Mine was all over in 20 minutes - which included being called, walking to the room. Having the first scan on the outside, going to the toilet to empty my bladder, waiting for another room and having the large penis camera scan done (I think it's probably not called that), getting dressed and walking to reception, handing over $150 and walking to my car.
Are you having an ultrasound or a hysterosalpingogram?
Ultrasound will take 20 mins and you may have a probe used on your abdomen and up your vagina (the large penis camera scan- lol- I'll tell my patients that!).
If its an HSG, it'll take about the same, but it involves having a speculum put in (like when you have a smear), a tube placed into your uterus and dye injected through the tube to show up the fallopian tubes. Xrays are taken at the same time.