Evaluation of the OSC‐TV iterative reconstruction algorithm for cone‐beam optical CT

Matenine, Dmitri; Mascolo-Fortin, Julia; Goussard, Yves; Després, Philippe

doi:10.1118/1.4931604

Cited by 15 publications

(11 citation statements)

References 39 publications

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“…We can take combating strategies from three perspectives: (a) when performing scanning experiments, we should strictly follow the preparation and scanning protocol and be careful in every task, as detailed in Doran (2010); (b) in most cases, anomalies in raw data are inevitable, and we should pre-process the raw data before reconstruction, including bad pixel removal and refraction correction; (c) in reconstruction, iterative algorithms are preferred rather than commonly used filtered backprojection type algorithms (FBP for 2D geometry, and FDK for 3D cone beam geometry). Our preliminary study using the simultaneous iterative reconstruction technique (SIRT) (Yi et al 2015), revealed the potential of iterative algorithms over FBP in optical-CT noise and artefacts suppression, and following papers by other groups gave similar conclusions (Doran and Yatigammana 2012, Matenine et al 2015, Shih et al 2015.…”

Section: Introductionsupporting

confidence: 62%

Evaluation of hybrid SART + OS + TV iterative reconstruction algorithm for optical-CT gel dosimeter imaging

Wang

Xiang

et al. 2016

Phys. Med. Biol.

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Optical computed tomography (optical-CT) is a high-resolution, fast, and easily accessible readout modality for gel dosimeters. This paper evaluates a hybrid iterative image reconstruction algorithm for optical-CT gel dosimeter imaging, namely, the simultaneous algebraic reconstruction technique (SART) integrated with ordered subsets (OS) iteration and total variation (TV) minimization regularization. The mathematical theory and implementation workflow of the algorithm are detailed. Experiments on two different optical-CT scanners were performed for cross-platform validation. For algorithm evaluation, the iterative convergence is first shown, and peak-to-noise-ratio (PNR) and contrast-to-noise ratio (CNR) results are given with the cone-beam filtered backprojection (FDK) algorithm and the FDK results followed by median filtering (mFDK) as reference. The effect on spatial gradients and reconstruction artefacts is also investigated. The PNR curve illustrates that the results of SART + OS + TV finally converges to that of FDK but with less noise, which implies that the dose-OD calibration method for FDK is also applicable to the proposed algorithm. The CNR in selected regions-of-interest (ROIs) of SART + OS + TV results is almost double that of FDK and 50% higher than that of mFDK. The artefacts in SART + OS + TV results are still visible, but have been much suppressed with little spatial gradient loss. Based on the assessment, we can conclude that this hybrid SART + OS + TV algorithm outperforms both FDK and mFDK in denoising, preserving spatial dose gradients and reducing artefacts, and its effectiveness and efficiency are platform independent.

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Section: Introductionsupporting

confidence: 62%

Evaluation of hybrid SART + OS + TV iterative reconstruction algorithm for optical-CT gel dosimeter imaging

Wang

Xiang

et al. 2016

Phys. Med. Biol.

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“…Data reconstruction of the OCT slices was performed using the ordered subsets convex algorithm with regularization via total variation (OSC‐TV) 23 from the Vista 3‐D Reconstruction software (Modus Medical, London, Canada) with 0.5 mm 3 voxel size. Subsequent data analysis, including image registration between measured and planned dose maps, was done in Python (v. 3.8, Python software foundation).…”

Section: Methodsmentioning

confidence: 99%

Technical note: Temporal and thermal stability of optical response for silicone‐based 3D radiochromic dosimeters

et al. 2023

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Background: Radiochromic silicone-based dosimeters are flexible 3D dosimeters, which at appropriate concentration of leucomalachite green (LMG) and curing agent are dose-rate independent for clinical photon beams. However, their dose response is based on chemical processes that can be influenced by temporal and thermal conditions, impacting measurement stability. Purpose: The aim of this study was to investigate the temporal stability of the dose response of radiochromic dosimeters for different curing times and postirradiation storage temperatures. Methods: Six cylindrical dosimeters (5 cm diameter,5 cm length) were produced in a single batch and separated into two groups that were irradiated 72 and 118 h after production. The same photon plan, consisting of two 10 × 1.6 cm 2 opposing fields, was delivered to all dosimeters. After irradiation, the dosimeters were separated into three groups, stored at 5 • C, 15 • C, and 20 • C, and read out for five consecutive days. Results: Storage temperature influenced the measurement stability, and changes in the optical response with time differed between irradiated and nonirradiated parts of the dosimeters. The relative change between signal and background was greater than 10% for all measurements performed 24 h or more after irradiation, except for dosimeters stored at 5 • C, which changed by 2%-5% after 24 h. The dosimeter temporal stability was not influenced by curing time. Conclusions: For room temperature storage (15 • C and 20 • C), readout should take place as soon as possible after irradiation since the background color increased rapidly for both curing times (72 and 118 h), whereas the dosimeters are stored at 5 • C, readout can be performed up to 24 h after.

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“…Iterative algorithms have been studied for reconstruction in the case of incomplete projection data due to refraction . Additionally, noise reduction benefits have recently been demonstrated in phantoms and in polymer gel dosimeters . However, one of the challenges associated with iterative reconstruction algorithms is that they often contain one or more empirically determined constants that control either the weighting of correction terms made at each iteration, or the aggressiveness of the denoising performed.…”

Section: Introductionmentioning

confidence: 99%

“…Matenine et al. previously applied the algorithm to cone‐beam optical CT scanning, but used projection data obtained using the DeskCAT scanner (Modus Medical Devices, Inc., London, Canada). This is a dedicated educational system, which suffers from both stray light effects and refractive index mismatch between phantoms and surrounding media.…”

Section: Introductionmentioning

confidence: 99%

Technical Note: Evaluation of an iterative reconstruction algorithm for optical CT radiation dosimetry

2017

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Evaluation of the OSC‐TV iterative reconstruction algorithm for cone‐beam optical CT

Cited by 15 publications

References 39 publications

Evaluation of hybrid SART + OS + TV iterative reconstruction algorithm for optical-CT gel dosimeter imaging

Evaluation of hybrid SART + OS + TV iterative reconstruction algorithm for optical-CT gel dosimeter imaging

Technical note: Temporal and thermal stability of optical response for silicone‐based 3D radiochromic dosimeters

Technical Note: Evaluation of an iterative reconstruction algorithm for optical CT radiation dosimetry

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