I would not bring your spouse uninvited to these types of interviews/meetings. First off, many of the interviews that you have at ASTRO are of the "screening" variety. There are a ton of hungry applicants in one place and it is the perfect opportunity for employers to 'separate the wheat from the chaff'. In this type of scenario, it is too early to bring a spouse.
In my experience, spouses are welcome when you go for second visits and need to make a final decision. At this point, your spouse's input is critically important.