Design and Fabrication of MR-Tracked Metallic Stylet for Gynecologic Brachytherapy

Active magnetic resonance (MR) tracking for gynecologic brachytherapy was made possible by attaching the microradiofrequency coils to the brachytherapy applicator. The rectangular planar microcoil was fabricated using flexible printed circuits with dimensions of 8 mm × 1.5 mm. A 5-Fr (1.6 mm) tungsten brachytherapy stylet was custom-machined to incorporate the microcoils. The finite element analysis and the phantom tissue studies show that the proposed device enables in situ real-time guidance of access routes to the target anatomy safely and accurately. The setup was tested in a Siemens 3T MR scanner. The microcoils can be localized rapidly (up to 40 Hz) and precisely (resolution: 0.6 mm × 0.6 mm × 0.6 mm) using an MR-tracking sequence.