Seperating a montage/mosaic of DICOM images in to individual slices

HI,

I have a 3D matrix of 256 X 256 X 128 (means 128 images of 256 X 256 resolution). Within one of these images there are 10 slices which are each 64X64. I need to separate each of these slices. The way the images are displayed in each image is 4 in the first row, 4 in the second row and 2 in the 3rd row. So far I have written a loop that goes through all the 128 dicom images. Within that loop I have the start and end point pixel numbers on the x direction and y direction. They run from xbegin and ybegin=1,65,129,193 and xend and yend=64,128,192 and 256. Although the loop does run through it doesn't go further from the first slice in the first image. Please let me know what I am doing wrong. Thanks. Here is the code I have so far.

No_of_DICOM_Files=128;
Dimension_Slice_Side=64;
Data_Structure.Image___Matrix_3D(:,:,:)=The original image matrix of 256 by 256 in to 128 images
delta=256/64% size of original DICOM/side of individual slice

for index1=1:No_of_DICOM_Files
  Matrix(:,:,:)=Data_Structure.Image___Matrix_3D(:,:,:);
  for index2=1:delta 
      ybegin(index2)=(index2*Dimension_Slice_Side)-63;
      yend(index2)=index2*Dimension_Slice_Side;
      for index3=1:dx
          xbegin(index3)=(index3*Dimension_Slice_Side)-63;
          xend(index3)=index3*Dimension_Slice_Side;
          for index4=1:16
Matrix22(xbegin:xend,ybegin:yend,:,index4) = Matrix(xbegin:xend,ybegin:yend,:);
          end

            disp(['The x direction (index3) :' ,sprintf(' %u' ,index3)]);
            disp(['The y direction (index2) :' ,sprintf(' %u' ,index2)]);
            disp(['Image Number    (index1) :' ,sprintf(' %u' ,index1)]);

        end
    end