Algorithm for Working with Metal Objects in Breast Expander in Radiotherapy

Abstract

Purpose: The article is devoted to the analysis of the developed algorithm of contouring minimizing dosimetric deviations during post-mastectomy radiation therapy of patients with breast tissue expanders with a metal port. The influence of the main errors in contouring the critical structures of the above patients on the quality of dosimetric planning is also considered. Material and methods: Mentor CPX4 tissue expander with a two component SmoothCast medical plastic shell imitating the patient's skin was scanned on three protocols using CT GE Optima 540, the resulting series of slices were contoured by different methods in the Eclipse planning systemand dosimetry evaluated by film dosimetry. Algorithm minimizing a contouring errors was developed. Results: When contouring on the basis of the developed algorithm, the deviation in dose compared with the value calculated in the planning system was 1.7 %. Contouring on the basis of the above errors gave a deviation in the dose up to 6.7 %. Conclusion: The developed delineation algorithm can be used both in departments with the presence of CT with the “extended curve” function, and in departments where this function is unavailable in CT.