Comparison of Dose Distributions With TG-43 and Collapsed Cone Convolution Algorithms Applied to Accelerated Partial Breast Irradiation Patient Plans.
To compare the treatment plans for accelerated partial breast irradiation calculated by the new commercially available collapsed cone convolution (CCC) and current standard TG-43-based algorithms for 50 patients treated at our institution with either a Strut-Adjusted Volume Implant (SAVI) or Contura device.



We recalculated target coverage, volume of highly dosed normal tissue, and dose to organs at risk (ribs, skin, and lung) with each algorithm. For 1 case an artificial air pocket was added to simulate 10% nonconformance. We performed a Wilcoxon signed rank test to determine the median differences in the clinical indices V90, V95, V100, V150, V200, and highest-dosed 0.1 cm(3) and 1.0 cm(3) of rib, skin, and lung between the two algorithms.



The CCC algorithm calculated lower values on average for all dose-volume histogram parameters. Across the entire patient cohort, the median difference in the clinical indices calculated by the 2 algorithms was <10% for dose to organs at risk, <5% for target volume coverage (V90, V95, and V100), and <4 cm(3) for dose to normal breast tissue (V150 and V200). No discernable difference was seen in the nonconformance case.



We found that on average over our patient population CCC calculated (<10%) lower doses than TG-43. These results should inform clinicians as they prepare for the transition to heterogeneous dose calculation algorithms and determine whether clinical tolerance limits warrant modification.
The University of Texas Graduate School of Biomedical Sciences at Houston, The University of Texas MD Anderson Cancer Center, Houston, Texas. Electronic address: slloupot@mdanderson.org.
Sara L
SL
Thrower
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Simona F
SF
Shaitelman
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Elizabeth
E
Bloom
Department of Radiation Physics, The University of Texas Graduate School of Biomedical Sciences at Houston, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Mohammad
M
Salehpour
Department of Radiation Physics, The University of Texas Graduate School of Biomedical Sciences at Houston, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Kent
K
Gifford
D000465:Algorithms; D001918:Brachytherapy / Q000379:methods*; D001943:Breast Neoplasms / Q000503:physiopathology / Q000532:radiotherapy*; D003198:Computer Simulation; D005260:Female; D006801:Humans; D015233:Models, Statistical; D058958:Organs at Risk / Q000528:radiation effects; D000069473:Radiation Dose Hypofractionation; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D016896:Treatment Outcome