1nvestigator

ptk_main = PTKMain(); source_path_raw = 'C:\PATH_raw.nii'; source_path_airwaylabel = 'C:\PATH_airway.nii'; V_raw = niftiread(source_path_raw); V_airwaylabel = niftiread(source_path_airwaylabel); this works for me.

Did you set the path ? You can try to run at the same folder with .m file