Correction of patient positioning errors based on in-line cone beam CTs: clinical implementation and first experiences

Thilmann, Christoph; Nill, Simeon; Tücking, Thomas; Höss, Angelika; Hesse, Bernd; Dietrich, Lars E. P.; Bendl, Rolf; Rhein, B.; Häring, Peter; Thieke, Christian; Oelfke, Uwe; Debus, Jürgen; Huber, Peter E.

doi:10.1186/1748-717x-1-16

Cited by 88 publications

(27 citation statements)

References 21 publications

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“…Accordingly, the inhibition of PDGF signalling is being investigated as anticancer drugs alone and in combination with chemotherapy and radiotherapy [36-40]. Therefore, a two-fold rationale for the use of PDGF RTKI in radiation oncology might unfold: first, employing the anticancer effects of PDGF inhibition while second, simultaneously decreasing fibrosis as a common adverse side effect in radiotherapy [41,42]. However, again, it is unlikely that single pathway inhibition can completely prevent lung fibrosis, considering the intricate genetic networking associated with this complex process.…”

Section: Discussionmentioning

confidence: 99%

Late treatment with imatinib mesylate ameliorates radiation-induced lung fibrosis in a mouse model

Abdollahi

Gröne

et al. 2009

Radiat Oncol

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BackgroundWe have previously shown that small molecule PDGF receptor tyrosine kinase inhibitors (RTKI) can drastically attenuate radiation-induced pulmonary fibrosis if the drug administration starts at the time of radiation during acute inflammation with present but limited effects against acute inflammation. To rule out interactions of the drug with acute inflammation, we investigated here in an interventive trial if a later drug administration start at a time when the acute inflammation has subsided - has also beneficial antifibrotic effects.MethodsWhole thoraces of C57BL/6 mice were irradiated with 20 Gy and treated with the RTKI imatinib starting either 3 days after radiation (during acute inflammation) or two weeks after radiation (after the acute inflammation has subsided as demonstrated by leucocyte count). Lungs were monitored and analyzed by clinical, histological and in vivo non-invasive computed tomography as a quantitative measure for lung density and lung fibrosis.ResultsIrradiation induced severe lung fibrosis resulting in markedly reduced mouse survival vs. non-irradiated controls. Both early start of imatinib treatment during inflammation and late imatinib start markedly attenuated the development of pulmonary fibrosis as demonstrated by clinical, histological and qualitative and quantitative computed tomography results such as reduced lung density. Both administration schedules resulted in prolonged lifespans. The earlier drug treatment start resulted in slightly stronger beneficial antifibrotic effects along all measured endpoints than the later start.ConclusionsOur findings show that imatinib, even when administered after the acute inflammation has subsided, attenuates radiation-induced lung fibrosis in mice. Our data also indicate that the fibrotic fate is not only determined by the early inflammatory events but rather a complex process in which secondary events at later time points are important. Because of the clinical availability of imatinib or similar compounds, a meaningful attenuation of radiation-induced lung fibrosis in patients seems possible.

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Section: Discussionmentioning

confidence: 99%

Late treatment with imatinib mesylate ameliorates radiation-induced lung fibrosis in a mouse model

Abdollahi

Gröne

et al. 2009

Radiat Oncol

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“…In the past several years, kV-CBCT has become an important tool for localization and patient monitoring in traditionally fractionated and hypofractionated RT. [29][30][31][32][33][34][35][36][37][38][39] Traditional CT uses a fan shaped x-ray beam to acquire one or more thin slices (0.06-2.4 cm in length) per tube=detector rotation. In contrast, kV-CBCT uses a cone-shaped x-ray beam and acquires an entire volume (14-26 cm in length) in a single, relatively slow gantry rotation.…”

Section: Iib Kilovoltage Cone-beam Ctmentioning

confidence: 99%

Quality assurance for image‐guided radiation therapy utilizing CT‐based technologies: A report of the AAPM TG‐179

et al. 2012

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“…Onboard kilovoltage (kV) cone-beam computed tomography (CBCT) systems installed on modern linear accelerators enable online image guidance and are most commonly used for 3D pretreatment patient setup verification and localization. 1,2 This capability allows the delivery of conformal dose distributions with high accuracy even for hypofractionated regimes, e.g., stereotactic body radiotherapy (SBRT). 3 CBCT images can potentially be used for routine dose recalculation during the course of treatment, when plan reoptimization is desirable due to large anatomy changes or motion.…”

Section: Introductionmentioning

confidence: 99%

Validation of a deformable image registration technique for cone beam CT‐based dose verification

et al. 2015

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Purpose: As radiation therapy evolves toward more adaptive techniques, image guidance plays an increasingly important role, not only in patient setup but also in monitoring the delivered dose and adapting the treatment to patient changes. This study aimed to validate a method for evaluation of delivered intensity modulated radiotherapy (IMRT) dose based on multimodal deformable image registration () for prostate treatments. Methods: A pelvic phantom was scanned with CT and cone-beam computed tomography (CBCT). Both images were digitally deformed using two realistic patient-based deformation fields. The original CT was then registered to the deformed CBCT resulting in a secondary deformed CT. The registration quality was assessed as the ability of the  method to recover the artificially induced deformations. The primary and secondary deformed CT images as well as vector fields were compared to evaluate the efficacy of the registration method and it's suitability to be used for dose calculation. , a free and open source software was used for deformable image registration. A B-spline algorithm with optimized parameters was used to achieve the best registration quality. Geometric image evaluation was performed through voxel-based Hounsfield unit (HU) and vector field comparison. For dosimetric evaluation, IMRT treatment plans were created and optimized on the original CT image and recomputed on the two warped images to be compared. The dose volume histograms were compared for the warped structures that were identical in both warped images. This procedure was repeated for the phantom with full, half full, and empty bladder. Results: The results indicated mean HU differences of up to 120 between registered and ground-truth deformed CT images. However, when the CBCT intensities were calibrated using a region of interest (ROI)-based calibration curve, these differences were reduced by up to 60%. Similarly, the mean differences in average vector field lengths decreased from 10.1 to 2.5 mm when CBCT was calibrated prior to registration. The results showed no dependence on the level of bladder filling. In comparison with the dose calculated on the primary deformed CT, differences in mean dose averaged over all organs were 0.2% and 3.9% for dose calculated on the secondary deformed CT with and without CBCT calibration, respectively, and 0.5% for dose calculated directly on the calibrated CBCT, for the full-bladder scenario. Gamma analysis for the distance to agreement of 2 mm and 2% of prescribed dose indicated a pass rate of 100% for both cases involving calibrated CBCT and on average 86% without CBCT calibration. Conclusions: Using deformable registration on the planning CT images to evaluate the IMRT dose based on daily CBCTs was found feasible. The proposed method will provide an accurate dose distribution using planning CT and pretreatment CBCT data, avoiding the additional uncertainties introduced by CBCT inhomogeneity and artifacts. This is a necessary initial step toward future imageguided adaptive ...

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Correction of patient positioning errors based on in-line cone beam CTs: clinical implementation and first experiences

Cited by 88 publications

References 21 publications

Late treatment with imatinib mesylate ameliorates radiation-induced lung fibrosis in a mouse model

Late treatment with imatinib mesylate ameliorates radiation-induced lung fibrosis in a mouse model

Quality assurance for image‐guided radiation therapy utilizing CT‐based technologies: A report of the AAPM TG‐179

Validation of a deformable image registration technique for cone beam CT‐based dose verification

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