It's difficult to answer your question without observing you and your work environment. I know when I started in Radiology, it took 1-2 yr for the techs to warm up to me. I was the second RN they'd ever had, and as the first one was AWESOME (we worked together), I had large shoes to fill.
Are you the only RN? Are you the first RN the dept has ever had? Has the dept organization been turned upside-down re: reassigning responsibilities/tasks from techs to you? They may be feeling threatened just by your presence in the dept. My gut is, it will take time to win their confidence and loyalty. I advise tincture of time, diplomacy, professional behavior and putting the patient first at all times. There will always be some days we'll be served (and eat) Humble Pie. A good listening ear and, thinking twice before opening mouth once both help too. Be willing to learn from their experience and knowledge, too. They don't really know what the nursing scope of practice is; it's our job to advocate for our pts, making our actions and decisions evidence-based. Sometimes it IS a tightrope we walk!
Here I said I couldn't give advice without knowing more of the situation, and then I go and spout off! Perhaps I've over-stepped myself, and if so I apologize. I wish you luck in your transition. ------- D