Brachytherapy procedure

Iodine-125 seeds were implanted into brain metastases under the guidance of a 1.0-T open MR and three-dimensional template. The template was placed on the scalp coinciding with reference points. The position of the template was confirmed by enhanced MR images of T1-weighted turbo spin echo (T1W-TSE). Patient was then moved outside of the magnet bore, and lidocaine for local anesthesia and diazepam for intravenous conscious sedation were administered. Twist-drill holes were made in the skull through the drilling template using a battery-operated twist drill (Figure 3A). Then, needles with blunt tip were inserted into the tumor to pre-determined depths through the template (Figure 3B). The patient was moved back into the magnet bore and underwent MR scanning to visualize the position of needles (Figure 4). Iodine-125 seeds were implanted into the tumor following the pre-operative brachytherapy treatment plan.

3D template-guided ¹²⁵I brachytherapy for brain metastasis. A) Twist-drill holes were made through the drilling template. B) Needles with blunt tip were inserted into the tumor through the puncturing template

Needles were punctured into the tumor through 3D template. A, B) The positions of needles were displayed by transverse and coronal MR images. C) Intra-operative T1W gradient echo (T1W-FFE) images showed hypo-intense ¹²⁵I seeds