Tissue Equivalence Correction in Silicon Microdosimetry for Protons Characteristic of the LEO Space Environment

Guatelli, Susanna; Reinhard, Mark I.; Mascialino, B.; Prokopovich, Dale A.; Dzurak, A. S.; Zaider, Marco; Rosenfeld, Anatoly B.

doi:10.1109/tns.2008.2006894

Cited by 27 publications

(21 citation statements)

References 22 publications

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“…However, since we are ultimately interested in quantities relevant to human tissue, we use the mean path length in tissue. The corresponding tissue‐equivalent mean path length was determined by Monte Carlo to be 17.24 μm. In the simulation, energy deposition was calculated in the silicon SV exposed to a 150 MeV proton beam radiation field along the Bragg peak.…”

Section: Methodsmentioning

confidence: 99%

Microdosimetric measurements of a clinical proton beam with micrometer‐sized solid‐state detector

et al. 2017

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Purpose: Microdosimetry is a vital tool for assessing the microscopic patterns of energy deposition by radiation, which ultimately govern biological effect. Solid-state, silicon-on-insulator microdosimeters offer an approach for making microdosimetric measurements with high spatial resolution (on the order of tens of micrometers). These high-resolution, solid-state microdosimeters may therefore play a useful role in characterizing proton radiotherapy fields, particularly for making highly resolved measurements within the Bragg peak region. In this work, we obtain microdosimetric measurements with a solid-state microdosimeter (MicroPlus probe) in a clinical, spot-scanning proton beam of small spot size. Methods: The MicroPlus probe had a 3D single sensitive volume on top of silicon oxide. The sensitive volume had an active cross-sectional area of 250 lm 9 10 lm and thickness of 10 lm. The proton facility was a synchrotron-based, spot-scanning system with small spot size (r % 2 mm). We performed measurements with the clinical beam current (%1 nA) and had no detected pulse pile-up. Measurements were made in a water-equivalent phantom in water-equivalent depth (WED) increments of 0.25 mm or 1.0 mm along pristine Bragg peaks of energies 71.3 MeV and 159.9 MeV, respectively. For each depth, we measured lineal energy distributions and then calculated the dose-weighted mean lineal energy, y D . The measurements were repeated for two field sizes: 4 9 4 cm 2 and 20 9 20 cm Conclusions: We performed microdosimetric measurements with a novel solid-state, silicon-oninsulator microdosimeter in a clinical spot-scanning proton beam of small spot size and unmodified beam current. For all of the proton field sizes and energies considered, the measurements of y D were in agreement with expected trends. Furthermore, we obtained measurements with a spatial resolution of 10 lm in the beam direction. This spatial resolution greatly exceeded that possible with a conventional gaseous tissue-equivalent proportional counter and allowed us to perform a high-resolution investigation within the Bragg peak region. The MicroPlus probe is therefore suitable for applications in proton radiotherapy.

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Section: Methodsmentioning

confidence: 99%

Microdosimetric measurements of a clinical proton beam with micrometer‐sized solid‐state detector

et al. 2017

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“…Once that information is available, one can use existing radiation transport codes to predict the detailed nature of the radiation exposure to various organs and tissues throughout the body and using the most appropriate parameterizations of biological detriment. Finally, in cases where immediate dosimetry estimates are needed, the track-by-track absorbed dose in water can also be determined by using particle-and energy-dependent conversion factors between the sensor material and water (Guatelli et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

A semiconductor radiation imaging pixel detector for space radiation dosimetry

Kroupa

Bahadori

Campbell-Ricketts

et al. 2015

Life Sciences in Space Research

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“…where the Absorbed Dose in silicon DSi is multiplied by the Tissue Equivalent factor 0.58 obtained from tissue equivalency studies for mixed fields [20,21]. Finally, the Dose Equivalent is calculated with the following formula:…”

Section: B Characterization Of the Response Of The 3d Mushroom Micromentioning

confidence: 99%

Modelling of the Silicon-On-Insulator microdosimeter response within the International Space Station for astronauts’ radiation protection

Peracchi

Vohradsky

Guatelli

et al. 2019

Radiation Measurements

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Astronauts are exposed to high-energy cosmic radiation which may have harmful health effects. At the altitude of the International Space Station (ISS), the main radiation sources are Galactic Cosmic Rays (GCRs), Solar Particle Events (SPEs) and trapped protons of the Van Allen Belts. The radiation field mainly consists of protons, helium nuclei and heavy ions with energies up to hundreds of GeV/n. A powerful approach to determine the effect of space radiation on astronauts is microdosimetry. The Centre for Medical Radiation Physics is active in the development of Silicon-On-Insulator (SOI) microdosimeters, as an alternative to Tissue Equivalent Proportional Counters (TEPCs) for radiation protection purposes. SOI microdosimeters are portable and do not require a high-voltage power supply. They consist of a matrix of silicon Sensitive Volumes (SV), which mimic the dimensions of biological cells. In this study, we investigated for the first time the response of the 3D "Mushroom" microdosimeter, a type of SOI microdosimeter in the Columbus module of the ISS. Tissue-equivalent microdosimetric spectra of GCRs, SPEs, and trapped protons were obtained to estimate the dose equivalent delivered to the astronauts. Results demonstrate a non-negligible production of secondary particles due to the propagation of space radiation through the wall of the Columbus and the microdosimeter. A number of heavy ions were detected with high lineal energies, these events pose a significant hazard in terms of radiation protection. Moreover, the dose evaluation shows a good agreement with experimental data found in the literature, confirming the suitability of our Geant4 model and the feasibility of using the SOI microdosimeter for ISS astronauts' personal dosimetry.

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Tissue Equivalence Correction in Silicon Microdosimetry for Protons Characteristic of the LEO Space Environment

Cited by 27 publications

References 22 publications

Microdosimetric measurements of a clinical proton beam with micrometer‐sized solid‐state detector

Microdosimetric measurements of a clinical proton beam with micrometer‐sized solid‐state detector

A semiconductor radiation imaging pixel detector for space radiation dosimetry

Modelling of the Silicon-On-Insulator microdosimeter response within the International Space Station for astronauts’ radiation protection

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