Volume pixel determination/voxel determination

Hi! I have a virtual stack with multiple TEM slices through a sample. Each of my images is 1600 x 1200 pixels, and I have a scale bar of 10 µm micrometers on each image. When I set the scale on the images it gives me a scale of 13.2 pixels/µm. I know that each of my slices are 0.5µm thick. When I import the stack (as a virtual stack) into trakem2 (i’d like to determine volume of lipid droplets), FIJI prompts me for the slice thickness, in pixels. How do I determine this value, as my unit of measurement is µm? And is this value the same for the Voxel depth as seen under the calibration tool? Thanks!