Unfortunately, you cannot. Your parents do not meet the second part of the qualifications for a dependent. They are not citizens of the U.S, Canada, or Mexico.
You can generally include medical expenses you pay for yourself, as well as those you pay for someone who was your spouse or your dependent either when the services were provided or when you paid for them.
You can include medical expenses you paid for your dependent. For you to include these expenses, the person must have been your dependent either at the time the medical services were provided or at the time you paid the expenses. A person generally qualifies as your dependent for purposes of the medical expense deduction if both of the following requirements are met.
The person was a qualifying child (defined later) or a qualifying relative (defined later).
-
The person was a U.S. citizen or national or a resident of the United States, Canada, or Mexico.
More on this topic on page 3:
https://www.irs.gov/pub/irs-pdf/p502.pdf
