Introduction to special issue on datasets hosted in The Cancer Imaging Archive (TCIA). - Kirby, Justin; Prior, Fred; Petrick, Nicholas; Hadjiski, Lubomir; Farahani, Keyvan; Drukker, Karen; Kalpathy‐Cramer, Jayashree; Glide‐Hurst, Carri; El Naqa, Issam (Medical Physics, 2020)