CT-Guided Fiducial Marker Implantation with Ultra-fine 25-Gauge Needle Prior to Proton Therapy for Liver Malignancies

Purpose Proton therapy is highly effective for liver malignancies, and to increase its accuracy, placement of fiducial markers in the liver is preferred. We retrospectively evaluated the safety and feasibility of CT-guided fiducial marker implantation using ultra-fine 25-gauge needles before proton therapy for liver malignancies. Materials and Methods Between May 2016 and April 2021, 334 cases were investigated. All of procedures were performed without anesthesia. Technical success was defined as the completion of implantation at the intended site. Tumor–marker distance and possibility of synchronization between tumors and markers were evaluated and compared with Mann–Whitney U test. Complications were evaluated using the Common Terminology Criteria for Adverse Events, version 4.0. Results Technical success rate was 97.3%. Tumor–marker distance was 19.1 mm (median, range 0–96) in the group in which the implanted marker was synchronized with tumor (n = 315), while it was 34.5 mm (median, range 6–94) in the group in which the implanted marker was not synchronized (n = 13) ( p value = 0.011