A reflected-scanned ultrasound system for external simultaneousthermoradiotherapy

摘要

The simultaneous delivery of hyperthermia and ionizing radiationnhas the potential to improve clinical outcome. To this purpose, anscanning ultrasound reflector-linear array system (SURLAS) with thenability both to conform power to superficial volumes and to operatenconcomitantly with medical linear accelerators is currently underndevelopment. In this purpose-specific design, the ultrasound wavesngenerated by a linear array are directed toward a scanning reflectornwhich in turn deflects the waves toward the target. In previousnexperiments, the technical feasibility of this design was demonstrated.nHere, the authors are concerned with the minimization of a key designnparameter, namely, the array element size, in order to minimize thenamount of attenuating/scattering water-equivalent medium that a photonnor a electron beam passes through before entering the target. First, thenSURLAS design is described. Second, an acoustic model to compute powerndeposition patterns is presented. This model is coupled to a bioheatntransfer model for computation of temperature fields. Third, an analysisnis performed to determine the minimum array element size for threentarget categories. Finally, acoustic fields and temperaturendistributions induced by the SURLAS for the three target categories arenpresented. The analysis and simulations show that the SURLAS has thenpotential to induce uniform temperature distributions in largensuperficial volumes with small enough elements to allow simultaneousndelivery with electron beam therapy