Medical imaging that uses ionizing radiation, such as CT, radiography, nuclear medicine, and fluoroscopy, is a cornerstone of the care of oncology patients and provides great benefit. Ionizing radiation at high doses is a known carcinogen.The exact degree of the risk of carcinogenesis from the lower doses of ionizing radiation used in medical imaging is less clear. The purpose of this review is to provide the oncology community with knowledge about the doses used in medical imaging, radiation-induced cancer risks from imaging, considerations to keep in mind when balancing imaging benefits and risks in pediatric and adult oncologic settings, dose reduction strategies, and the "Image Gently" and "Image Wisely" campaigns; the latter campaigns facilitate the translation of existing evidence into best practices for providers and patients.