I'm not GP, but https://www.trade.gov/survey-international-air-travelers-sia... suggests that in 2024 about 0.4% of European travellers to the US told the government they were coming to receive medical treatment, and https://www.trade.gov/feature-article/december-and-annual-20... says about 13 million people from Western Europe visited the US in 2024, and if you multiply those numbers you get 50k.