Mean volumes of bowel within the modified RTOG PTV were @ cm ( @ ) ( with @ mm BEM ) , @ cm ( @ ) ( @-mm BEM ) , @ cm ( @ ) ( @-mm BEM ) , @ cm ( @ ) ( @-mm BEM ) , @ cm ( @ ) ( @-mm BEM ) , and @ cm ( @ ) ( @-mm BEM ) in comparison with an overlap of @ cm ( @ ) seen using the RMH technique .