PO-1405: SBRT/SRS patient-specific QA using GAFchromic EBT3 e FilmQA software

Stella, Giuseppe; Cavalli, N.; Bonanno, E.; Gueli, Anna Maria; Girlando, A.; Marino, C.

doi:10.1016/s0167-8140(21)01423-7

Cited by 2 publications

(2 citation statements)

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“…A common method for performing a quantitative comparison of calculated and measured distributions is the calculation of the Gamma Index Passing Rate (GIPR), first introduced by Low et al [ 44 , 45 ]. The Gamma Index (GI) quantifies the difference between measured and calculated dose distributions on a point-by-point basis by combining two acceptability criteria: the dose difference (DD) and the distance to agreement (DTA).…”

Section: Methodsmentioning

confidence: 99%

HyperArcTM Dosimetric Validation for Multiple Targets Using Ionization Chamber and RT-100 Polymer Gel

Zirone¹,

Bonanno²,

Borzì³

et al. 2022

Gels

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Multiple brain metastases single-isocenter stereotactic radiosurgery (SRS) treatment is increasingly employed in radiotherapy department. Before its use in clinical routine, it is recommended to perform end-to-end tests. In this work, we report the results of five HyperArcTM treatment plans obtained by both ionization chamber (IC) and polymer gel. The end-to-end tests were performed using a water equivalent Mobius Verification PhantomTM (MVP) and a 3D-printed anthropomorphic head phantom PseudoPatient® (PP) (RTsafe P.C., Athens, Greece); 2D and 3D dose distributions were evaluated on the PP phantom using polymer gel (RTsafe). Gels were read by 1.5T magnetic resonance imaging (MRI). Comparison between calculated and measured distributions was performed using gamma index passing rate evaluation by different criteria (5% 2 mm, 3% 2 mm, 5% 1 mm). Mean point dose differences of 1.01% [min −0.77%–max 2.89%] and 0.23% [min 0.01%–max 2.81%] were found in MVP and PP phantoms, respectively. For each target volume, the obtained results in terms of gamma index passing rate show an agreement > 95% with 5% 2 mm and 3% 2 mm criteria for both 2D and 3D distributions. The obtained results confirmed that the use of a single isocenter for multiple lesions reduces the treatment time without compromising accuracy, even in the case of target volumes that are quite distant from the isocenter.

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Section: Methodsmentioning

confidence: 99%

HyperArcTM Dosimetric Validation for Multiple Targets Using Ionization Chamber and RT-100 Polymer Gel

Zirone¹,

Bonanno²,

Borzì³

et al. 2022

Gels

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“…Gafchromic EBT3 films (Ashland Inc., Wayne, NJ, USA), currently the most widely used radiochromic films, feature high spatial resolution, tissue equivalence characteristics, and the advantage of two-dimensional (2D) measurements [2,3]. These films are also used for quality assurance and to determine in vivo dosimetry when administering advanced radiotherapy techniques like intensity-modulated radiation therapy and volumetric-modulated arc therapy [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Determination of Absorbed Dose for Gafchromic EBT3 Film Using Texture Analysis of Scanning Electron Microscopy Images: A Feasibility Study

Park

2022

Progress in Medical Physics

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We subjected scanning electron microscopic (SEM) images of the active layer of EBT3 film to texture analysis to determine the dose-response curve.Methods: Uncoated Gafchromic EBT3 films were prepared for direct surface SEM scanning.Absorbed doses of 0-20 Gy were delivered to the film's surface using a 6 MV TrueBeam STx photon beam. The film's surface was scanned using a SEM under 100× and 3,000× magnification. Four textural features (Homogeneity, Correlation, Contrast, and Energy) were calculated based on the gray level co-occurrence matrix (GLCM) using the SEM images corresponding to each dose. We used R-square to evaluate the linear relationship between delivered doses and textural features of the film's surface.Results: Correlation resulted in higher linearity and dose-response curve sensitivity than Homogeneity, Contrast, or Energy. The R-square value was 0.964 for correlation using 3,000× magnified SEM images with 9-pixel offsets. Dose verification was used to determine the difference between the prescribed and measured doses for 0, 5, 10, 15, and 20 Gy as 0.09, 1.96, −2.29, 0.17, and 0.08 Gy, respectively.Conclusions: Texture analysis can be used to accurately convert microscopic structural changes to the EBT3 film's surface into absorbed doses. Our proposed method is feasible and may improve the accuracy of film dosimetry used to protect patients from excess radiation exposure.

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PO-1405: SBRT/SRS patient-specific QA using GAFchromic EBT3 e FilmQA software

Cited by 2 publications

References 0 publications

HyperArcTM Dosimetric Validation for Multiple Targets Using Ionization Chamber and RT-100 Polymer Gel

HyperArcTM Dosimetric Validation for Multiple Targets Using Ionization Chamber and RT-100 Polymer Gel

Determination of Absorbed Dose for Gafchromic EBT3 Film Using Texture Analysis of Scanning Electron Microscopy Images: A Feasibility Study

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