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Evaluation of two synchronized external surrogates for 4D CT sorting

The purpose of this study was to quantify the performance and agreement between two different external surrogate acquisition systems: Varian's Real‐Time Position Management (RPM) and Philips Medical Systems' pneumatic bellows, in the context of waveform and 4D CT image analysis. Eight pati...

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Autores principales: Glide‐Hurst, Carri K., Smith, Megan Schwenker, Ajlouni, Munther, Chetty, Indrin J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5714627/
https://www.ncbi.nlm.nih.gov/pubmed/24257273
http://dx.doi.org/10.1120/jacmp.v14i6.4301
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author Glide‐Hurst, Carri K.
Smith, Megan Schwenker
Ajlouni, Munther
Chetty, Indrin J.
author_facet Glide‐Hurst, Carri K.
Smith, Megan Schwenker
Ajlouni, Munther
Chetty, Indrin J.
author_sort Glide‐Hurst, Carri K.
collection PubMed
description The purpose of this study was to quantify the performance and agreement between two different external surrogate acquisition systems: Varian's Real‐Time Position Management (RPM) and Philips Medical Systems' pneumatic bellows, in the context of waveform and 4D CT image analysis. Eight patient displacement curves derived from RPM data were inputted into a motion platform with varying amplitudes (0.5 to 3 cm) and patterns. Simultaneous 4D CT acquisition, with synchronized X‐ray on detection, was performed with the bellows and RPM block placed on the platform. Bellows data were used for online retrospective phase‐based sorting, while RPM data were used for off‐line reconstruction of raw 4D CT data. RPM and bellows breathing curves were resampled, normalized, and analyzed to determine associations between different external surrogates, relative amplitude differences, and system latency. Maximum intensity projection (MIP) images were generated, phantom targets were delineated, and volume differences, overlap index, and Dice similarity coefficient differences were evaluated. A prospective patient study of ten patients was performed and waveforms were evaluated for latency (i.e., absolute time differences) and overall agreement. 4D CT sorting quality and subtraction images were assessed. Near perfect associations between the RPM and bellows‐acquired breathing traces were found [Formula: see text]. Target volumes were [Formula: see text] for RPM and bellows targets, respectively, which was not significantly different [Formula: see text]. Negligible centroid variations were observed between bellows and RPM‐contoured MIP targets ([Formula: see text] in superior‐inferior direction). The maximum volume difference was observed for an RPM target 2.5 cc (1%) less than bellows, yielding the largest difference in centroid displacement (0.9 mm). Strong correlations in bellows and RPM waveforms were observed for all patients [Formula: see text]. Latency between external surrogates was [Formula: see text] for phantom and patient data. Negligible differences were observed between MIP, end‐exhale, and end‐inhale phase images for all cases, with delineated RPM and bellows lung volumes demonstrating a mean difference of [Formula: see text]. Dice similarity coefficients and overlap indices were near unity for phantom target volumes and patient lung volumes. Slight differences were observed in waveform and latency analysis between Philips bellows and Varian's RPM, although these did not translate to differences in image quality or impact delineations. Therefore, the two systems were found to be equivalent external surrogates in the context of 4D CT for treatment planning purposes. PACS numbers: 87.57.Q‐, 07.07.Df
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spelling pubmed-57146272018-04-02 Evaluation of two synchronized external surrogates for 4D CT sorting Glide‐Hurst, Carri K. Smith, Megan Schwenker Ajlouni, Munther Chetty, Indrin J. J Appl Clin Med Phys Radiation Oncology Physics The purpose of this study was to quantify the performance and agreement between two different external surrogate acquisition systems: Varian's Real‐Time Position Management (RPM) and Philips Medical Systems' pneumatic bellows, in the context of waveform and 4D CT image analysis. Eight patient displacement curves derived from RPM data were inputted into a motion platform with varying amplitudes (0.5 to 3 cm) and patterns. Simultaneous 4D CT acquisition, with synchronized X‐ray on detection, was performed with the bellows and RPM block placed on the platform. Bellows data were used for online retrospective phase‐based sorting, while RPM data were used for off‐line reconstruction of raw 4D CT data. RPM and bellows breathing curves were resampled, normalized, and analyzed to determine associations between different external surrogates, relative amplitude differences, and system latency. Maximum intensity projection (MIP) images were generated, phantom targets were delineated, and volume differences, overlap index, and Dice similarity coefficient differences were evaluated. A prospective patient study of ten patients was performed and waveforms were evaluated for latency (i.e., absolute time differences) and overall agreement. 4D CT sorting quality and subtraction images were assessed. Near perfect associations between the RPM and bellows‐acquired breathing traces were found [Formula: see text]. Target volumes were [Formula: see text] for RPM and bellows targets, respectively, which was not significantly different [Formula: see text]. Negligible centroid variations were observed between bellows and RPM‐contoured MIP targets ([Formula: see text] in superior‐inferior direction). The maximum volume difference was observed for an RPM target 2.5 cc (1%) less than bellows, yielding the largest difference in centroid displacement (0.9 mm). Strong correlations in bellows and RPM waveforms were observed for all patients [Formula: see text]. Latency between external surrogates was [Formula: see text] for phantom and patient data. Negligible differences were observed between MIP, end‐exhale, and end‐inhale phase images for all cases, with delineated RPM and bellows lung volumes demonstrating a mean difference of [Formula: see text]. Dice similarity coefficients and overlap indices were near unity for phantom target volumes and patient lung volumes. Slight differences were observed in waveform and latency analysis between Philips bellows and Varian's RPM, although these did not translate to differences in image quality or impact delineations. Therefore, the two systems were found to be equivalent external surrogates in the context of 4D CT for treatment planning purposes. PACS numbers: 87.57.Q‐, 07.07.Df John Wiley and Sons Inc. 2013-11-04 /pmc/articles/PMC5714627/ /pubmed/24257273 http://dx.doi.org/10.1120/jacmp.v14i6.4301 Text en © 2013 The Authors. This is an open access article under the terms of the Creative Commons Attribution (http://creativecommons.org/licenses/by/3.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Radiation Oncology Physics
Glide‐Hurst, Carri K.
Smith, Megan Schwenker
Ajlouni, Munther
Chetty, Indrin J.
Evaluation of two synchronized external surrogates for 4D CT sorting
title Evaluation of two synchronized external surrogates for 4D CT sorting
title_full Evaluation of two synchronized external surrogates for 4D CT sorting
title_fullStr Evaluation of two synchronized external surrogates for 4D CT sorting
title_full_unstemmed Evaluation of two synchronized external surrogates for 4D CT sorting
title_short Evaluation of two synchronized external surrogates for 4D CT sorting
title_sort evaluation of two synchronized external surrogates for 4d ct sorting
topic Radiation Oncology Physics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5714627/
https://www.ncbi.nlm.nih.gov/pubmed/24257273
http://dx.doi.org/10.1120/jacmp.v14i6.4301
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