diff --git a/src/schema/meta/templates.yaml b/src/schema/meta/templates.yaml
index 4e7aa668a0..573051d338 100644
--- a/src/schema/meta/templates.yaml
+++ b/src/schema/meta/templates.yaml
@@ -153,6 +153,19 @@ deriv:
       segmentation: optional
       scale: optional
 
+  pet_derivative:
+    $ref: meta.templates.deriv.volumetric
+    extensions:
+      - .gii
+      - .gii.gz
+      - .nii.gz
+      - .nii
+      - .json
+    suffixes:
+      - pet
+    entities:
+      $ref: meta.templates.deriv.volumetric.entities
+
 # Entities that apply to most atlas files
 # Include thus:
 #
diff --git a/src/schema/objects/suffixes.yaml b/src/schema/objects/suffixes.yaml
index 37cca59edf..05a389ada2 100644
--- a/src/schema/objects/suffixes.yaml
+++ b/src/schema/objects/suffixes.yaml
@@ -727,6 +727,7 @@ meg:
   description: |
     Unprocessed MEG data stored in the native file format of the MEG instrument
     with which the data was collected.
+
 motion:
   value: motion
   display_name: Motion
diff --git a/src/schema/rules/checks/atlas.yaml b/src/schema/rules/checks/atlas.yaml
index 66b127a99b..1540de8604 100644
--- a/src/schema/rules/checks/atlas.yaml
+++ b/src/schema/rules/checks/atlas.yaml
@@ -1,3 +1,4 @@
+---
 AtlasDescriptionRequired:
   issue:
     code: ATLAS_DESCRIPTION_REQUIRED
diff --git a/src/schema/rules/checks/eyetrack.yaml b/src/schema/rules/checks/eyetrack.yaml
index 7f2765b98a..f6133ba02f 100644
--- a/src/schema/rules/checks/eyetrack.yaml
+++ b/src/schema/rules/checks/eyetrack.yaml
@@ -1,3 +1,4 @@
+---
 EyetrackingStimulusPresentation:
   issue:
     code: INCOMPLETE_STIMULUS_PRESENTATION
diff --git a/src/schema/rules/files/deriv/atlas.yaml b/src/schema/rules/files/deriv/atlas.yaml
index 126dad7208..2f835d0ecc 100644
--- a/src/schema/rules/files/deriv/atlas.yaml
+++ b/src/schema/rules/files/deriv/atlas.yaml
@@ -1,3 +1,4 @@
+---
 atlas_description:
   selectors:
     - dataset.dataset_description.DatasetType == 'derivative'
diff --git a/src/schema/rules/files/deriv/imaging.yaml b/src/schema/rules/files/deriv/imaging.yaml
index d4fad4e68c..dc6b2ebf10 100644
--- a/src/schema/rules/files/deriv/imaging.yaml
+++ b/src/schema/rules/files/deriv/imaging.yaml
@@ -385,19 +385,26 @@ perf_asl_volumetric_atlas:
 
 pet_pet_volumetric:
   $ref:
-    - meta.templates.deriv.volumetric
+    - meta.templates.deriv.pet_derivative
     - rules.files.raw.pet.pet
   entities:
     $ref:
-      - meta.templates.deriv.volumetric.entities
+      - meta.templates.deriv.pet_derivative.entities
       - rules.files.raw.pet.pet.entities
+    atlas: optional
+    hemisphere: optional
+    template: optional
+    scale: optional
+    label: optional
+    segmentation: optional
 
 pet_pet_volumetric_atlas:
   $ref: rules.files.deriv.imaging.pet_pet_volumetric
   entities:
     $ref:
-      - meta.templates.deriv.volumetric.entities
+      - meta.templates.atlas.base.entities
       - rules.files.deriv.imaging.pet_pet_volumetric.entities
+    subject: optional
 
 # Masks
 anat_mask: