There's no risk with ultrasound so if you can afford it then get it done as often as you feel is necessary,when I had my transvaginal scan done we only needed to do the pelvis as there were no masses anywhere and the ovaries were practically gone,my consultant said at last someone in your area who had used a bit of common sense and not used unnecessary procedures what a relief it was.as you say well worth the money 😘Jeanie