In theory yes, that is I am assuming that you are referring to a flat Sr-90 applicator plate. However the dosimetry is/would be a bit of a stab in the dark.

I should have been a little bit more specific about the answer than I was. The stab in the dark is really scientific!!! So back to the theory; I would assume to do this you would have a good understanding of the isodose curves across the applicator surface and also at depth. The memory is rather dim but I seem to remember that the that the distribution at depths is quite rounded and dose has dropped to about 50% at 1mm 30% at 2mm.

Better still I can refer you to this http://www.sciencedirect.com/science/article/pii/S0958394700000455 which will maybe convince or discourage you from carry out this procedure.

Good Luck