Are you practicing for you own clinic or you are working for someone else?
If you are working for your own and it is you own business and practice and you are sincere in directing Your patients to that place as it is the best, the commission you get is permissible.
But if you work for someone else, such a commission is a bribe and you are not allowed to take it.

When a doctor asks patient to get some scan or tests done, that scan center or diagnostic center will give 10% to 20% of the bill amount to doctor after receiving the fee from patient. So my question is- can we accept this amount? Even I Don accept that amount will be used to by the scan center itself. Can I use that referral benefit amount for myself or should I accept and give in sadaqa?