Comparison of radiotherapy treatment plans for left-sided breast cancer patients based on three- and four-dimensional computed tomography imaging

Aims: The target volume for breast radiotherapy after conservative surgery for breast cancer may be affected by breathing motion. We investigated differences between conventional and four-dimensional computed tomography-based treatment planning and whether gating could improve dose volume parameters. Materials and methods: Ten patients with left-sided breast cancer and surgical clips at the excision site had conventional treatment planning computed tomography and four-dimensional computed tomography. Treatment plans using two tangential beams (6. MV X-rays) were optimised for target coverage and homogeneity using a field in field technique for the three-dimensional scan.