Lessons learned in radiology

The paper reviews aspects of the history of radiology with the goal of identifying lessons learned, particularly in the area of radiological protection of the patient in diagnostic and interventional radiology, nuclear medicine and radiotherapy. It is pointed out that since the days of Roentgen there has been a need not only to control and quantify the amount of radiation reaching the patient but also to optimize the imaging process to offer the greatest diagnostic benefit within allowable levels of patient dose. To this end, in diagnostic radiology, one finds the development of better films, X rays tubes, grids, screens and processing techniques, while in fluoroscopy, one sees the increased luminance of calcium tungstate. In interventional radiology, one finds an improvement in catheterization techniques and contrast agents. In nuclear medicine, the development of tracer techniques into modern cameras and isotopes such as technetium can be followed. In radiotherapy, one sees the early superficial X rays and radium sources gradually replaced with radon seeds, supervoltage, 60Co and today's linear accelerators. Along with the incredible advances in imaging and therapeutic technologies comes the growing realization of the potential danger of radiation and the need to protect the patient (as well as physicians, ancillary personnel and the general population) from unnecessary radiation. The important lesson learned is that we must walk a tightrope, balancing the benefits and risks of any technology utilizing radiation to produce the greatest benefits at the lowest acceptable risk. The alternative techniques using non-ionizing radiation will have to be considered as part of the general armamentarium for medical imaging whenever radiation consequences are unacceptable. (author)