The idea behind medical tourism is that people travel for medical care to another city / country. Earlier citizens from less developed countries used to migrate to highly developed countries where adequate medical care can be received. But this is not the case today , in order to get medical care at much cheaper costs, people move from developed countries to developing countries and naturally that is not compromising of quality standards. There may be several variables nowadays as to why people migrate from one nation to another for medical tourism.
The medical treatment you require is unavailable in your country.
In your country, the medical services you want to benefit from are illegal.