The use of new delineation tool "MIRADA" at the level of regional lymph nodes, step-by-step development and first results for early-stage breast cancer patients.

Abstract

To describe the practical procedure of implementation and optimization of delineation using "Mirada" software, as well as evaluation of the automatic segmentation for the daily practice of lymph nodes (LN) and organs at risk (OARs) in early stage breast cancer patients. 40 patients' CT scans in treatment position were selected and recontoured according to the European Society of Therapeutic Radiation Oncology guidelines. The atlas of dataset was then created for automatic delineation. 30 patients with breast/chest wall and lymph nodes regions irradiated were recruited for evaluation. With the same treatment position, the CT scan images were acquired and then contoured by the MIRADA system automatically as well as by the radiation oncologist manually (as the reference). The conformity index (CI) was used to evaluate the concordance between both of them. The mean time for manual contour was 24.1 ± 5.1 and 26.4 ± 2.8 min for the LN and the OARs respectively. All the volumes of interest were contoured using the software (including corrections) in 30 min, which reduced the time of delineation of target volumes and OAR by about 40%. Of the 30 cases evaluated, the mean CI of 5 principal OARs showed ≥0.8. While the automatic contour of LN was less satisfactory with mean CI of 0.43 ± 0.1(0.23-0.52). For the breast cancer patients, the studied software permitted to save time for delineation with acceptable OAR contours. The improvement of LN regions contour is needed. More cases and further evaluation are needed for the system to realize its routine use. It's the first description and evaluation of the automatic delineation and segmentation system for the breast cancer.