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Silicon 3D Microdosimeters for Advanced Quality Assurance in Particle Therapy

Abstract

The Centre for Medical Radiation Physics introduced the concept of Silicon On Insulator (SOI) microdosimeters with 3-Dimensional (3D) cylindrical sensitive volumes (SVs) mimicking the dimensions of cells in an array. Several designs of high-definition 3D SVs fabricated using 3D MEMS technology were implemented. 3D SVs were fabricated in different sizes and configurations with diameters between 18 and 30 µm, thicknesses of 2–50 µm and at a pitch of 50 µm in matrices with volumes of 20 × 20 and 50 × 50. SVs were segmented into sub-arrays to reduce capacitance and avoid pile up in high-dose rate pencil beam scanning applications. Detailed TCAD simulations and charge collection studies in individual SVs have been performed. The microdosimetry probe (MicroPlus) is composed of the silicon microdosimeter and low-noise front–end readout electronics housed in a PMMA waterproof sheath that allows measurements of lineal energies as low as 0.4 keV/µm in water or PMMA. Microdosimetric quantities measured with SOI microdosimeters and the MicroPlus probe were used to evaluate the relative biological effectiveness (RBE) of heavy ions and protons delivered by pencil-beam scanning and passive scattering systems in different particle therapy centres. The 3D detectors and MicroPlus probe developed for microdosimetry have the potential to provide confidence in the delivery of RBE optimized particle therapy when introduced into routine clinical practice.

Category

Academic article

Language

English

Author(s)

  • Linh T. Tran
  • Bolst David
  • Benjamin James
  • Vladimir M. Pan
  • James Vohradsky
  • Stefania Peracchi
  • Lachlan Chartier
  • Emily Debrot
  • Susanna Gautelli
  • Marco Petasecca
  • Michael L.F. Lerch
  • Dale A. Prokopovich
  • Zeljko Pastuovic
  • Marco Povoli
  • Angela Kok
  • Taku Inaniwa
  • Sung Hyun Lee
  • Naruhiro Matsufuji
  • Anatoly B. Rosenfeld

Affiliation

  • University of Wollongong
  • Australian Nuclear Science and Technology Organisation
  • SINTEF Digital / Microsystems and Nanotechnology
  • Japan

Date

30.12.2021

Year

2021

Published in

Applied Sciences

ISSN

2076-3417

Publisher

MDPI

Volume

12

Issue

1

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