Dosimetric comparison of Volumetric Modulated Arc Therapy and Three Dimensional Conformal Radiotherapy during Post Mastectomy left chest wall Irradiation

Abstract

Arpitha S Rao, Swathi S Amin, S Sowmya Narayanan and Geeta S Narayanan

Aims: To dosimetrically evaluate the Volumetric Modulated Arc Therapy (VMAT) technique and compare it with Three-Dimensional Conformal Radiotherapy (3D-CRT) for postmastectomy breast cancer therapy.

Methods and Material: Ten consecutively treated left sided breast cancer patients were selected for this study. VMAT plans were generated from each of the patients planning CT and compared with 3D-CRT plans.

Statistical analysis used: Two tailed paired t test

Results: The VMAT technique provided statistically significant homogenous and conformal dose distribution with mean HI of (0.1±0.02) and mean CI of (1.1±0.06) when compared mean HI of (0.3±0.02) and mean CI of (1.7±0.2) in the 3D-CRT technique. VMAT plans showed reduced V30 of the heart (10±4.54) when compared to 3D-CRT plans (15.1±8.53). Except V30, VMAT plans resulted in higher doses to heart. The mean doses received by left lung was (17.50±6.27) and was significantly higher than that of 3D-CRT plans (10.20±3.72). VMAT plans also gave higher doses to the contralateral lung and the opposite breast.

Conclusions: VMAT plans in post mastectomy breast cancers provide more homogenous and conformal plans as compared to 3DCRT plans but higher doses to normal tissues.

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