diff --git a/src/app/application.js b/src/app/application.js
index c0ccc44ffa..23ffbbd5fc 100644
--- a/src/app/application.js
+++ b/src/app/application.js
@@ -25,7 +25,7 @@ import {toolList, defaultToolList, toolOptions} from '../tools';
 import {binderList} from '../gui/stage';
 import {WindowLevel} from '../image/windowLevel';
 import {PlaneHelper} from '../image/planeHelper';
-import {AnnotationGroup} from '../image/annotation';
+import {AnnotationGroup} from '../image/annotationGroup';
 
 // doc imports
 /* eslint-disable no-unused-vars */
diff --git a/src/app/dataController.js b/src/app/dataController.js
index 7b398d897c..49da6e7c53 100644
--- a/src/app/dataController.js
+++ b/src/app/dataController.js
@@ -4,7 +4,7 @@ import {mergeObjects} from '../utils/operator';
 // doc imports
 /* eslint-disable no-unused-vars */
 import {Image} from '../image/image';
-import {AnnotationGroup} from '../image/annotation';
+import {AnnotationGroup} from '../image/annotationGroup';
 /* eslint-enable no-unused-vars */
 
 /**
diff --git a/src/app/drawController.js b/src/app/drawController.js
index 8a5bb659ad..5b8d23c6a1 100644
--- a/src/app/drawController.js
+++ b/src/app/drawController.js
@@ -1,4 +1,4 @@
-import {AnnotationGroup} from '../image/annotation';
+import {AnnotationGroup} from '../image/annotationGroup';
 import {
   RemoveAnnotationCommand,
   UpdateAnnotationCommand
diff --git a/src/gui/drawLayer.js b/src/gui/drawLayer.js
index 3a0883c4f7..204a1afea4 100644
--- a/src/gui/drawLayer.js
+++ b/src/gui/drawLayer.js
@@ -21,7 +21,8 @@ import {Index} from '../math/index';
 import {Vector3D} from '../math/vector';
 import {Scalar2D, Scalar3D} from '../math/scalar';
 import {PlaneHelper} from '../image/planeHelper';
-import {Annotation, AnnotationGroup} from '../image/annotation';
+import {Annotation} from '../image/annotation';
+import {AnnotationGroup} from '../image/annotationGroup';
 import {DrawShapeHandler} from '../tools/drawShapeHandler';
 /* eslint-enable no-unused-vars */
 
diff --git a/src/image/annotation.js b/src/image/annotation.js
index 33f0f306b0..13c004f366 100644
--- a/src/image/annotation.js
+++ b/src/image/annotation.js
@@ -1,5 +1,4 @@
 import {logger} from '../utils/logger';
-import {ListenerHandler} from '../utils/listen';
 import {getFlags, replaceFlags} from '../utils/string';
 import {CircleFactory} from '../tools/circle';
 import {Circle} from '../math/circle';
@@ -224,230 +223,3 @@ export class Annotation {
     return res;
   }
 }
-
-/**
- * Annotation group.
- */
-export class AnnotationGroup {
-  /**
-   * @type {Annotation[]}
-   */
-  #list;
-
-  /**
-   * Annotation meta data.
-   *
-   * @type {Object<string, any>}
-   */
-  #meta = {};
-
-  /**
-   * Listener handler.
-   *
-   * @type {ListenerHandler}
-   */
-  #listenerHandler = new ListenerHandler();
-
-  /**
-   * Editable flag.
-   *
-   * @type {boolean}
-   */
-  #editable;
-
-  /**
-   * @param {Annotation[]} [list] Optional list, will
-   *   create new if not provided.
-   */
-  constructor(list) {
-    if (typeof list !== 'undefined') {
-      this.#list = list;
-    } else {
-      this.#list = [];
-    }
-    this.#editable = true;
-  }
-
-  /**
-   * Get the annotation group as an array.
-   *
-   * @returns {Annotation[]} The array.
-   */
-  getList() {
-    return this.#list;
-  }
-
-  /**
-   * Get the number of annotations of this list.
-   *
-   * @returns {number} The number of annotations.
-   */
-  getLength() {
-    return this.#list.length;
-  }
-
-  /**
-   * Check if the annotation group is editable.
-   *
-   * @returns {boolean} True if editable.
-   */
-  isEditable() {
-    return this.#editable;
-  }
-
-  /**
-   * Set the annotation group editability.
-   *
-   * @param {boolean} flag True to make the annotation group editable.
-   */
-  setEditable(flag) {
-    this.#editable = flag;
-    this.#fireEvent({
-      type: 'annotationgroupeditablechange',
-      data: flag
-    });
-  }
-
-  /**
-   * Add a new annotation.
-   *
-   * @param {Annotation} annotation The annotation to add.
-   */
-  add(annotation) {
-    this.#list.push(annotation);
-    this.#fireEvent({
-      type: 'annotationadd',
-      data: annotation
-    });
-  }
-
-  /**
-   * Update an existing annotation.
-   *
-   * @param {Annotation} annotation The annotation to update.
-   * @param {string[]} [propKeys] Optional properties that got updated.
-   */
-  update(annotation, propKeys) {
-    const index = this.#list.findIndex((item) => item.id === annotation.id);
-    if (index !== -1) {
-      this.#list[index] = annotation;
-      this.#fireEvent({
-        type: 'annotationupdate',
-        data: annotation,
-        keys: propKeys
-      });
-    } else {
-      logger.warn('Cannot find annotation to update');
-    }
-  }
-
-  /**
-   * Remove an annotation.
-   *
-   * @param {string} id The id of the annotation to remove.
-   */
-  remove(id) {
-    const index = this.#list.findIndex((item) => item.id === id);
-    if (index !== -1) {
-      const annotation = this.#list.splice(index, 1)[0];
-      this.#fireEvent({
-        type: 'annotationremove',
-        data: annotation
-      });
-    } else {
-      logger.warn('Cannot find annotation to remove');
-    }
-  }
-
-  /**
-   * Set the associated view controller.
-   *
-   * @param {ViewController} viewController The associated view controller.
-   */
-  setViewController(viewController) {
-    for (const item of this.#list) {
-      item.setViewController(viewController);
-      item.updateQuantification();
-    }
-  }
-
-  /**
-   * Find an annotation.
-   *
-   * @param {string} id The id of the annotation to find.
-   * @returns {Annotation|undefined} The found annotation.
-   */
-  find(id) {
-    return this.#list.find((item) => item.id === id);
-  }
-
-  /**
-   * Get the meta data.
-   *
-   * @returns {Object<string, any>} The meta data.
-   */
-  getMeta() {
-    return this.#meta;
-  }
-
-  /**
-   * Check if this list contains a meta data value.
-   *
-   * @param {string} key The key to check.
-   * @returns {boolean} True if the meta data is present.
-   */
-  hasMeta(key) {
-    return typeof this.#meta[key] !== 'undefined';
-  }
-
-  /**
-   * Get a meta data value.
-   *
-   * @param {string} key The meta data key.
-   * @returns {string|object} The meta data value.
-   */
-  getMetaValue(key) {
-    return this.#meta[key];
-  }
-
-  /**
-   * Set a meta data.
-   *
-   * @param {string} key The meta data key.
-   * @param {string|object} value The value of the meta data.
-   */
-  setMetaValue(key, value) {
-    this.#meta[key] = value;
-  }
-
-  /**
-   * Add an event listener to this class.
-   *
-   * @param {string} type The event type.
-   * @param {Function} callback The function associated with the provided
-   *   event type, will be called with the fired event.
-   */
-  addEventListener(type, callback) {
-    this.#listenerHandler.add(type, callback);
-  }
-
-  /**
-   * Remove an event listener from this class.
-   *
-   * @param {string} type The event type.
-   * @param {Function} callback The function associated with the provided
-   *   event type.
-   */
-  removeEventListener(type, callback) {
-    this.#listenerHandler.remove(type, callback);
-  }
-
-  /**
-   * Fire an event: call all associated listeners with the input event object.
-   *
-   * @param {object} event The event to fire.
-   */
-  #fireEvent = (event) => {
-    this.#listenerHandler.fireEvent(event);
-  };
-}
\ No newline at end of file
diff --git a/src/image/annotationFactory.js b/src/image/annotationFactory.js
index 8882244ce1..66e926d0eb 100644
--- a/src/image/annotationFactory.js
+++ b/src/image/annotationFactory.js
@@ -36,7 +36,8 @@ import {
 } from '../dicom/dicomSpatialCoordinate';
 import {guid} from '../math/stats';
 import {logger} from '../utils/logger';
-import {Annotation, AnnotationGroup} from './annotation';
+import {Annotation} from './annotation';
+import {AnnotationGroup} from './annotationGroup';
 import {Line} from '../math/line';
 import {Point2D} from '../math/point';
 
diff --git a/src/image/annotationGroup.js b/src/image/annotationGroup.js
new file mode 100644
index 0000000000..530381203e
--- /dev/null
+++ b/src/image/annotationGroup.js
@@ -0,0 +1,235 @@
+import {logger} from '../utils/logger';
+import {ListenerHandler} from '../utils/listen';
+
+// doc imports
+/* eslint-disable no-unused-vars */
+import {Annotation} from './annotation';
+import {ViewController} from '../app/viewController';
+/* eslint-enable no-unused-vars */
+
+/**
+ * Annotation group.
+ */
+export class AnnotationGroup {
+  /**
+   * @type {Annotation[]}
+   */
+  #list;
+
+  /**
+   * Annotation meta data.
+   *
+   * @type {Object<string, any>}
+   */
+  #meta = {};
+
+  /**
+   * Listener handler.
+   *
+   * @type {ListenerHandler}
+   */
+  #listenerHandler = new ListenerHandler();
+
+  /**
+   * Editable flag.
+   *
+   * @type {boolean}
+   */
+  #editable;
+
+  /**
+   * @param {Annotation[]} [list] Optional list, will
+   *   create new if not provided.
+   */
+  constructor(list) {
+    if (typeof list !== 'undefined') {
+      this.#list = list;
+    } else {
+      this.#list = [];
+    }
+    this.#editable = true;
+  }
+
+  /**
+   * Get the annotation group as an array.
+   *
+   * @returns {Annotation[]} The array.
+   */
+  getList() {
+    return this.#list;
+  }
+
+  /**
+   * Get the number of annotations of this list.
+   *
+   * @returns {number} The number of annotations.
+   */
+  getLength() {
+    return this.#list.length;
+  }
+
+  /**
+   * Check if the annotation group is editable.
+   *
+   * @returns {boolean} True if editable.
+   */
+  isEditable() {
+    return this.#editable;
+  }
+
+  /**
+   * Set the annotation group editability.
+   *
+   * @param {boolean} flag True to make the annotation group editable.
+   */
+  setEditable(flag) {
+    this.#editable = flag;
+    this.#fireEvent({
+      type: 'annotationgroupeditablechange',
+      data: flag
+    });
+  }
+
+  /**
+   * Add a new annotation.
+   *
+   * @param {Annotation} annotation The annotation to add.
+   */
+  add(annotation) {
+    this.#list.push(annotation);
+    this.#fireEvent({
+      type: 'annotationadd',
+      data: annotation
+    });
+  }
+
+  /**
+   * Update an existing annotation.
+   *
+   * @param {Annotation} annotation The annotation to update.
+   * @param {string[]} [propKeys] Optional properties that got updated.
+   */
+  update(annotation, propKeys) {
+    const index = this.#list.findIndex((item) => item.id === annotation.id);
+    if (index !== -1) {
+      this.#list[index] = annotation;
+      this.#fireEvent({
+        type: 'annotationupdate',
+        data: annotation,
+        keys: propKeys
+      });
+    } else {
+      logger.warn('Cannot find annotation to update');
+    }
+  }
+
+  /**
+   * Remove an annotation.
+   *
+   * @param {string} id The id of the annotation to remove.
+   */
+  remove(id) {
+    const index = this.#list.findIndex((item) => item.id === id);
+    if (index !== -1) {
+      const annotation = this.#list.splice(index, 1)[0];
+      this.#fireEvent({
+        type: 'annotationremove',
+        data: annotation
+      });
+    } else {
+      logger.warn('Cannot find annotation to remove');
+    }
+  }
+
+  /**
+   * Set the associated view controller.
+   *
+   * @param {ViewController} viewController The associated view controller.
+   */
+  setViewController(viewController) {
+    for (const item of this.#list) {
+      item.setViewController(viewController);
+      item.updateQuantification();
+    }
+  }
+
+  /**
+   * Find an annotation.
+   *
+   * @param {string} id The id of the annotation to find.
+   * @returns {Annotation|undefined} The found annotation.
+   */
+  find(id) {
+    return this.#list.find((item) => item.id === id);
+  }
+
+  /**
+   * Get the meta data.
+   *
+   * @returns {Object<string, any>} The meta data.
+   */
+  getMeta() {
+    return this.#meta;
+  }
+
+  /**
+   * Check if this list contains a meta data value.
+   *
+   * @param {string} key The key to check.
+   * @returns {boolean} True if the meta data is present.
+   */
+  hasMeta(key) {
+    return typeof this.#meta[key] !== 'undefined';
+  }
+
+  /**
+   * Get a meta data value.
+   *
+   * @param {string} key The meta data key.
+   * @returns {string|object} The meta data value.
+   */
+  getMetaValue(key) {
+    return this.#meta[key];
+  }
+
+  /**
+   * Set a meta data.
+   *
+   * @param {string} key The meta data key.
+   * @param {string|object} value The value of the meta data.
+   */
+  setMetaValue(key, value) {
+    this.#meta[key] = value;
+  }
+
+  /**
+   * Add an event listener to this class.
+   *
+   * @param {string} type The event type.
+   * @param {Function} callback The function associated with the provided
+   *   event type, will be called with the fired event.
+   */
+  addEventListener(type, callback) {
+    this.#listenerHandler.add(type, callback);
+  }
+
+  /**
+   * Remove an event listener from this class.
+   *
+   * @param {string} type The event type.
+   * @param {Function} callback The function associated with the provided
+   *   event type.
+   */
+  removeEventListener(type, callback) {
+    this.#listenerHandler.remove(type, callback);
+  }
+
+  /**
+   * Fire an event: call all associated listeners with the input event object.
+   *
+   * @param {object} event The event to fire.
+   */
+  #fireEvent = (event) => {
+    this.#listenerHandler.fireEvent(event);
+  };
+}
diff --git a/src/index.js b/src/index.js
index 75c3f9a982..b5e024e3ee 100644
--- a/src/index.js
+++ b/src/index.js
@@ -12,10 +12,8 @@ import {
 import {
   DicomData
 } from './app/dataController';
-import {
-  Annotation,
-  AnnotationGroup
-} from './image/annotation';
+import {Annotation} from './image/annotation';
+import {AnnotationGroup} from './image/annotationGroup';
 import {AnnotationFactory} from './image/annotationFactory';
 import {ViewController} from './app/viewController';
 import {ToolboxController} from './app/toolboxController';