Amen. The one big overlooked variable IMHO. The main (only?) two determinants of how busy the linacs are: 1) number of new consults per week, 2) average number of weeks of treatment per patient. So, if you see 5 new patients a week and average treatments are five weeks long, you will treat on average 5x5 patients a day. Nowadays, with single-fx bony met tx, more hypofx of breast, GBM, prostate, and definitive lung, I'd say the average number of weeks of treatment per patient is closer to three, maybe less. That's HUGE in terms of decreasing rad onc demand... as now, if you see 5 new patients per week, daily treatments would drop to 5x3 = 15 from 5x5 =25. (This is why the pure prostate centers can be SO profitable as their average number of weeks of treatment per patient can be 9, so with just 5 new patients per week 5x9 = 45 patients under treatment per day.)
BTW, am I the only guy who uses this average number of weeks treatment "rule"? I made it up on my own, but I guess lots of other people realize this, too. If not, you're welcome