Influence of exposure parameters and iterative reconstruction on automatic airway segmentation and analysis on MDCT—An ex vivo phantom study

Leutz-Schmidt, Patricia; Weinheimer, Oliver; Jobst, Bertram; Dinkel, Julien; Biederer, Jürgen; Kauczor, Hans‐Ulrich; Puderbach, Michael; Wielpütz, Mark O.

doi:10.1371/journal.pone.0182268

Cited by 15 publications

(21 citation statements)

References 39 publications

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“…. The simplicity of this model may be contrasted with an elaborate lung phantom involving a water‐filled casing with porcine lung, a commercial synthetic torso, or a commercial pig organ phantom . Users of cork‐based phantoms should be aware of potential discrepancies between their TPS and actual stopping powers …”

Section: Discussionmentioning

confidence: 99%

Validation of the RayStation Monte Carlo dose calculation algorithm using a realistic lung phantom

Schreuder

Bridges

Rigsby

et al. 2019

J Applied Clin Med Phys

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PurposeOur purposes are to compare the accuracy of RaySearch's analytical pencil beam (APB) and Monte Carlo (MC) algorithms for clinical proton therapy and to present clinical validation data using a novel animal tissue lung phantom.MethodsWe constructed a realistic lung phantom composed of a rack of lamb resting on a stack of rectangular natural cork slabs simulating lung tissue. The tumor was simulated using 70% lean ground lamb meat inserted in a spherical hole with diameter 40 ± 5 mm carved into the cork slabs. A single‐field plan using an anterior beam and a two‐field plan using two anterior‐oblique beams were delivered to the phantom. Ion chamber array measurements were taken medial and distal to the tumor. Measured doses were compared with calculated RayStation APB and MC calculated doses.ResultsOur lung phantom enabled measurements with the MatriXX PT at multiple depths in the phantom. Using the MC calculations, the 3%/3 mm gamma index pass rates, comparing measured with calculated doses, for the distal planes were 74.5% and 85.3% for the APB and 99.1% and 92% for the MC algorithms. The measured data revealed up to 46% and 30% underdosing within the distal regions of the target volume for the single and the two field plans when APB calculations are used. These discrepancies reduced to less than 18% and 7% respectively using the MC calculations.ConclusionsRaySearch Laboratories' Monte Carlo dose calculation algorithm is superior to the pencil‐beam algorithm for lung targets. Clinicians relying on the analytical pencil‐beam algorithm should be aware of its pitfalls for this site and verify dose prior to delivery. We conclude that the RayStation MC algorithm is reliable and more accurate than the APB algorithm for lung targets and therefore should be used to plan proton therapy for patients with lung cancer.

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Section: Discussionmentioning

confidence: 99%

Validation of the RayStation Monte Carlo dose calculation algorithm using a realistic lung phantom

Schreuder

Bridges

Rigsby

et al. 2019

J Applied Clin Med Phys

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“…For the measurement of the airway, we found that the ADMIRE level had no significant influence on the measured values, which were in accordance with Leutz-Schmidt's study. 20 Furthermore, the measurement variability of %WA and WT was acceptable in the three low/ultralow-dose settings.…”

Section: Discussionmentioning

confidence: 88%

“…25,30 Its application in thoracic imaging mainly on diagnostic confidence and detectability of pulmonary nodules, 13,14,22,28,31,32 only a few on interstitial pulmonary disease, 24 pulmonary inflammation, 14 emphysema evaluation 17 , and airway assessment. 20,33 The growing morbidity and mortality of COPD has given rise to suggestions for screening using low/ultralow-dose CT in the at-risk population for preventive treatment, 34 and to identify specific subgroups and exacerbation which may be amenable to therapy. 1 Therefore, we studied the image quality using low/ultralow-dose CT, low kV settings, and ADMIRE levels, and analyzed the impact on bronchial wall quantification.…”

Section: Discussionmentioning

confidence: 99%

“…13 For airway measurements, an ex vivo study showed that a low radiation dose (minimum of 0.25 mGy) did not influence measured airway parameters using IR. 20 An in vivo large animal study showed that ultralow-dose CT protocols had small measurement differences of % WA and WT in small airways. 33 In our study, similar to previous results, 20,33,35 %WA and WT were not significantly influenced by dose reduction, although the variability of measurements slightly increased.…”

Section: Discussionmentioning

confidence: 99%

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Feasibility of bronchial wall quantification in low‐ and ultralow‐dose third‐generation dual‐source CT: An ex vivo lung study

Zhang

Pelgrim

Yan

et al. 2020

J Applied Clin Med Phys

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Purpose To investigate image quality and bronchial wall quantification in low‐ and ultralow‐dose third‐generation dual‐source computed tomography (CT). Methods A lung specimen from a formerly healthy male was scanned using third‐generation dual‐source CT at standard‐dose (51 mAs/120 kV, CTDI vol 3.41 mGy), low‐dose (1/4th and 1/10th of standard dose), and ultralow‐dose setting (1/20th). Low kV (70, 80, 90, and Sn100 kV) scanning was applied in each low/ultralow‐dose setting, combined with adaptive mAs to keep a constant dose. Images were reconstructed at advanced modeled iterative reconstruction (ADMIRE) levels 1, 3, and 5 for each scan. Bronchial wall were semi‐automatically measured from the lobar level to subsegmental level. Spearman correlation analysis was performed between bronchial wall quantification (wall thickness and wall area percentage) and protocol settings (dose, kV, and ADMIRE). ANOVA with a post hoc pairwise test was used to compare signal‐to‐noise ratio (SNR), noise and bronchial wall quantification values among standard‐ and low/ultralow‐dose settings, and among ADMIRE levels. Results Bronchial wall quantification had no correlation with dose level, kV, or ADMIRE level (|correlation coefficients| < 0.3). SNR and noise showed no statistically significant differences at different kV in the same ADMIRE level (1, 3, or 5) and in the same dose group ( P > 0.05). Generally, there were no significant differences in bronchial wall quantification among the standard‐ and low/ultralow‐dose settings, and among different ADMIRE levels ( P > 0.05). Conclusion The combined use of low/ultralow‐dose scanning and ADMIRE does not influence bronchial wall quantification compared to standard‐dose CT. This specimen study suggests the potential that an ultralow‐dose scan can be used for bronchial wall quantification.

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“…This system uses a copolymer container constructed to simulate a chest that holds the heart and inflated lung explant of a pig by continuous evacuation of the artificial pleural space with 2-3 × 10 3 Pa (Fig 1). The shell as well as a rubber dome can be filled with pure water to simulate the attenuation of the chest wall and upper abdomen, respectively, (Artichest, PROdesign GmbH, Heiligkreuzsteinach, Germany) which has been described previously [13,[17][18][19][20][21].…”

Section: Anthropomorphic Ex Vivo Porcine Chest Phantommentioning

confidence: 99%

Influence of acquisition settings and radiation exposure on CT lung densitometry—An anthropomorphic ex vivo phantom study

et al. 2020

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Objectives To systematically evaluate the influence of acquisition settings in conjunction with raw-data based iterative image reconstruction (IR) on lung densitometry based on multi-row detector computed tomography (CT) in an anthropomorphic chest phantom. Materials and methods Ten porcine heart-lung explants were mounted in an ex vivo chest phantom shell, six with highly and four with low attenuating chest wall. CT (Somatom Definition Flash, Siemens Healthineers) was performed at 120kV p and 80kV p , each combined with current-time products of 120, 60, 30, and 12mAs, and was reconstructed with filtered back projection (FBP) and IR (Safire, Siemens Healthineers). Mean lung density (LD), air density (AD) and noise were measured by semi-automated region-of interest (ROI) analysis, with 120kV p /120 mAs serving as the standard of reference. Results Using IR, noise in lung parenchyma was reduced by~31% at high attenuating chest wall and by~22% at low attenuating chest wall compared to FBP, respectively (p<0.05). IR induced changes in the order of ±1 HU to mean absolute LD and AD compared to corresponding FBP reconstructions which were statistically significant (p<0.05). Conclusions Densitometry is influenced by acquisition parameters and reconstruction algorithms to a degree that may be clinically negligible. However, in longitudinal studies and clinical research identical protocols and potentially other measures for calibration may be required.

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Influence of exposure parameters and iterative reconstruction on automatic airway segmentation and analysis on MDCT—An ex vivo phantom study

Cited by 15 publications

References 39 publications

Validation of the RayStation Monte Carlo dose calculation algorithm using a realistic lung phantom

Validation of the RayStation Monte Carlo dose calculation algorithm using a realistic lung phantom

Feasibility of bronchial wall quantification in low‐ and ultralow‐dose third‐generation dual‐source CT: An ex vivo lung study

Influence of acquisition settings and radiation exposure on CT lung densitometry—An anthropomorphic ex vivo phantom study

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