A couple questions/observations from the back of the room...
1) This list
is about as helpful as a list of average human waist sizes, with ranges.
2) Normal tissues have tighter
α/β ranges than tumors. "In general, cells from a given normal tissue show a narrow range of radiosensitivities if many hundreds of people are studied... By contrast, cells from human tumors show a very broad range of D-zero values" (Hall, 6th ed, p38). (Sorry for the outdated edition. I took radbio a long time ago.)
3) You say: "There is no reason to believe that an alpha-beta ratio calculated from a cell survival curve for hepatocytes would be the same as that derived clinically for the liver. Assuming that these are one in the same is a common error, and a misguided one at that." However, in Hall 6th ed. this cool little story is also on page 38:
The first in vitro survival curve was reported in 1956 and generated great excitement in the field of radiobiology. It was thought that at last, with a quantitative system available to relate absorbed dose with surviving fraction of cells, great strides would be made in understanding the effect of ionizing radiation on biologic materials. In particular, it was anticipated that significant contributions would be made toward understanding radiotherapeutic practice. This enthusiasm was not shared by everyone. Some researchers were skeptical that these in vitro techniques, which involved growing cells in petri dishes in very artificial conditions, would ever benefit clinical radiotherapy. The fears of these skeptics were eloquently voiced by F. G. Spear in the MacKenzie Davidson Memorial Lecture given to the British Institute of Radiology in 1957:
An isolated cell in vitro does not necessarily behave as it would have done if left in vivo in normal association with cells of other types. Its reactions to various stimuli, including radiations, however interesting and important in themselves, may indeed be no more typical of its behavior in the parent tissue than Robinson Crusoe on his desert island was representative of social life in York in the mid-seventeenth century.
The appropriate answer to this charge was given by David Gould, then professor of radiology at the University of Colorado. He pointed out that the in vitro culture technique measured the reproductive integrity of cells and that there was no reason to suppose that Robinson Crusoe's reproductive integrity was any different on his desert island from what it would have been had he remained in York; all that Robinson Crusoe lacked was the opportunity. The opportunity to reproduce to the limit of their capability is afforded to cells cultured in vitro if they find themselves in the petri dish, with temperature and humidity controlled and with an abundant supply of nutrients.
At the time, it required a certain amount of faith and optimism to believe that survival curves determined with the in vitro technique could be applied to the complex in vivo situation. Such faith and optimism were completely vindicated, however, by subsequent events. When techniques became available to measure cell survival in vivo, the parameters of the dose-response relationships were shown to be similar to those in vitro.
(Underline emphasis mine.) So how does what's in Hall square with your claim, or am I missing perhaps a finer point?
EDIT #4: Re: your list, one the most "sought after " alpha/betas is the cord and CNS alpha/beta. I agree it's <3.3 as on your list
although I guess more updated research puts this at 2. At the end of the day, if you go with 2, your tendency to avoid late CNS effects in designing novel (hypo)fractionation schemes will be more conservative. If 3, that tendency will be a little less conservative. And to wit, that tendency can vary a bit with 2 vs. 3 in one's calcs, so it'd be awfully nice if we could know that actual value in an actual patient (versus a class solution, a list, a 95% confidence interval for a population, etc. etc.).
