RescalSlope vueal from dicominfo

Hi all,

I want to extract the RescaleSlope value from dicominfo for each slice. But i have 135 slice images. This is my code to extract RescaleSlope. But still failed.

P = zeros(256, 256, 135);

for K = 1 : 135

petname = sprintf('PET_I1001_PT%03d.dcm', K);

P(:,:,K) = dicominfo(petname);

end

info=dicominfo(P(:,:,K));

[r,c,slice] = findND (info.RescaleSlope);

Anyone who can help me solve this problem???