AbstractID: 9199 Title: The Integral Doses in the Intravascular Brachytherapy
Intravascular Brachytherapy (IVB) is the use of temporary (catheter based) irradiation
with PTA to prevent restenosis in vascular structures. The source in IVB provides
uniform dose along the source wire with dose drop off at the edges. The purpose of this
study is to investigate non-target integral doses in IVB with or without a centering
catheter.
The current devices used for IVB are the Novoste and the Galileo systems. There are 12
90
Sr seeds, each 2.5 mm long, in the Novoste system without a centering catheter. The
Galileo system has a 27mm long 32P source with a centering catheter. The prescription
dose is 18.4 Gy at 2 mm in water for the Novoste system and 20 Gy at 1mm beyond the
RLD(reference lumen diameter) for the Galileo system. We sought to investigate the
integral doses of 3 non-target volumes, the radial distance from the source axis at
3.18mm, 6.18mm, and 11.18 mm.
The integral doses for these 3 volumes were 205 cGy, 304 cGy, and 328 cGy when the
source was in the center of the artery. However, the integral doses for the non-centered
source were 1300 cGy, 330 cGy, and 337 cGy. The results show that non-centered
catheter will deliver doses to the non-target volume which are 634%, 8.5% and 3% higher
than the centered catheter at distances of 3.18, 6.18 and 11.18mm, respectively.
It is important that the source is in the center of artery when there is concern for dose to
non-target volumes at <1cm.