Analysis of parameters that influence the amplitude of the ESR/alanine signal after irradiation

Dolo, Jean‐Michel; Feaugas, V.

doi:10.1016/j.apradiso.2004.08.018

Cited by 17 publications

(9 citation statements)

References 10 publications

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“…Therefore, precise EPR dosimetry protocols correct for the associated signal loss over time. Fading rates may depend on the manufacturing process (Anton 2008) as well as on the pre-and post-irradiation storage conditions (Arber andSharpe 1993, Dolo andFeaugas 2005). Hence, fading measurements need to be performed for each specific type of pellet and the applied storage conditions.…”

Section: Spectral Evaluationmentioning

confidence: 99%

A practical EPR dosimetry system for routine use in radiotherapy: uncertainty analysis of lithium formate dosimeters at the therapeutic dose level

et al. 2021

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In electron paramagnetic resonance (EPR) dosimetry, solid dosimeter materials such as alanine (AL) or, more recently, lithium formate monohydrate (LFM) are typically used. These materials offer high potential for applications in radiotherapy based on their favorable dosimetric properties. Nevertheless, EPR dosimetry is not widespread in the clinics. This work presents an uncertainty analysis of EPR dosimetry in the dose range from 1 to 70 Gy using a compact spectrometer and applying a practical procedure being suitable for routine use in radiotherapy. The performances of self-pressed LFM pellets and commercial AL pellets are compared side by side. All pellets had a diameter of 4 mm and a height of 2 mm (AL) or 4 mm (LFM). The mean pellet mass was 35.81 mg and 73.81 mg for AL and LFM, respectively. Before irradiation, the pellets were stored for at least 8 weeks at 34± 2 % relative humidity. For irradiation, the pellets were put inside an airtight capsule. In total, 25 pellets per material were examined. The pellets were irradiated at a temperature of 25 ± 2.5 (2σ) °C to doses of either 1, 5, 20, 50 or 70 Gy (five pellets per dose value and material) by a clinical 6 MV photon beam. Measurement uncertainties were obtained from five independent readouts per pellet within five weeks following irradiation using a benchtop EPR spectrometer. The measurement time of a single readout was restricted to 10 min per pellet. Dose values were derived from EPR signal amplitudes using a specifically developed spectral fitting procedure. Signal fading characteristics were analyzed and taken into account during evaluation. The relative dose uncertainties (1σ) for a single readout at doses ≥ 5 Gy are below 2.8% (AL) and 1.1% (LFM) but increase to 12.3% (AL) and 2.6% (LFM) at 1 Gy. By averaging five independent readouts, the uncertainties at 1 Gy decrease to 2.6% (AL) and 0.8% (LFM). In terms of dose uncertainty, the LFM pellets are superior to the commercial AL pellets owing to their narrower EPR spectrum and approximately doubled mass resulting in higher EPR signal intensities. In case of the LFM pellets, the EPR dosimetry system shows a high level of precision (< 3%) down to 1 Gy being preferable for applications in radiotherapy. The uncertainties can be further decreased by averaging multiple dose values from independent readouts.

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Section: Spectral Evaluationmentioning

confidence: 99%

A practical EPR dosimetry system for routine use in radiotherapy: uncertainty analysis of lithium formate dosimeters at the therapeutic dose level

et al. 2021

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“…However, relative humidity (RH) must be controlled during measurements and storage to maintain it as constant as possible (Arber and Sharpe, 1993;Dolo and Feaugas, 2005). Indeed, pellets take up or release water correspondingly to ambient RH, which has an effect on the measurements namely the ESR intensity and the mass of pellets.…”

Section: Introductionmentioning

confidence: 99%

A methodology for choosing parameters for ESR readout of alanine dosimeters for radiotherapy

Garcia

Lin

Pasquié

et al. 2009

Radiation Physics and Chemistry

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“…Factor (1) refers to the spectrometer sensitivity, storage and measurements conditions of DLalanine dosimeters. According to previous reports (Dolo and Feaugas, 2005;Ciesielski et al, 2003;Nagy, 2000;Alexandre et al, 1992), the procedure used in storage and the dosimeter reading error adds uncertainties less than 3%, as shown in Table 1. Therefore, larger differences between planned and measured doses cannot be attributed to ESR measurements.…”

Section: In Vivo Assessmentmentioning

confidence: 94%

Measurement of rectum dose by in vivo alanine/ESR dosimetry in gynecological 192Ir HDR brachytherapy

Bravo-Miranda

Rech

Oliveira

et al. 2015

Radiation Measurements

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Analysis of parameters that influence the amplitude of the ESR/alanine signal after irradiation

Cited by 17 publications

References 10 publications

A practical EPR dosimetry system for routine use in radiotherapy: uncertainty analysis of lithium formate dosimeters at the therapeutic dose level

A practical EPR dosimetry system for routine use in radiotherapy: uncertainty analysis of lithium formate dosimeters at the therapeutic dose level

A methodology for choosing parameters for ESR readout of alanine dosimeters for radiotherapy

Measurement of rectum dose by in vivo alanine/ESR dosimetry in gynecological 192Ir HDR brachytherapy

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