the systematic work you did to answer them. That is the heart of an eligible claim. It is also, in our experience, the part researchers undervalue most.