Technical Innovations in the Delivery of Radiation Therapy

Radiation oncology is a technology-driven field quickly adopting technical innovations to improve treatment outcomes. A few months after Rӧntgen’s discovery of X-rays, therapeutic X-ray use was proposed and applied to treat cancer. Since knowledge of the biological effects of radiation increases with better capabilities to control radiation delivery, therapeutic techniques continually evolve as radiotherapy incorporates new technologies. This chapter describes innovations implemented in the current generation of radiotherapy machines. Significant improvements for imaging patients in the treatment room using computed tomography, magnetic resonance imaging, and optical or infrared surface detection combined with more precise radiation delivery are altering practice patterns. The current delivery systems enable treatment regimens having higher doses per fraction and fewer fractions with similar or better outcomes than previous generation machines. Patients’ internal and external anatomies are monitored during radiation delivery. Any changes in patient’s anatomy or tumor position in excess of pre-established parameters will trigger an automatic stoppage of the radiation delivery system by computer control through analysis of imaging data. Emerging technologies showing promise in preclinical and early clinical studies, including automated real-time treatment delivery to biologically functional regions identified by positron-emission tomography, combining radiotherapy with immunotherapy to treat local and metastatic disease, and ultrafast delivery of radiation at dose rates orders of magnitude greater than currently practiced, are described.