Too slow using int, want to replace with integral2 or integral 3?

I am trying to solve a double integral in Matlab using two int functions, the equation is in spherical coordinate. It takes too long and sometimes gives an out of memory message, is there a way to solve this integration in the spherical coordination using integral2 or integral3 built-in functions?

if true
  % code
end
syms theta phi real
sin_alpha    = sin(theta)*cos(phi);
sin_beta     = sin(theta)*sin(phi);
Term1        = repmat((0:4-1)*sin_beta,4,1);
Term2        = repmat((0:4-1)*sin_alpha,4,1)';
AF_Field     = sum(sum(exp(1i*(Term1+Term2)),2));
U    = abs((AF_Field)).^2;                  % Radiation Intensity
L1   = 0; L2 = pi;                          % limits for theta
L3   = 0; L4 = 2*pi;                        % limits for phi
I1   = int(U*sin(theta),theta,L1,L2);       % theta-integral
I    = int(I1,phi,L3,L4);                   % phi-integral
Prad = double(I);