"What goes round comes round"

Soon after the discovery of x-rays by Roentgen, radioactivity by Becquerel, and radium by the Curies, it was concluded that x-rays could not only be used for diagnostic purposes but also for therapy [1,2]. In the early years of radiation therapy, physicians had little understanding or knowledge of the physical nature and biological effects of radiation, the delivered doses were not certain, the equipment was not just primitive and temperamental but limited in energy output and as such was associated with high failure rates, numerous tumour recurrences and complications. Radiotherapy today has come a long way and has become an essential tool in the treatment of cancer and other diseases along with surgery, chemotherapy, image guided interventions, and targeted radionuclide therapy [3]. In addition, newer biological therapies (immunotherapy, biotherapy, or biological response modifier therapy) are fast becoming part of the widened armamentarium [4]. This special focused issue of biij will cover some of these topics. From a common origin based on x-rays, the diagnostic and therapeutic aspects diverged over the last 110 years or so. The early practitioners of radiation therapy and diagnostic radiology began as members of other specialties. Dermatologists and surgeons comprised significant numbers of these early radiation pioneers with even a greater percentage coming from the “field” of electrotherapy. If one reviews some of the early monographs, the titles illustrate the close connection between the two fields of radiation therapy and diagnostic radiology [5,6]. But we seem to have come full circle with the increasing convergence between the therapy and diagnostic aspects with increasingly role of