There was a significant increase in external radiation exposure using the RRA versus LRA ( head : median : @ -LSB- interquartile range ( IQR ) : @ to @ -RSB- mRems vs. median : @ -LSB- IQR : @ to @ -RSB- mRems , p = @ ; thyroid : median : @ -LSB- IQR : @ to @ -RSB- mRems vs. median : @ -LSB- IQR : @ to @ -RSB- mRems , p = @ ) .