Abstract

The aim of the study is to compare dosimetry of 3DCRT versus VMAT in post mastectomy left sided carcinoma breast patient. The plan was created using a mono-isocentric technique. The chest wall was irradiated using two opposing tangential beams in 3DCRT technique. A single anterior field with an angle of 10° away from the spinal cord was used to treat the SCF and axillary apex. Dose prescription was done to isocentre. To ensure adequate PTV coverage and reduce hotspot to less than 107%, the Field-in-Field technique with MLCs was used with multiple subfields. The dynamic weightings used in this study were chosen to maximize PTV dose coverage and homogeneity. The prescription was given at the point for the nodal dose but was normalized to reduce hotspots to less than 107% isodose line. The algorithm used was Collapsed Cone and 6 MV photons with a dose rate of 600 MU/min were used for the chest wall, whereas 10MV energy was used for nodal areas. Conclusion: VMAT better than the standard method as far dosimetry of high dose volumes was considered. Inverse planning methods that worsened performance were the low dose irradiation of the heart, lung, contralateral breast, and integral dose to the body. It would be prudent to conclude that VMAT was superior to 3DCRT if only target volume and high dose irradiation were prioritized but worse when low dose irradiation was brought into the picture

Description

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