New 3D Silicon detectors for dosimetry in Microbeam Radiation Therapy

Micro-Mini & Nano-Dosimetry & Innovative Technologies in Radiation Therapy

Lerch, M.L.F.^1 ; Dipuglia, A.^1 ; Cameron, M.^1 ; Fournier, P.^1 ; Davis, J.^1 ; Petasecca, M.^1 ; Cornelius, I.^1 ; Perevertaylo, V.^2 ; Rosenfeld, A.B.^1

Centre for Medical Radiation Physics, University of Wollongong, NSW

2522, Australia^1

SPA-BIT, Kiev, Ukraine^2

关键词: 3D silicon detectors;    High spatial resolution;    Microbeam Radiation Therapy;    Peak-to-valley dose ratios;    Radiation hard detectors;    Silicon strip detector;    Stringent requirement;    Synchrotron imaging;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/777/1/012009/pdf
DOI  :  10.1088/1742-6596/777/1/012009

来源: IOP

【 摘 要 】

Microbeam Radiation Therapy (MRT) involves the use of a spatially fractionated beam of synchrotron generated X-rays to treat tumours. MRT treatment is delivered via an array of high dose 'peaks' separated by low dose 'valleys'. A good Peak to Valley Dose Ratio (PVDR) is an important indicator of successful treatment outcomes. MRT dosimetry requires a radiation hard detector with high spatial resolution, large dynamic range, which is ideally real-time and tissue equivalent. We have developed a Silicon Strip Detector (SSD) and very recently, a new 3D MESA SSD to meet the very stringent requirements of MRT dosimetry. We have compared these detectors through the characterisation of the MRT radiation field at the Australian Synchrotron Imaging and Medical Beamline. The EPI SSD was able to measure the microbeam profiles and PVDRs, however the effective spatial resolution was limited by the detector alignment options available at the time. The geometry of the new 3D MESA SSD is less sensitive to this alignment restriction was able to measure the microbeam profiles within 2 μm of that expected. The 3D MESA SSD measured PVDRs were possibly affected by undesired and slow charge collection outside the sensitive volume and additional scattering from the device substrate.