The impact of dose calculation algorithms on partial and whole breast radiation treatment plans
Date
2010-12-16
Authors
Basran, Parminder S.
Zavgorodni, Sergei
Berrang, Tanya
Olivotto, Ivo A.
Beckham, Wayne
Journal Title
Journal ISSN
Volume Title
Publisher
BioMed Central
Abstract
Background: This paper compares the calculated dose to target and normal tissues when using pencil beam
(PBC), superposition/convolution (AAA) and Monte Carlo (MC) algorithms for whole breast (WBI) and accelerated
partial breast irradiation (APBI) treatment plans.
Methods: Plans for 10 patients who met all dosimetry constraints on a prospective APBI protocol when using PBC
calculations were recomputed with AAA and MC, keeping the monitor units and beam angles fixed. Similar
calculations were performed for WBI plans on the same patients. Doses to target and normal tissue volumes were
tested for significance using the paired Student’s t-test.
Results: For WBI plans the average dose to target volumes when using PBC calculations was not significantly
different than AAA calculations, the average PBC dose to the ipsilateral breast was 10.5% higher than the AAA
calculations and the average MC dose to the ipsilateral breast was 11.8% lower than the PBC calculations. For ABPI
plans there were no differences in dose to the planning target volume, ipsilateral breast, heart, ipsilateral lung, or
contra-lateral lung. Although not significant, the maximum PBC dose to the contra-lateral breast was 1.9% higher
than AAA and the PBC dose to the clinical target volume was 2.1% higher than AAA. When WBI technique is
switched to APBI, there was significant reduction in dose to the ipsilateral breast when using PBC, a significant
reduction in dose to the ipsilateral lung when using AAA, and a significant reduction in dose to the ipsilateral
breast and lung and contra-lateral lung when using MC.
Conclusions: There is very good agreement between PBC, AAA and MC for all target and most normal tissues
when treating with APBI and WBI and most of the differences in doses to target and normal tissues are not
clinically significant. However, a commonly used dosimetry constraint, as recommended by the ASTRO consensus
document for APBI, that no point in the contra-lateral breast volume should receive >3% of the prescribed dose
needs to be relaxed to >5%.
Description
BioMed Central
Keywords
Citation
Basran et al.: The impact of dose calculation algorithms on partial and whole breast radiation treatment plans. Radiation Oncology 2010 5:120.