Magnetic resonance imaging following interstitial implantation of pelvic malignancies

The purpose of this study was to develop a magnetic resonance imaging (MRI) technique that will permit artifact‐free visualization of implanted needles in relation to tumor volume and normal internal anatomy for treatment planning after interstitial implantation of pelvic malignancies. Development of an MRI‐compatible template and needle system is described in two patients. The system consists of a modified plastic Syed‐Neblett template and vaginal obturator with sleeve accommodating plastic flexiguides loaded with titanium obturators. Visualization of the flexiguides loaded with titanium obturators and their relationship to normal structures and tumor volume were assessed following MRI scanning. The images obtained reveal no scatter artifact from the flexiguides. It was possible to distinguish the flexiguides from the soft tissues and evaluate their relationship to tumor and normal internal anatomy. In conclusion, MRI following trans‐perineal interstitial implantation of pelvic malignancies is possible and may ultimately be superior to computed tomography (CT) in defining the relationship of the needles to tumor volume as well as the normal internal structures. Further work will determine the optimum techniques for MRI‐based dosimetric analysis of transperineal interstitial implantation of pelvic malignancies. © 1995 Wiley‐Liss, Inc.