REF: Remove unused variable in PET notebook

Remove unused variable in PET notebook: left behind in commit 0357331.

Author: jhlegarreta

docs/notebooks/pet_motion_estimation.ipynb

@@ -2428,11 +2428,10 @@
    ]
   },
   {
-   "cell_type": "code",
-   "execution_count": 16,
-   "id": "f4bf7ccc-2b80-4792-8379-408c3c65b4c3",
    "metadata": {},
+   "cell_type": "code",
    "outputs": [],
+   "execution_count": null,
    "source": [
     "import numpy as np\n",
     "import pandas as pd\n",
@@ -2447,38 +2446,15 @@
     "    motion_parameters.append([tx, ty, tz, rx, ry, rz])\n",
     "\n",
     "motion_parameters = np.array(motion_parameters)\n",
-    "estimated_fd = compute_fd_from_motion(motion_parameters)\n",
-    "\n",
-    "# Creating a DataFrame for better visualization\n",
-    "df_motion = pd.DataFrame(\n",
-    "    {\n",
-    "        \"Frame\": np.arange(len(estimated_fd)),\n",
-    "        \"Translation X\": motion_parameters[:, 0],\n",
-    "        \"Translation Y\": motion_parameters[:, 1],\n",
-    "        \"Translation Z\": motion_parameters[:, 2],\n",
-    "        \"Rotation X\": motion_parameters[:, 3],\n",
-    "        \"Rotation Y\": motion_parameters[:, 4],\n",
-    "        \"Rotation Z\": motion_parameters[:, 5],\n",
-    "        \"Framewise Displacement (mm)\": estimated_fd,\n",
-    "    }\n",
-    ")"
-   ]
+    "estimated_fd = compute_fd_from_motion(motion_parameters)"
+   ],
+   "id": "d3627d44376b27f4"
   },
   {
-   "cell_type": "code",
-   "execution_count": 19,
-   "id": "92cceeda-6e40-4cdc-9129-5ffce477af84",
    "metadata": {},
-   "outputs": [
-    {
-     "name": "stderr",
-     "output_type": "stream",
-     "text": [
-      "/var/folders/0d/tx6_gy7951749z57rjjkkl_m0000gn/T/ipykernel_5538/1383021636.py:33: UserWarning: FigureCanvasAgg is non-interactive, and thus cannot be shown\n",
-      "  plt.show()\n"
-     ]
-    }
-   ],
+   "cell_type": "code",
+   "outputs": [],
+   "execution_count": null,
    "source": [
     "# Set up the matplotlib figure\n",
     "import matplotlib.pyplot as plt\n",
@@ -2490,7 +2466,8 @@
     "plot_volumewise_motion(np.arange(len(fd)), motion_parameters)\n",
     "\n",
     "plt.show()"
-   ]
+   ],
+   "id": "4f141ebdb1643673"
   },
   {
    "metadata": {},