Emergency localization of radioactive seeds lost during intracoronary brachytherapy.

Recently, it has been reported that brachytherapy catheters ruptured in vivo. Localization of lost beta-radiation-emitting seeds is a problem because no appropriate technique is available that is rapid and precise. We developed a technique to localize beta-emitting seeds utilizing the effect that beta-radiation induces bremsstrahlung. The loss of a single radioactive source was simulated in an Alderson Phantom representing a human body. The beta-induced bremsstrahlung could be detected selectively by a gamma-camera. The position of the radioactive seed could be located within 5 min with an accuracy of +/- 0.5 cm. The result of this study suggests that in an emergency case of loss of a brachytherapy source, a commercially available gamma-camera can be a valuable tool to detect lost beta-radiation-emitting seeds rapidly and precisely. In addition, the technique minimizes the patient's as well as the surgeon's exposure to radiation and reduces the extent of surgical trauma.