3D gausian filter with nan values

Hello,

I need to do a 3D gausian filter on a 3 dimentional array I have. the problem is that my array is mostly NaN values which I don't want to 'eatup' my entire array.

I tried several forms of using imgaussfilt3 and other filter functions but for all the result is the same- I end up with an entire array of NaN.

can any1 help?