A dosimetric comparison of MammoSite® and ClearPath high-dose-rate breast brachytherapy devices

PURPOSE: A new form of partial breast irradiation (PBI), ClearPath (CP) breast brachytherapy, has been introduced. We present our results of a dosimetric comparison of MammoSite (R) (MS) and CP PBI. METHODS AND MATERIALS: The dimensions of the CP device were reconstructed onto the MS planning CT scans for 15 previously treated patients. The mean %V-100, %V-150, %V-200 (percent of the PTV that received 100%, 150%, and 200% of the prescription dose, respectively), ipsilateral breast %V-50 (percent of the ipsilateral normal breast that received 50% of the prescription dose), ipsilateral lung %V-30 (percent of the ipsilateral lung that received 30% of the prescription dose), the heart %V-30 (percent of the heart that received 5% of the prescription dose), and the maximum skin point dose per fraction were then determined for each patient using the two methods of balloon-based PBI. RESULTS: The mean %V100 was 96.5% vs. 96.5%, the mean %V150 was 42.1% vs. 42.9% (p = ns), and the mean V-200 was 11.4% vs. 15.2% (p < .05) for the MS and CP methods, respectively. The mean ipsilateral breast %V-50 was 19.8% vs. 18.0% (p < .05). the mean ipsilateral lung %V-30 was 3.7% vs. 2.8% (p < .05), the mean heart %V-5 was 57.0% vs. 54.3% (p <.05), and the maximum skin point dose per fraction was 312.2 and 273.6 cGy (p <.05) for the MS and CP methods, respectively. CONCLUSIONS: The MS and CP methods of PBI offer comparable target volume coverage: however. the CP device achieves increased normal tissue sparing. (c) 2009 Published by Elsevier Inc on behalf of American Brachytherapy Society.