Program Information
HDR Afterloader Brachytherapy Treating Very Long, Thin Targets in Patients with Peripheral Atherosclerotic Vascular Disease Following Percutaneous Transluminal Angioplasty
TC Harris1*, IM Buzurovic2 , MS Bhagwat3 , DA O'Farrell4 , SA Friesen5 , JL Hansen6 , RA Cormack7 , PM Devlin8 , (1) Brigham & Women's Hospital, Boston, MA, (2) Brigham & Women's Hospital, Harvard Medial School, Boston, MA, (3) Dana Farber/Brigham and Women's Hospital, Boston, MA, (4) Dana Farber Cancer Institute, Boston, MA, (5) Brigham & Women's Hospital,Boston, MA, (6) Brigham & Women's Hospital, Boston, MA, (7) Brigham and Women's Hospital, Boston, MA, (8) Brigham & Women's Hospital, Boston, MA
Presentations
SU-I-GPD-T-19 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: Percutaneous angioplasty for atherosclerotic plaques associated with peripheral vascular disease is often complicated by restenosis requiring repeat interventions. Radiation therapy to peripheral vessels may lower the risk of restenosis but involves considerations distinct from standard coronary vascular irradiation protocols. Specifically, due to the larger diameter of peripheral vs. coronary vessels (~7-10mm vs. ~3mm), a β source may underdose subintimal walls, necessitating a high energy γ source such as Ir-192. Restenosis lesions are often longer and multifocal in peripheral vessels. Therefore, irradiation via HDR afterloader may be more effective in treating very long, thin targets.
Methods: Immediately following angioplasty, the radiation oncologist confirms the treatment region with an radiologist who places an HDR catheter, adding a 2cm margin to distal and proximal region in order to prevent a miss at the edge. The written directive should contain: treatment length, offset from the end of the catheter, treatment distance, and prescription dose. Treatment planning can be accomplished with no dwell time optimization used; because of the long treatment length, tapering at the ends is small and restricted to the added margin. When the treatment length exceeds the maximum number of dwell positions per channel, it is critical to generate an additional plan with an appropriate offset such that there is no overlap and no gap. Treatment resembles a typical HDR session. Prior to attaching the catheter to the afterloader, the physicist attaches a source simulator and manually verifies that the catheter is free of obstruction.
Results: Our department’s peripheral vascular irradiation procedure using an Ir-192 source and Elekta MicroSelectron afterloader has been conducted in 110 patients in the past 18 months (treatment lengths = 10-70cm).
Conclusion: Planning and treatment of peripheral vascular irradiation cases can be implemented safely at any institution with an HDR afterloader and an interventional radiology suite.
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