My mother was unknowingly exposed to radiation from some radium needles (Ra-226). The exposure was at waist height, from a distance of about 25cm, for a total duration of about 1.25 hours. This happened some years ago and she was not wearing any protective clothing.
I'm assuming that the exposure was only to gamma radiation, since the radium was inside a patient being treated for cervical cancer, and so the alpha and beta radiation would have been absorbed.
I've been trying to work out how much radiation she was exposed to, but I've got stuck. I've discovered from this page that radium needles typically contained between 1mg and 10mg of radium each. I'm assuming there were three needles that each contained 5mg.
I've seen this page and I've tried to calculate it using the exposure rate constant for Ra-226, but I think I went wrong. I don't know whether this is the correct way to calculate the exposure anyway. Ideally I would like to know the equivalent dose.
Please can someone help?