Over the past 25 years, the Centre for Medical Radiation Physics at the University of Wollongong has developed the MicroPlus™ microdosimetric probe, based on a silicon on insulator (SOI) microdosimeter incoorporating 3D micron sized sensitive volumes (SVs) arrays that mimic cell nucleus dimensions. These devices, known as the “Bridge” and “Mushroom” microdosimeters (Figure 1A), were designed for relative biological effectiveness (RBE) prediction in particle therapy, boron neutron capture therapy and fast neutron therapy. 1, 2 Multiple 3D SVs designs have been realised using advanced MEMS fabrication technology, with each new generation providing significant improvements in SV definition and performance. The MicroPlus™ probe has been successfully employed to verify proton dose averaged LET (LETd) -optimised treatment plans for brain tumors. 3 It has also been used to evaluate the RBE of various ions species4 and to validate treatment planning systems for multi-ion therapy combining He, C, O and Ne ion beams. 5 Excellent agreement has been demonstrated between predicted biological effectiveness, based on measured dose mean lineal energy (y D ¯ {{yD}}), and experimentally measured cell surviving fraction in both proton and ion therapeutic beams. This presentation provides an overview of MicroPlus™ application across a range of clinical scenarios and introduces a new compact version, MicroPlus™2 (Figure 1B), developed for routine LETd and RBE-weighted dose QA in a clinical practice.
Tran et al. (Thu,) studied this question.