Examination of THPC as an oxygen scavenger impacting VIC dosimeter thermal stability and comparison of NVP-containing polymer gel dosimeters

Jaszczak, Malwina; Kolesińska, Beata; Wach, Radosław A.; Maras, Piotr; Dudek, Mariusz; Kozicki, Marek

doi:10.1088/1361-6560/aafa86

Cited by 20 publications

(41 citation statements)

References 49 publications

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“…The dose response of VIC-T was independent of the radiation dose rate, type and energy of radiation for 6 and 15 MV photons and 12 MeV electrons; this is an improvement with respect to VIC. Spatial stability of VIC-T was recorded for well over 4 months after irradiation [25]. In summary, the results for VIC-T obtained for 0.47 T NMR and 3 T MRI (also different pulse sequences) lead to similar results to each other with respect to dose sensitivity and linear dose response.…”

Section: Calibration Of Vic and Vic-tsupporting

confidence: 58%

“…There were two polymer gel dosimeters used in this study: VIPAR CT (VIC) [21] and VIC-T [25]. 4 •5H 2 O and 0.02% hydroquinone.…”

Section: Preparation Of Polymer Gel Dosimetersmentioning

confidence: 99%

“…VIC-T polymer gel dosimeter contained 14 mM tetrakis(hydroxymethyl)phosphonium chloride (THPC) as oxygen scavenger instead of L-ascorbic acid and CuSO 4 •5H 2 O used in VIC, and a reduced gelatine concentration (5%) with respect to that in VIC. The preparation procedure, dose-response characteristics, and water equivalence of VIC-T are described in detail elsewhere [25].…”

Section: Preparation Of Polymer Gel Dosimetersmentioning

confidence: 99%

“…Two recently elaborated 3D polymer gel dosimeters have been used in this work: VIC [21] and VIC-T [25]. These newly developed polymer gel dosimeters have never been used in radiotherapy application studies with MRI readout.…”

Section: Introductionmentioning

confidence: 99%

“…These newly developed polymer gel dosimeters have never been used in radiotherapy application studies with MRI readout. However, the principle function of VIC and VIC-T polymer gel dosimeters and polyGevero® software has been lately demonstrated [20][21]25]. The polyGeVero® software package has also been recently applied by other groups in radiotherapy dosimetry studies, however, in combination with the radiochromic PRESAGE® [52] or lung-mimicking 3D dosimeters [53].…”

Section: Introductionmentioning

confidence: 99%

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Clinical radiotherapy application of N-vinylpyrrolidone-containing 3D polymer gel dosimeters with remote external MR-reading

et al. 2020

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Section: Calibration Of Vic and Vic-tsupporting

confidence: 58%

“…There were two polymer gel dosimeters used in this study: VIPAR CT (VIC) [21] and VIC-T [25]. 4 •5H 2 O and 0.02% hydroquinone.…”

Section: Preparation Of Polymer Gel Dosimetersmentioning

confidence: 99%

Section: Preparation Of Polymer Gel Dosimetersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Clinical radiotherapy application of N-vinylpyrrolidone-containing 3D polymer gel dosimeters with remote external MR-reading

et al. 2020

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Application of high field magnetic resonance microimaging in polymer gel dosimetry

et al. 2020

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The purpose of this work was to examine the suitability of VIPAR nd polymer gel-9.4 T magnetic resonance microimaging system for high spatial resolution dose distribution measurements. Methods: The VIPAR nd samples (3 cm in outside diameter and 12 cm in height) were exposed to ionizing radiation by using a linear accelerator (Varian TrueBeam, USA; 6 MV x-ray beam). In the calibration stage, nine gel dosimeter vials were irradiated in a water phantom homogenously to the doses from 1.5 to 30 Gy in order to obtain R2-dose relation. In the verification stage, two gel dosimeter vials were irradiated in the half beam penumbra area of 10 9 10 cm radiation field using the amount of monitor units appropriate to deliver 20 Gy at the field center. The gels were imaged on a vertical 9.4 T magnetic resonance (MR) microimaging scanner using single slice and multislice (9 slices) multiecho (90 9 7 ms) sequences at the spatial resolutions of 0.2-0.4 9 0.2-0.4 9 3 mm 3 and 0.2-0.4 9 0.2-0.4 9 1 mm 3 respectively. The gels were subjected to microimaging during the period of two weeks after irradiation. The reference data consisted of the dose profiles measured using the diode dosimetry, radiochromic film, ionization chamber, and the water phantom system. Results: The VIPAR nd-9.4 T MR microimaging system was characterized by the dose sensitivity of 0.067 AE 0.002 Gy À1 s À1 at day 3 after irradiation. The dose resolution at 10 Gy (at P = 95%) was equal to 0.42 Gy at day 3 after irradiation using a single slice sequence (0.2 9 0.2 9 3 mm 3) and 2.0 Gy at day 4 after irradiation using a multislice sequence (0.2 9 0.2 9 1 mm 3) for one signal acquisition (measurement time: 15 min). These values were improved by~1.4-fold when using four signal acquisitions in the single slice sequence, and by~2.78-fold for 12 signal acquisitions in the multislice sequence. Furthermore, decreasing the in-plane resolution from 0.2 9 0.2 mm 2 to 0.4 9 0.4 mm 2 resulted in a dose resolution of 0.3 Gy and 1 Gy at 10 Gy (at P = 95%) for one signal acquisition in the single slice and multislice sequences respectively (measurement time: 7.5 min). As reveals from the gamma index analysis the dose distributions measured at days 3-4 postirradiation using both VIPAR nd verification phantoms agree with the data obtained using a silicon diode, assuming 1 mm/5% criterion. A good interphantom reproducibility of the polymer gel dosimetry was proved by monitoring of two phantoms up to 10 days after irradiation. However, the agreement between the dose distributions measured using the diode and polymer gel started to get worse from day 5 after irradiation. Conclusion: The VIPAR nd-9.4T MR microimaging system allows to obtain dose resolution of 0.42 Gy at 10 Gy (at P = 95%) for a spatial resolution of 0.2 9 0.2 9 3 mm 3 (acquisition time:

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Radio‐fluorogenic nanoclay gel dosimeters with reduced linear energy transfer dependence for carbon‐ion beam radiotherapy

et al. 2022

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Purpose The precise assessment of the dose distribution of high linear energy transfer (LET) radiation remains a challenge, because the signal of most dosimeters will be saturated due to the high ionization density. Such measurements are particularly important for heavy‐ion beam cancer therapy. On this basis, the present work examined the high LET effect associated with three‐dimensional gel dosimetry based on radiation‐induced chemical reactions. The purpose of this study was to create an ion beam radio‐fluorogenic gel dosimeter with a reduced effect of LET. Methods Nanoclay radio‐fluorogenic gel (NC‐RFG) dosimeters were prepared, typically containing 100 μM dihydrorhodamine 123 (DHR123) and 2.0 wt% nanoclay together with catalytic additives promoting Fenton or Fenton‐like reactions. The radiological properties of NC‐RFG dosimeters having different compositions in response to a carbon‐ion beam were investigated using a fluorescence gel scanner. Results An NC‐RFG dosimeter capable of generating a fluorescence intensity distribution reflecting the carbon‐ion beam dose profile was obtained. It was clarified that the reduction of the unfavorable LET dependence results from an acceleration of the reactions between DHR123 and H2O2, which is a molecular radiolysis product. The effects of varying the preparation conditions on the radiological properties of these gels were also examined. The optimum H2O2 catalyst was determined to include 1 mM Fe3+ ions, and the addition of 100 mM pyridine was also found to increase the sensitivity. Conclusions This technique allows the first‐ever evaluation of the depth–dose profile of a carbon‐ion beam at typical therapeutic levels of several Gy without LET effect.

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Examination of THPC as an oxygen scavenger impacting VIC dosimeter thermal stability and comparison of NVP-containing polymer gel dosimeters

Cited by 20 publications

References 49 publications

Clinical radiotherapy application of N-vinylpyrrolidone-containing 3D polymer gel dosimeters with remote external MR-reading

Clinical radiotherapy application of N-vinylpyrrolidone-containing 3D polymer gel dosimeters with remote external MR-reading

Application of high field magnetic resonance microimaging in polymer gel dosimetry

Radio‐fluorogenic nanoclay gel dosimeters with reduced linear energy transfer dependence for carbon‐ion beam radiotherapy

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