A dosimetric comparison of MammoSite high-dose-rate brachytherapy and Xoft Axxent electronic brachytherapy.
OBJECTIVE
Over 20,000 patients have been treated with partial breast irradiation (PBI) using the MammoSite balloon brachytherapy applicator (IBB). Recently, a new form of balloon-based PBI, Xoft Axxent electronic brachytherapy (KVB), which uses a 50-kV x-ray source, has been introduced. This analysis was undertaken to dosimetrically compare the results of treatment using these two methods of PBI.


METHODS
The study population consisted of 15 patients previously treated with IBB. The planning CT scans from these 15 patients were used to construct hypothetical treatment plans using the source characteristics of the KVB device. The plans were then compared using the dosimetric parameters discussed below.


RESULTS
The mean %V(90) was 99.6% vs. 99.0% (p=nonsignificant [ns]), the mean %V(100) was 96.5% vs. 96.5%, the mean %V(150) was 41.8% vs. 59.4% (p<0.05), the mean %V(200) was 11.3% vs. 32.0% (p<0.05), and the mean %V(300) was 0.4% vs. 6.7% (p<0.05) for the IBB and KVB methods, respectively. The mean ipsilateral breast %V(50) was 19.8% vs. 13.0% (p<0.05), the mean ipsilateral lung %V(30) was 3.7% vs. 1.1% (p<0.05), and the mean heart %V(5) was 59.2% vs. 9.4% (p<0.05) for the IBB and KVB methods, respectively.


CONCLUSIONS
The IBB and KVB methods of PBI offer comparable target volume coverage; however, the KVB method is associated with an increased volume of breast tissue in the high-dose regions and a decreased dose to the adjacent normal tissues.
Dickler
Adam
A
Department of Radiation Oncology, Rush University Medical Center, Chicago, IL 60612, USA. atd22_99@yahoo.com
Kirk
Michael C
MC
Seif
Neil
N
Griem
Katherine
K
Dowlatshahi
Kambiz
K
Francescatti
Darius
D
Abrams
Ross A
RA
D001918:Brachytherapy / Q000295:instrumentation / Q000379:methods*; D001940:Breast / Q000528:radiation effects; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D004307:Dose-Response Relationship, Radiation; D004581:Electronics; D005260:Female; D006321:Heart / Q000528:radiation effects; D017619:Hemibody Irradiation / Q000295:instrumentation / Q000379:methods; D006801:Humans; D007496:Iridium Radioisotopes / Q000627:therapeutic use; D008168:Lung / Q000528:radiation effects; D011874:Radiometry; D011879:Radiotherapy Dosage; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden / Q000528:radiation effects
D007496:Iridium Radioisotopes