MR-aided brachytherapy of nonresectable liver metastases - preliminary technical and clinical experience

Purpose. To evaluate the feasibility and efficacy of MR-guided interstitial brachytherapy of non-resectable liver metastasis. Methods. Liver metastases (0.8-5.2 cm in diameter) were treated during a pr ospective phase I/II study using an open 0.2 Tesla MR system (Magnetom Open Viva, Siemens, Erlangen). MR-compatible brachytherapy applicators were pla ced percutaneously under MR-guidance in an open 0,2 Tesla MR system (Magnet om Open Viva,Siemens, Erlangen) using fast T1-weighted sequences. Pretreatm ent and follow-up studies were performed using a 1.5 Tesla MR system. Results. Preliminary results of an unpublished prospective study are discus sed exemplary on 2 selected patients. The median procedure time was 4.9 h. No major complications were observed and late effects were acceptable. In l arge symptomatic metastases only a temporary relief of pain was achieved. I n smaller metastases (DM 3 cm) a tumor control was observed. Conclusion. MR-guided brachytherapy is feasible and has the potential to ab late liver metastases with diameter of less than 3 cm. Further developments are necessary.