So, I have what may be a dumb question, but since I'm not in the field yet I don't exactly know what I'm missing. My question is why isn't boron attempted as a treatment (or is it?) used with thermal neutrons? Everything I've read seems to say it would work wells as it can be conjugated to drugs that "somewhat" specifically target a tumor (i.e. like targeting to rapidly dividing endothelial cells). Since from what I've heard there isnt anything out there that targets tumor cells specifically enough to conjugate an alkylating agent to it or an alpha emitter, why not use boron, and then only expose to neutrons the part of the body the tumor is in so you don't need to worry about the nonspecific binding to other parts of the body? Wouldn't that be a doable thing for say head and neck cancer where the depth issue with thermal neutrons wouldn't matter? I've read some stuff from Dr. Eric Hall (@ Columbia) about how boron has a lot of promise but can't seem to see why its not used?