Li-7 ions release kinetic energy just like alphas but with different dE/dx due to higher mass.

In my thesis work on liver, twenty and more years ago, the answer was that the Li burden after therapy is negligible from the chemical point of view just as Tl-208 is administrated to patient in scintigraphy without thallium poisoning effects

thank you sir.  Sir, my interest is what happens when the Li-7 ions  kinetic energy becomes   o eV

Li-7 may be teken into account as a light ions irradiation. The effect is similar to He4 in terms of release of energy inside cell, but with a slightly different dE/dx. Taking into account the Q of B-10(n,alpha)Li-7 neutron capture reactions using thermal energy neutrons  and their LET, both particles have pathway ranges (~ 8 microns alpha - ~5 microns Li7 ) in soft tissues that are within a cell diameter (i.e. ~10-20 micron).  That is basically the advantage of BNCT: a local (human cell level)  radiation therapy

In Boron Neutron Capture Therapy, the alpha is emitted with an energy of 1.84 MeV while the Li-7 is emitted with an energy of 0.84 MeV. The range of each particles is less than that of dimensions of a human cell of ~ 12 microns. Nothing happens to the Li-7 when it stops inside the tumor. The amount of the Li-7 atoms that will be accumulating inside the brain tumor after irradiation is so minute  that very probably nothing can happen in terms of poisoning or any other detectable effect.

I agree with Raymond. The alpha and Li7 will slow down over a very short distance as they loose energy in tissue then stop. They will then undergo chemical reactions within the cell where they come to rest. 

The actual number of Li7 atoms will be very small but could be calculated from a knowledge of the B10 concentration and the thermal neutron fluence. I expect this is avaiable somewhere in the literature!

thank you sir,  now i am convinced.  sir, my problem is not related to Li7 concentration, i want know what final product will form at the end of Li7 track

For all practical purposes, Li behaves like Na in an Organism. So its main form is just a solved Kation (Li+) and it will be excreted by the kidney.

Li can be found in our blood in the order of some ten mikrogramm/l. It´s a dietary mineral. So no abnormal reaction of the organism is to be expected. Excretion by the kidneys will only occur if to high levels of Li in the serum is detected by the kidneys.

all answers is true. there are many ion in blood.extra ions  Excrete by kidney.