2.3 125I RSI-BT
All patients underwent standard RSI-BT procedure (Fig 1). Pre-operative
CT scans (slice thickness 2.5-5 mm with contrast) was carried out and
images were transmitted to Brachytherapy Treatment Planning System
(BT-TPS) (Beijing Astro Technology, Beijing, China). The needle-puncture
pathway was designed on BT-TPS. Radioactivity and number of seeds were
calculated according to prescription doses (PD) design. Individualized
template was made by three-dimensional-printing techniques (3D-PT).
Finally, a digital information of needles channels on BT-TPS for
pre-operative plan was transferred into 3D-pinting software and
reconstruction.
Patients were usually positioned supine according to the tumor sites.
After the induction of local anesthesia, the operator chose the best
layer and angle for needle puncture assisted or not by 3D-PT based on
the pre-operative plan and followed by needle insertion. CT scans to
verify the needles position and direction, the operator optimized the
angle and depth of the needle by real-time CT scan to conform the
pre-operative plan. Then, seeds were implanted using a
Mick® Applicator (Mick Radio Nuclear Instruments,
Mount Vernon, NY, USA) according to pre-plan. Finally, CT was undertaken
immediately following seeds implantation to check the actual
distribution of 125I seeds and, if necessary, more seeds would be
implanted for doses distribution in the targets as pre-plan
requirements.