add nlst_exploration to the list

Author: fedorov

README.md

@@ -46,6 +46,7 @@ This folders contains notebooks that demonstrate the usage of the data in the sp
 * [Using hiplot for exploring prostate MRI in IDC](https://github.com/ImagingDataCommons/IDC-Tutorials/blob/master/notebooks/collections_demos/prostate-MRI_hiplot_experiments.ipynb): this notebook demonstrates how [`hiplot`](https://facebookresearch.github.io/hiplot/), an open source package for high-dimensional parameter visualization, for examining various MRI acquisition parameters for the prostate MRI images available in IDC.
 * [Visible Human Project exploration](https://github.com/ImagingDataCommons/IDC-Tutorials/blob/master/notebooks/collections_demos/nlm_visible_human_project.ipynb): demonstration of searching and visualizing images from the National Library of Medicine Visible Human Project available on IDC.
 * [RMS-Mutation-Prediction collection exploration](https://github.com/ImagingDataCommons/IDC-Tutorials/tree/master/notebooks/collections_demos/rms_mutation_prediction): notebooks in this folder demonstrate selecting images from the `RMS-Mutation-Prediction` collection based on various attributes of images and expert annotations.
+* [NLST collection exploration](https://github.com/ImagingDataCommons/IDC-Tutorials/blob/master/notebooks/collections_demos/nlst_exploration.ipynb): explanation of the content included in the IDC NLST collection, and how it is different from the NLST collection you will find in TCIA.
 
 ## [`pathomics`](https://github.com/ImagingDataCommons/IDC-Tutorials/tree/master/notebooks/pathomics)