Biomedical engineering is a rapidly growing field in the US and international students are interested in this program. It is an interdisciplinary field that overlaps engineering and medicine. It includes theory in traditional engineering along with topics in biology including instrumentation, biosensors, biomaterials, biomechanics, and biomedical imaging. This is a tough program and getting admission requires a decent GRE score, a good GPA, and a good TOEFL or IELTS score. Most universities that offer this program require the GRE.
While different universities have different criteria, most good universities will require calculus including differential equations, physics, circuits, a computer programming course (C++) and biology, chemistry, and organic chemistry. Here is another good article about Biomedical Engineering Schools