I am not sure of the type of certification you have in Israel, but unless it is NREMT, you will most likely have to retake an EMT course. Even if it is NREMT, in the US each state has their own requirements, so it would be based on which state you plan to live/practice in. Many of the states now require you to be NREMT certified first in order to get state certification as well. Some states have a separate/additional written and or skills tests. And to confuse matters more, not every state recognizes NREMT, and you can only be certified through the state. So it really depends on the state you are going to, and what their requirements are.