William Wegman is best known for the enchanting photos of his Weimaraner dogs. On Jan. 29, he was at the Georgetown Lombardi Comprehensive Cancer Center where he read to patients, signed his latest book, “Flo & Wendell Explore,” and donated five of his works in honor of his colleague Emily Heick, a breast cancer survivor. The reception hailed Julia Langley, who launched the Arts and Humanities Program.