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Comprehensive evaluation of the high‐resolution diode array for SRS dosimetry

A high‐resolution diode array has been comprehensively evaluated. It consists of 1013 point diode detectors arranged on the two 7.7 × 7.7 cm(2) printed circuit boards (PCBs). The PCBs are aligned face to face in such a way that the active volumes of all diodes are in the same plane. All individual c...

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Autores principales: Ahmed, Saeed, Zhang, Geoffrey, Moros, Eduardo G., Feygelman, Vladimir
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6806480/
https://www.ncbi.nlm.nih.gov/pubmed/31478343
http://dx.doi.org/10.1002/acm2.12696
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author Ahmed, Saeed
Zhang, Geoffrey
Moros, Eduardo G.
Feygelman, Vladimir
author_facet Ahmed, Saeed
Zhang, Geoffrey
Moros, Eduardo G.
Feygelman, Vladimir
author_sort Ahmed, Saeed
collection PubMed
description A high‐resolution diode array has been comprehensively evaluated. It consists of 1013 point diode detectors arranged on the two 7.7 × 7.7 cm(2) printed circuit boards (PCBs). The PCBs are aligned face to face in such a way that the active volumes of all diodes are in the same plane. All individual correction factors required for accurate dosimetry have been validated for conventional and flattening filter free (FFF) 6MV beams. That included diode response equalization, linearity, repetition rate dependence, field size dependence, angular dependence at the central axis and off‐axis in the transverse, sagittal, and multiple arbitrary planes. In the end‐to‐end tests the array and radiochromic film dose distributions for SRS‐type multiple‐target plans were compared. In the equalization test (180° rotation), the average percent dose error between the normal and rotated positions for all diodes was 0.01% ± 0.1% (range −0.3 to 0.4%) and −0.01% ± 0.2% (range −0.9 to 0.9%) for 6 MV and 6MV FFF beams, respectively. For the axial angular response, corrected dose stayed within 2% from the ion chamber for all gantry angles, until the beam direction approached the detector plane. In azimuthal direction, the device agreed with the scintillator within 1% for both energies. For multiple combinations of couch and gantry angles, the average percent errors were −0.00% ± 0.6% (range: −2.1% to 1.6%) and −0.1% ± 0.5% (range −1.6% to 2.1%) for the 6MV and 6MV FFF beams, respectively. The measured output factors were largely within 2% of the scintillator, except for the 5 mm 6MV beam showing a 3.2% deviation. The 2%/1 mm gamma analysis of composite SRS measurements produced the 97.2 ± 1.3% (range 95.8‐98.5%) average passing rate against film. Submillimeter (≤0.5 mm) dose profile alignment with film was demonstrated in all cases.
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spelling pubmed-68064802019-10-28 Comprehensive evaluation of the high‐resolution diode array for SRS dosimetry Ahmed, Saeed Zhang, Geoffrey Moros, Eduardo G. Feygelman, Vladimir J Appl Clin Med Phys Radiation Oncology Physics A high‐resolution diode array has been comprehensively evaluated. It consists of 1013 point diode detectors arranged on the two 7.7 × 7.7 cm(2) printed circuit boards (PCBs). The PCBs are aligned face to face in such a way that the active volumes of all diodes are in the same plane. All individual correction factors required for accurate dosimetry have been validated for conventional and flattening filter free (FFF) 6MV beams. That included diode response equalization, linearity, repetition rate dependence, field size dependence, angular dependence at the central axis and off‐axis in the transverse, sagittal, and multiple arbitrary planes. In the end‐to‐end tests the array and radiochromic film dose distributions for SRS‐type multiple‐target plans were compared. In the equalization test (180° rotation), the average percent dose error between the normal and rotated positions for all diodes was 0.01% ± 0.1% (range −0.3 to 0.4%) and −0.01% ± 0.2% (range −0.9 to 0.9%) for 6 MV and 6MV FFF beams, respectively. For the axial angular response, corrected dose stayed within 2% from the ion chamber for all gantry angles, until the beam direction approached the detector plane. In azimuthal direction, the device agreed with the scintillator within 1% for both energies. For multiple combinations of couch and gantry angles, the average percent errors were −0.00% ± 0.6% (range: −2.1% to 1.6%) and −0.1% ± 0.5% (range −1.6% to 2.1%) for the 6MV and 6MV FFF beams, respectively. The measured output factors were largely within 2% of the scintillator, except for the 5 mm 6MV beam showing a 3.2% deviation. The 2%/1 mm gamma analysis of composite SRS measurements produced the 97.2 ± 1.3% (range 95.8‐98.5%) average passing rate against film. Submillimeter (≤0.5 mm) dose profile alignment with film was demonstrated in all cases. John Wiley and Sons Inc. 2019-09-03 /pmc/articles/PMC6806480/ /pubmed/31478343 http://dx.doi.org/10.1002/acm2.12696 Text en © 2019 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine. This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Radiation Oncology Physics
Ahmed, Saeed
Zhang, Geoffrey
Moros, Eduardo G.
Feygelman, Vladimir
Comprehensive evaluation of the high‐resolution diode array for SRS dosimetry
title Comprehensive evaluation of the high‐resolution diode array for SRS dosimetry
title_full Comprehensive evaluation of the high‐resolution diode array for SRS dosimetry
title_fullStr Comprehensive evaluation of the high‐resolution diode array for SRS dosimetry
title_full_unstemmed Comprehensive evaluation of the high‐resolution diode array for SRS dosimetry
title_short Comprehensive evaluation of the high‐resolution diode array for SRS dosimetry
title_sort comprehensive evaluation of the high‐resolution diode array for srs dosimetry
topic Radiation Oncology Physics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6806480/
https://www.ncbi.nlm.nih.gov/pubmed/31478343
http://dx.doi.org/10.1002/acm2.12696
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