PO-0783: Design of cone-beam CT for proton therapy gantry

Brousmiche, Sébastien; Seabra, José; Labarbe, Rudi; Oliva, Matteo; Rit, Simon; Wikler, David; Lee, J.; Teo, K.; Xivry, Jonathan Orban de; Macq, Benoı̂t

doi:10.1016/s0167-8140(15)30901-4

Cited by 4 publications

(3 citation statements)

References 0 publications

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“…The gantry mounted CBCT system (Ion Beam Applications (IBA) SA, Ottignies-Louvain-la-Neuve, BE) was first used clinically at the Roberts Proton Therapy Center in September 2014 (figure 1) (Brousmiche et al 2014. This was the first IBA CBCT clinical system and was not part of the original proton room solution, but rather retrospectively fitted by updating the existing kV imaging system.…”

Section: Design Of the Gantry Mounted Cbct System For Proton Therapymentioning

confidence: 99%

A comprehensive evaluation of the accuracy of CBCT and deformable registration based dose calculation in lung proton therapy

Veiga

Janssens

Baudier

et al. 2017

Biomed. Phys. Eng. Express

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A comprehensive evaluation of the accuracy of CBCT and deformable registration based dose calculation 4 in lung proton therapy 5 The uncertainties in water equivalent thickness (WET) and accuracy of dose estimation using a virtual CT 30 (vCT), generated from deforming the planning CT (pCT) onto the daily cone-beam CT (CBCT), were 31 comprehensively evaluated in the context of lung malignancies and passive scattering proton therapy. The 32 validation methodology utilized multiple CBCT datasets to generate the vCTs of twenty lung cancer 33 patients. A correction step was applied to the vCTs to account for anatomical modifications that could not 34 be modeled by deformation alone. The CBCT datasets included a regular CBCT (rCBCT) and synthetic 35CBCTs created from the rCBCT and rescan CT (rCT), which minimized the variation in setup between the 36 vCT and the gold-standard image (i.e., rCT). The uncertainty in WET was defined as the voxelwise 37 2 difference in WET between vCT and rCT, and calculated in 3D (planning target volume, PTV) and 2D 1 (distal and proximal surfaces). The uncertainty in WET based dose warping was defined as the difference 2 between the warped dose and a forward dose recalculation on the rCT. The overall root mean square (RMS) 3 uncertainty in WET was 3.6±1.8, 2.2±1.4 and 3.3±1.8 mm for the distal surface, proximal surface and PTV, 4 respectively. For the warped dose, the RMS uncertainty of the voxelwise dose difference was 6±2% of the 5 maximum dose (%mD), using a 20% cut-off. The rCBCT resulted in higher uncertainties due to setup 6 variability with the rCT; the uncertainties reported with the two synthetic CBCTs were similar. The vCT 7 followed by a correction step was found to be an accurate alternative to rCT.

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Section: Design Of the Gantry Mounted Cbct System For Proton Therapymentioning

confidence: 99%

A comprehensive evaluation of the accuracy of CBCT and deformable registration based dose calculation in lung proton therapy

Veiga

Janssens

Baudier

et al. 2017

Biomed. Phys. Eng. Express

View full text Add to dashboard Cite

show abstract

“…Kilovoltage CBCT has been an indispensable tool (72) for lung photon therapy. For proton therapy, CBCT has been implemented by utilizing a gantry or nozzle mounted X-ray imaging system for image acquisition (73). X-ray projection images are acquired through gantry rotation in a similar way CBCT is acquired on linacs.…”

Section: Image Guidance Tools For Proton Therapy Systemsmentioning

confidence: 99%

Image guidance in proton therapy for lung cancer

Zhang

Zou

Teo

2018

Transl. Lung Cancer Res.

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Proton therapy is a promising but challenging treatment modality for the management of lung cancer. The technical challenges are due to respiratory motion, low dose tolerance of adjacent normal tissue and tissue density heterogeneity. Different imaging modalities are applied at various steps of lung proton therapy to provide information on target definition, target motion, proton range, patient setup and treatment outcome assessment. Imaging data is used to guide treatment design, treatment delivery, and treatment adaptation to ensure the treatment goal is achieved. This review article will summarize and compare various imaging techniques that can be used in every step of lung proton therapy to address these challenges.

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“…To improve patients' setup accuracy, various advanced imaging techniques, such as Cone-Beam Computed Tomography (CBCT) and surface imaging techniques, have been introduced into proton beam therapy to guide and improve the patients' setup (Brousmiche et al 2014). However, the setup uncertainties still exist even with these advanced image-guided radiotherapies (IGRT) techniques.…”

Section: Introductionmentioning

confidence: 99%

Introduce a rotational robust optimization framework for spot-scanning proton arc (SPArc) therapy

Chang¹,

Liu²,

Zhao³

et al. 2022

Phys. Med. Biol.

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Objective. Proton dosimetric uncertainties resulting from the patient’s daily setup errors in rotational directions exist even with advanced image-guided radiotherapy techniques. Thus, we developed a new rotational robust optimization SPArc algorithm (SPArcrot) to mitigate the dosimetric impact of the rotational setup error in Raystation ver. 6.02 (RaySearch Laboratory AB, Stockholm, Sweden). Approach. The initial planning CT was rotated ±5° simulating the worst-case setup error in the roll direction. The SPArcrot uses a multi-CT robust optimization framework by taking into account of such rotational setup errors. Five cases representing different disease sites were evaluated. Both SPArcoriginal and SPArcrot plans were generated using the same translational robust optimized parameters. To quantitatively investigate the mitigation effect from the rotational setup errors, all plans were recalculated using a series of pseudo-CT with rotational setup error (±1°/±2°/±3°/±5°). Dosimetric metrics such as D98% of CTV, and 3D gamma analysis were used to assess the dose distribution changes in the target and OARs. Main results. The magnitudes of dosimetric changes in the targets due to rotational setup error were significantly reduced by the SPArcrot compared to SPArc in all cases. The uncertainties of the max dose to the OARs, such as brainstem, spinal cord and esophagus were significantly reduced using SPArcrot. The uncertainties of the mean dose to the OARs such as liver and oral cavity, parotid were comparable between the two planning techniques. The gamma passing rate (3%/3mm) was significantly improved for CTV of all tumor sites through SPArcrot. Significance. Rotational setup error is one of the major issues which could lead to significant dose perturbations. SPArcrot planning approach can consider such rotational error from patient setup or gantry rotation error by effectively mitigating the dose uncertainties to the target and in the adjunct series OARs.

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PO-0783: Design of cone-beam CT for proton therapy gantry

Cited by 4 publications

References 0 publications

A comprehensive evaluation of the accuracy of CBCT and deformable registration based dose calculation in lung proton therapy

A comprehensive evaluation of the accuracy of CBCT and deformable registration based dose calculation in lung proton therapy

Image guidance in proton therapy for lung cancer

Introduce a rotational robust optimization framework for spot-scanning proton arc (SPArc) therapy

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