Monte Carlo simulation of mini TEPC microdosimetric spectra: Influence of low energy electrons

Rollet, S.; Colautti, P.; Großwendt, B.; Moro, Davide; Gargioni, E.; Conte, V.; DeNardo, L.

doi:10.1016/j.radmeas.2010.06.055

Cited by 27 publications

(17 citation statements)

References 11 publications

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“…It is also seen that proton lineal energy spectra are mainly distributed between 1 and 10 keV/µm, as compared to the 60 Co γ-ray spectrum between 0.1 and 1 keV/µm. [22] As proton energy decreases, a greater portion of the spectra falls in the range of lineal energy larger than 10 keV/µm.…”

Section: Resultsmentioning

confidence: 98%

“…In addition to experimental measurements, MC transport codes can be employed to determine the lineal energy spectra. Studies demonstrated that MC FLUKA code [20,21] was able to predict the spectra of proton beams [22] and heavy-ion beams. [23] In the simulations, energy losses, energy loss straggling, scattering, and nuclear interactions of all primary and secondary particles can be included.…”

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confidence: 99%

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Microdosimetric relative biological effectiveness of therapeutic proton beams

Tung

2015

Biomed J

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I n particle (proton or heavy-ion) therapy, the patient treatment planning includes assessments of radiation dose and radiation quality. Distributions of the absorbed dose and the relative biological effectiveness (RBE), a quality index, in the patient provide essential information in the treatment planning. To facilitate these assessments, the International Atomic Energy Agency and the International Commission on Radiation Units and Measurements (ICRU) have jointly recommended the reporting and recording of isoeffective doses in the treatment plan.[1] The isoeffective dose, that is, the product of absorbed dose and isoeffective weighting factor, of particle beam is defined as the equivalent dose of photon beam under the same irradiation conditions (e.g., 2 Gy per fraction, 5 daily fractions per week, etc.). The key factor determining the isoeffective weighting factor is the RBE. While absorbed dose relates to the total energy deposition in a macroscopic volume of the irradiated tissue, radiation quality regards the single-event energy deposition in a microscopic volume of the biologically sensitive target. [2] When compared to photon beams, particle beams have distinct spatial distributions on the energy depositions in both the macroscopic and microscopic volumes. [3] Such distributions are responsible for the different biological consequences in the tumor and healthy cells during radiotherapy. The macroscopic distribution, that When compared to photon beams, particle beams have distinct spatial distributions on the energy depositions in both the macroscopic and microscopic volumes. In a macroscopic volume, the absorbed dose distribution shows a rapid increase near the particle range, that is, Bragg peak, as particle penetrates deep inside the tissue. In a microscopic volume, individual particle deposits its energy along the particle track by producing localized ionizations through the formation of clusters. These highly localized clusters can induce complex types of deoxyribonucleic acid (DNA) damage which are more difficult to repair and lead to higher relative biological effectiveness (RBE) as compared to photons. To describe the biological actions, biophysical models on a microscopic level have been developed. In this review, microdosimetric approaches are discussed for the determination of RBE at different depths in a patient under particle therapy. These approaches apply the microdosimetric lineal energy spectra obtained from measurements or calculations. Methods to determine these spectra will be focused on the tissue equivalent proportional counter and the Monte Carlo program. Combining the lineal energy spectrum and the biological model, RBE can be determined. Three biological models are presented. A simplified model applies the dose-mean lineal energy and the measured RBE (linear energy transfer) data. A more detailed model makes use of the full lineal energy spectrum and the biological weighting function spectrum. A comprehensive model calculates the spectrum-averaged yields of DNA damages caused by ...

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Section: Resultsmentioning

confidence: 98%

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confidence: 99%

Microdosimetric relative biological effectiveness of therapeutic proton beams

Tung

2015

Biomed J

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“…The cylindrical mini-TEPC (De Nardo et al, 2004a) has a cylindrical SV of 0.9 mm in diameter and height and is axially defined by two Rexolite ((C 8 H 8 ) n ) insulator disks. The gas cavity is filled with TE gas and surrounded by a 0.35 mmthick A-150-cathode wall, a 0.35 mm thick Rexolite® insulator and a 0.2 mm thick aluminum sleeve for a total external diameter of 2.7 mm (Rollet et al, 2010).…”

Section: Microdosimeter Models In Topasmentioning

confidence: 99%

The microdosimetric extension in TOPAS: development and comparison with published data

et al. 2019

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Microdosimetric energy depositions have been suggested as a key variable for the modeling of the relative biological effectiveness (RBE) in proton and ion radiation therapy. However, microdosimetry has been underutilized in radiation therapy. Recent advances in detector technology allow the design of new mico-and nano-dosimeters. At the same time Monte Carlo simulations have become more widely used in radiation therapy. In order to address the growing interest in the field, a microdosimetric extension was developed in TOPAS. The extension provides users with the functionality to simulate microdosimetric spectra as well as the contribution of secondary particles to the spectra, calculate microdosimetric parameters, and determine RBE with a biological weighting function approach or with the microdosimetric kinetic model. Simulations were conducted with the extension and the results were compared with published experimental data and other simulation results for three types of microdosimeters, a spherical tissue equivalent proportional counter (TEPC), a cylindrical TEPC and a solid state microdosimeter. The corresponding microdosimetric spectra obtained with TOPAS from the plateau region to the distal tail of the Bragg curve generally show good agreement with the published data.

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“…Additionally, FLUKA's ability to simulate the response of a TEPC has been well documented. Comparisons with experimental data have been performed for TEPCs exposed to photons (Rollet et al 2004(Rollet et al , 2007(Rollet et al , 2010; neutrons (Rollet et al 2004); protons (Rollet et al 2011;Böhlen et al 2011); C ions (Böhlen et al 2011(Böhlen et al , 2012; He, N, O, Ne, and Si ions (Böhlen et al 2011); and Fe ions (Böhlen et al 2011;Northum et al 2012). Additionally, FLUKA has been used to successfully simulate the response of a TEPC to cosmic rays on board commercial aircraft (Beck et al 2005).…”

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Simulated Response of a Tissue-equivalent Proportional Counter on the Surface of Mars

et al. 2015

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Uncertainties persist regarding the assessment of the carcinogenic risk associated with galactic cosmic ray (GCR) exposure during a mission to Mars. The GCR spectrum peaks in the range of 300(-1) MeV n to 700 MeV n(-1) and is comprised of elemental ions from H to Ni. While Fe ions represent only 0.03% of the GCR spectrum in terms of particle abundance, they are responsible for nearly 30% of the dose equivalent in free space. Because of this, radiation biology studies focusing on understanding the biological effects of GCR exposure generally use Fe ions. Acting as a thin shield, the Martian atmosphere alters the GCR spectrum in a manner that significantly reduces the importance of Fe ions. Additionally, albedo particles emanating from the regolith complicate the radiation environment. The present study uses the Monte Carlo code FLUKA to simulate the response of a tissue-equivalent proportional counter on the surface of Mars to produce dosimetry quantities and microdosimetry distributions. The dose equivalent rate on the surface of Mars was found to be 0.18 Sv y(-1) with an average quality factor of 2.9 and a dose mean lineal energy of 18.4 keV μm(-1). Additionally, albedo neutrons were found to account for 25% of the dose equivalent. It is anticipated that these data will provide relevant starting points for use in future risk assessment and mission planning studies.

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Monte Carlo simulation of mini TEPC microdosimetric spectra: Influence of low energy electrons

Cited by 27 publications

References 11 publications

Microdosimetric relative biological effectiveness of therapeutic proton beams

Microdosimetric relative biological effectiveness of therapeutic proton beams

The microdosimetric extension in TOPAS: development and comparison with published data

Simulated Response of a Tissue-equivalent Proportional Counter on the Surface of Mars

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