Think you should be fine. Those scanners take snap shots with small bursts of Xray, not a continuous beam. They were probably just double checking the images on the screen or adjusting it to see a better image. You should have asked for hand checking anyway. Accumulated radiation exposure on even low speed film can ruin it, say if you are going through multiple scans at other airports. I bring a very heavy duty Xray bag on any long flights to reduce radiation exposure as well, its like 10lbs or so but works really well, I have checked the screens everytime they force it to go through and its a big black blob on the displays.