Why can't the Patriot Act be used to combat street gangs.?

Since the patriot act was enacted to fight terrorism, clearly street gangs fall into the category of terrorist organizations. Like many other terrorists organizations, street gangs pose a clear and present danger to the security of our nation,make thier money illegally, possess weapons of m destruction and have no qualms about using them. Gangs have killed more people than Al Qaeda, seems like a good idea to use the patriot act for something good.