Brachytherapy, also known as internal radiotherapy, is a form of radiotherapy where a radiation source is placed inside or next to the area requiring treatment. Brachytherapy is commonly used as an effective treatment for cervical, prostate, breast, and skin cancer and can also be used to treat tumours in many other body sites. Brachytherapy can be used alone or in combination with other therapies such as surgery and chemotherapy. This book presents current research from around the globe in the study of brachytherapy including High Dose Rate (HDR) Intracavitary Brachytherapy for cervical, breast and prostate cancer, as well as nanobrachytherapy and Brachytherapy for soft tissue sarcomas.