diff --git a/src/io/import/importDataSources.ts b/src/io/import/importDataSources.ts
index 656192b6..bdcd11f9 100644
--- a/src/io/import/importDataSources.ts
+++ b/src/io/import/importDataSources.ts
@@ -172,20 +172,21 @@ export type ImportDataSourcesResult = Awaited<
   ReturnType<typeof importDataSources>
 >[number];
 
-export function convertSuccessResultToDataSelection(
-  result: ImportDataSourcesResult
-) {
-  if (!isSelectable(result)) return null;
-
-  const { dataID, dataType } = result.data[0];
-
+export function toDataSelection(loadable: LoadableResult) {
+  const { dataID, dataType } = loadable;
   if (dataType === 'dicom') {
     return makeDICOMSelection(dataID);
   }
-
   if (dataType === 'image') {
     return makeImageSelection(dataID);
   }
-
   return null;
 }
+
+export function convertSuccessResultToDataSelection(
+  result: ImportDataSourcesResult
+) {
+  if (!isSelectable(result)) return null;
+
+  return toDataSelection(result.data[0]);
+}
diff --git a/src/store/datasets-layers.ts b/src/store/datasets-layers.ts
index 880a68da..a7625629 100644
--- a/src/store/datasets-layers.ts
+++ b/src/store/datasets-layers.ts
@@ -76,6 +76,9 @@ export const useLayersStore = defineStore('layer', () => {
       [parent, source].map(getImage)
     );
 
+    if (!sourceImage) {
+      throw new Error('Failed to load layer image');
+    }
     if (
       !vtkBoundingBox.intersects(
         parentImage.getBounds(),
@@ -110,9 +113,18 @@ export const useLayersStore = defineStore('layer', () => {
     parent: DataSelection,
     source: DataSelection
   ) {
-    return useErrorMessage('Failed to build layer', () =>
-      this._addLayer(parent, source)
-    );
+    return useErrorMessage('Failed to build layer', async () => {
+      try {
+        await this._addLayer(parent, source);
+      } catch (error) {
+        // remove failed layer from parent's layer list
+        const parentKey = toDataSelectionKey(parent);
+        this.parentToLayers[parentKey] = this.parentToLayers[parentKey]?.filter(
+          ({ selection }) => !selectionEquals(selection, source)
+        );
+        throw error;
+      }
+    });
   }
 
   function deleteLayer(
diff --git a/src/store/load-data.ts b/src/store/load-data.ts
index c0533f34..7d72cb71 100644
--- a/src/store/load-data.ts
+++ b/src/store/load-data.ts
@@ -1,10 +1,16 @@
-import { partitionResults } from '@/src/core/pipeline';
+import { PipelineResultSuccess, partitionResults } from '@/src/core/pipeline';
 import { DataSource, getDataSourceName } from '@/src/io/import/dataSource';
 import {
   ImportDataSourcesResult,
-  convertSuccessResultToDataSelection,
   importDataSources,
+  toDataSelection,
 } from '@/src/io/import/importDataSources';
+import {
+  ImportResult,
+  LoadableResult,
+  isLoadableResult,
+} from '@/src/io/import/common';
+import { useDICOMStore } from '@/src/store/datasets-dicom';
 import { useDatasetStore } from '@/src/store/datasets';
 import { useMessageStore } from '@/src/store/messages';
 import { Maybe } from '@/src/types';
@@ -14,6 +20,9 @@ import { computed, ref, watch } from 'vue';
 import { useToast } from '@/src/composables/useToast';
 import { TYPE } from 'vue-toastification';
 import { ToastID, ToastOptions } from 'vue-toastification/dist/types/types';
+import { useLayersStore } from './datasets-layers';
+
+const BASE_MODALITY_TYPES = ['CT', 'MR', 'DX', 'US'];
 
 const NotificationMessages = {
   Loading: 'Loading datasets...',
@@ -103,6 +112,71 @@ function useLoadingNotifications() {
   };
 }
 
+function pickBaseDicom(loadableDataSources: Array<LoadableResult>) {
+  // pick dicom dataset as primary selection if available
+  const dicoms = loadableDataSources.filter(
+    ({ dataType }) => dataType === 'dicom'
+  );
+  // prefer some modalities as base
+  const dicomStore = useDICOMStore();
+  return dicoms.find((dicomSource) => {
+    const volumeInfo = dicomStore.volumeInfo[dicomSource.dataID];
+    const modality = volumeInfo?.Modality;
+    return BASE_MODALITY_TYPES.includes(modality);
+  });
+}
+
+function pickLoadableDataSources(
+  succeeded: Array<PipelineResultSuccess<ImportResult>>
+) {
+  return succeeded.flatMap((result) => {
+    return result.data.filter(isLoadableResult);
+  });
+}
+
+function pickBaseDataSource(
+  succeeded: Array<PipelineResultSuccess<ImportResult>>
+) {
+  const loadableDataSources = pickLoadableDataSources(succeeded);
+  const baseDicom = pickBaseDicom(loadableDataSources);
+  return baseDicom ?? loadableDataSources[0];
+}
+
+function getStudyUID(volumeID: string) {
+  const dicomStore = useDICOMStore();
+  const studyKey = dicomStore.volumeStudy[volumeID];
+  return dicomStore.studyInfo[studyKey].StudyInstanceUID;
+}
+
+function loadLayers(
+  primaryDataSource: LoadableResult,
+  succeeded: Array<PipelineResultSuccess<ImportResult>>
+) {
+  if (primaryDataSource.dataType !== 'dicom') return;
+  const dicomDataSources = pickLoadableDataSources(succeeded).filter(
+    ({ dataType }) => dataType === 'dicom'
+  );
+  const studyID = getStudyUID(primaryDataSource.dataID);
+  const otherVolumesInStudy = dicomDataSources.filter((ds) => {
+    const studyUID = getStudyUID(ds.dataID);
+    return studyUID === studyID && ds.dataID !== primaryDataSource.dataID;
+  });
+  const dicomStore = useDICOMStore();
+  const primaryModality =
+    dicomStore.volumeInfo[primaryDataSource.dataID].Modality;
+  // Look for one PET volume to layer with CT.  Only one as there are often multiple "White Balance" corrected PET volumes.
+  const toLayer = otherVolumesInStudy.find((ds) => {
+    const otherModality = dicomStore.volumeInfo[ds.dataID].Modality;
+    return primaryModality === 'CT' && otherModality === 'PT';
+  });
+  if (!toLayer) return;
+
+  const primarySelection = toDataSelection(primaryDataSource)!;
+  const layersStore = useLayersStore();
+  const layerSelection = toDataSelection(toLayer)!;
+  layersStore.addLayer(primarySelection, layerSelection);
+}
+
 const useLoadDataStore = defineStore('loadData', () => {
   const { startLoading, stopLoading, setError, isLoading } =
     useLoadingNotifications();
@@ -132,9 +206,11 @@ const useLoadDataStore = defineStore('loadData', () => {
     const [succeeded, errored] = partitionResults(results);
 
     if (!dataStore.primarySelection && succeeded.length) {
-      const selection = convertSuccessResultToDataSelection(succeeded[0]);
+      const primaryDataSource = pickBaseDataSource(succeeded);
+      const selection = toDataSelection(primaryDataSource);
       if (selection) {
         dataStore.setPrimarySelection(selection);
+        loadLayers(primaryDataSource, succeeded);
       }
     }