The Academy of Notre Dame in Tyngsborough will welcome a new student in January who has arrived from the Republic of Ghana in West Africa to undergo medical treatment. Fifteen-year-old Theresa Boateng traveled here a month ago to live with her sister, Gifty Boateng of Lowell, while she prepares for specialized foot surgery. The procedure will be done at Children’s Hospital in Boston, most likely in March. During the next few months, Boateng will undergo preparatory medical procedures while keeping up with her studies at the academy, tuition free. The teen was introduced to school officials through the office of her pediatrician, Dr. Alena Ashenberg in Dracut; Ashenberg’s office manager is an academy alumnus, as is her mother.