We did the perfusion thing here for several rounds, SRS, and it was worth some "good time" with and for the kitteh and for us. In a way it made it easier to let go when that day came, to of course we cried.... the vet said one can never predict how long the effects of the treatment may last, and for some it lasts a surprisingly long time. Enjoy the time, is the main thing, and the chance to see kitteh feeling so much better.