diff --git a/nipype/interfaces/freesurfer/petsurfer.py b/nipype/interfaces/freesurfer/petsurfer.py
index 33602d2711..272cba6e21 100644
--- a/nipype/interfaces/freesurfer/petsurfer.py
+++ b/nipype/interfaces/freesurfer/petsurfer.py
@@ -557,7 +557,7 @@ def _list_outputs(self):
             outputs["rbv"] = os.path.join(pvcdir, "rbv.nii.gz")
             outputs["reg_rbvpet2anat"] = os.path.join(pvcdir, "aux", "rbv2anat.lta")
             outputs["reg_anat2rbvpet"] = os.path.join(pvcdir, "aux", "anat2rbv.lta")
-        if self.inputs.opt:
+        if self.inputs.optimization_schema:
             outputs["opt_params"] = os.path.join(pvcdir, "aux", "opt.params.dat")
 
         return outputs