Physical aspects of a spatially fractionated radiotherapy technique for large soft tissue sarcomas

This work demonstrates the safety and feasibility of Lattice Radiotherapy (LRT) for large soft tissue sarcoma in neoadjuvant radiotherapy. The treatment consisted of two courses: the LRT course with a single fraction of 20 Gy delivered to high dose nuclei (HDN) regions and the conventional course with 25 fractions of 2 Gy delivered to the planning target volume. HDN shaped as cylinders with a 1 cm diameter and 1 cm height were placed within the gross tumour volume. The number of HDNs and their position were determined based on tumor size and proximity to organs at risk. Three patients were irradiated using the LRT technique.