Author(s): Borghero YO, Salehpour M, McNeese MD, Stovall M, Smith SA,
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Abstract PURPOSE: Static multileaf collimated field-in-field forward-planned intensity-modulated radiation treatment (FiF-IMRT) has been shown to improve dose homogeneity compared to conventional wedged fields. However, a direct comparison of the scattered dose to the contralateral breast resulting from wedged and FiF-IMRT plans remains to be documented. METHODS: The contralateral scattered breast dose was measured in a custom-designed anthropomorphic breast phantom in which 108 thermoluminescent dosimeters (TLDs) were volumetrically placed every 1-2cm. The target phantom breast was treated to a dose of 50Gy using three dose compensation techniques: No medial wedge and a 30-degree lateral wedge (M0-L30), 15-degree lateral and medial wedges (M15-L15), and FiF-IMRT. TLD measurements were compared using analysis of variance. RESULTS: For FiF-IMRT, the mean doses to the medial and lateral quadrants of the contralateral breast were 112cGy (range 65-226cGy) and 40cGy (range 18-91 cGy), respectively. The contralateral breast doses with FiF-IMRT were on average 65\% and 82\% of the doses obtained with the M15-L15 and M0-L30 techniques, respectively (p<0.001). Compared to the M15-L15 technique, the maximum dose reduction obtained with FiF-IMRT was 115cGy (range 13-115cGy). CONCLUSIONS: The dose to the contralateral breast is significantly reduced with FiF-IMRT compared to wedge-compensated techniques. Although long-term follow-up is needed to establish the clinical relevance of this finding, these results, along with the previously reported improvement in ipsilateral dose homogeneity, support the use of FiF-IMRT if resources permit.
This article was published in Radiother Oncol
and referenced in Atherosclerosis: Open Access