Radiation oncology
Microbeam radiotherapy - clinical and dosimetric investigation of a first clinical application
By Kraus KM, Day LR, Wilkens JJ and 2 others.
Abstract
Background
Microbeam Radiotherapy (MRT) is an emerging radiotherapy technique which delivers spatially fractionated beams on a micrometre scale. In preclinical studies MRT has demonstrated superior normal tissue sparing compared to conventional radiotherapy while maintaining tumour control. However, MRT has traditionally been achievable only at large synchrotron facilities which has impeded clinical translation. The development of a compact line-focus X-ray tube (LFXT) provides a pathway for clinical MRT, but identification of clinically and dosimetrically suitable patient scenarios is required for first-in-human trials.
Materials and methods
Potentially eligible patients were selected from our patient cohort based on clinical criteria including palliative treatment indication, superficial tumour location, reproducible and safe positioning, minimal interference from other therapies, and expected benefit from MRT. Three-dimensional forward treatment planning was performed in Eclipse using gantry rotations, collimator positioning, and conformal masks to treat the clinical target volume (CTV). Dose was calculated in Eclipse using a custom Monte Carlo-based hybrid algorithm adapted for the compact LFXT system with a 300 kVp beam and an eccentric focal spot. A single-fraction equivalent uniform doses (EUD) of 3 Gy was prescribed to the target volume. Dose distributions were analysed using dose-volume histograms (DVHs), peak and valley depth dose profiles, and peak-to-valley dose ratios (PVDRs).