Growth arrest, as you note, has been reported. However, it's very rare. There just isn't enough data to make firm recommendations about X-ray monitoring. I can tell you that it isn't standard practice to obtain such X-rays. As to how reliably predictive they are of side-effects, I simply don't know.
Dr. Rockoff
I was taken off right away once we figured out what was going on. My dermatologist retired and the new one 3 months later said "Have you ever tried accutane?" and I said "Did you even look at my medical history?".
I did not go back.
Best luck!