Indeed. US is a highly technical, specific skill. Even within a specific use case -- e.g. echocardiography -- there's a specific series of qualifications that cardiologists need to get in order to be deemed competent. The rotation of your hand in a specific position in transthoracic echocardiography can change the resulting ejection fraction of the heart -- the main functional outcome. It's a simple thing to see done; quite another for you to do yourself and make safe decisions.