Pde Problem with Delta initiative condition.

The problem is to solve the heat equation $frac{partial T}{partial t} = ~frac{partial^2 T}{partial x^2}$ $T=T(x,t)$ inside a disc of radius $R$ with initial condition $T(x,0)=delta^{(2)}(x)$ and boundary conditions $T(R,t)=0$ and $x=(r,theta)%$.