Colorectal cancer is a leading cause of cancer morbidity and mortality in the United States. CT colonography, frequently referred to as "virtual colonoscopy," plays an increasingly important role in the screening and characterization of colorectal cancer, as well as the surveillance of suspicious polyps and post-treatment monitoring. This article describes the epidemiology, pathobiology, diagnosis, and treatment of colorectal cancer, and the roles of CT colonography and other imaging modalities in screening, surveillance, staging, and post-treatment monitoring. CT colonography techniques, including patient preparation, fecal tagging, colon insufflation (inflation), and the emerging technology of computer-aided detection also are covered.

Breast implants are classified as medical devices because they are used to correct the size or shape of a woman's natural breast or to create a new breast after mastectomy. Breast augmentation is the most popular cosmetic surgery performed in the United States today. Over the decades, breast implants have been constructed using different types of materials, including sponges, silicone, and saline. Each type of implant has advantages and disadvantages, and all pose a challenge in breast imaging. Breast implant rupture is common and has hidden characteristics that pose challenges for radiologic technologists and physicians. This article provides detailed information on breast reconstruction, implant safety, imaging techniques, and the latest implant materials.