you're at 9 msv.. I've been told by my doctor at university of Colorado that low doses like that over time are safe, and if you are in the range of 0-10 that is low exposure.
I've had 3 studies in short time, one was huge exposure I don't even want to see it in writing/typing or think about it and those are the most dangerous, i.e. large acute exposures.
hope that helps