Multicatheter hybrid breast brachytherapy: a potential alternative for patients with inadequate skin distance.
OBJECTIVE
The purpose of this study was to determine whether the ClearPath (CP) multicatheter hybrid device was able to achieve acceptable dosimetry in patients in whom the proximity of the breast surgical cavity to the skin precluded treatment with intracavitary MammoSite (MS) brachytherapy.


METHODS
The study consisted of 11 patients who had the MS catheter placed and who were subsequently not treated due to inadequate skin distance. A phantom scan of the CP multicatheter hybrid device was superimposed on the MS CT scan and a dosimetric comparison was performed.


RESULTS
The median MS balloon size, diameter, and minimum skin distance were 40 cc, 4.1cm, and 5mm, respectively. The D(90), V(100), V(150), and V(200) with MS vs. CP were 95.29% vs. 97.06%, 88.8% vs. 91.3%, 35.7% vs. 38.0%, and 9.4% vs. 9.6%, respectively. The median maximum skin dose was 5.5 Gy vs. 3.9 Gy (p <.0001). The median dose homogeneity index (DHI) was 0.60 vs. 0.59 (p=.09). The median maximum rib, heart, and lung dose were 2.17 Gy vs. 2.18 Gy, 2.17 Gy vs. 2.18 Gy, and 0.50 Gy vs. 0.56 Gy, respectively.


CONCLUSIONS
The hybrid CP catheter reduced the skin dose significantly without compromising the planning target volume coverage, DHI, or dose to other critical organs. The use of this device has the potential to increase the applicability of accelerated partial breast brachytherapy (APBI) in patients with a surgical cavity close to skin compared with balloon brachytherapy.
Beriwal
Sushil
S
Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA. beriwals@upmc.edu
Coon
Devin
D
Kim
Hayeon
H
Haley
Marsha
M
Patel
Rakesh
R
Das
Rupak
R
D001918:Brachytherapy / Q000295:instrumentation*; D001940:Breast / Q000033:anatomy & histology / Q000528:radiation effects; D001943:Breast Neoplasms / Q000532:radiotherapy*; D015331:Cohort Studies; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D011879:Radiotherapy Dosage