Evaluation of 3-D Versus 4-D Cone Beam CT Target Localization Methods for Free Breathing Liver Stereotactic Body Radiation Therapy

Li, W.; Kratz, Katherine; Pellizzari, Alana; Hsu, Janet; Becker, Nathan; Stanescu, T.; Kim, J.J.; Moseley, Douglas

doi:10.1016/j.ijrobp.2015.07.1014

Cited by 1 publication

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“…As a common clinical practice, automatic registration results are subject to validations and further adjustments by specialist clinicians or therapists. Based on the same 3D / 4D–CBCT acquisition and reconstruction protocols as in this study, the concordance between the observers’ (i.e., manual) and the automatic registrations with the liver contour was found to be within 0.75 mm, and the agreement was very high with Krippendorff’s alpha greater than 0.81 in all directions [24]. These preliminary results from Li et al .…”

Section: Discussionsupporting

confidence: 67%

“…This observation was consistent with the preliminary results of Li et al . including ten HCC patients, which concluded that target localization accuracy using the liver contour was found to be unaffected by large breathing amplitudes with 4D–CBCT as seen with 3D–CBCT [24]. A lobe–dependence was observed as the CC tumor prediction errors increased with increasing the tumor–to–diaphragm distance and the dependence reached significance after the removal of one outliner.…”

Section: Discussionmentioning

confidence: 99%

“…These preliminary results from Li et al . [24] suggested negligible observer’s bias on the final registrations following the automatic 3D and 4D–CBCT registration workflows, given that both images were reconstructed with the same projection data.…”

Section: Discussionmentioning

confidence: 99%

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Target localization of 3D versus 4D cone beam computed tomography in lipiodol-guided stereotactic radiotherapy of hepatocellular carcinomas

et al. 2017

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BackgroundAim of this study was to comparatively evaluate the accuracy of respiration–correlated (4D) and uncorrelated (3D) cone beam computed tomography (CBCT) in localizing lipiodolized hepatocellular carcinomas during stereotactic body radiotherapy (SBRT).Methods4D–CBCT scans of eighteen HCCs were acquired during free–breathing SBRT following trans–arterial chemo–embolization (TACE) with lipiodol. Approximately 1320 x–ray projections per 4D–CBCT were collected and phase–sorted into ten bins. A 4D registration workflow was followed to register the reconstructed time–weighted average CBCT with the planning mid–ventilation (MidV) CT by an initial bone registration of the vertebrae and then tissue registration of the lipiodol. For comparison, projections of each 4D–CBCT were combined to synthesize 3D–CBCT without phase–sorting. Using the lipiodolized tumor, uncertainties of the treatment setup estimated from the absolute and relative lipiodol position to bone were analyzed separately for 4D– and 3D–CBCT.ResultsQualitatively, 3D–CBCT showed better lipiodol contrast than 4D–CBCT primarily because of a tenfold increase of projections used for reconstruction. Motion artifact was observed to subside in 4D–CBCT compared to 3D–CBCT. Group mean, systematic and random errors estimated from 4D– and 3D–CBCT agreed to within 1 mm in the cranio–caudal (CC) and 0.5 mm in the anterior–posterior (AP) and left–right (LR) directions. Systematic and random errors are largest in the CC direction, amounting to 4.7 mm and 3.7 mm from 3D–CBCT and 5.6 mm and 3.8 mm from 4D–CBCT, respectively. Safety margin calculated from 3D–CBCT and 4D–CBCT differed by 2.1, 0.1 and 0.0 mm in the CC, AP, and LR directions.Conclusions3D–CBCT is an adequate alternative to 4D–CBCT when lipoid is used for localizing HCC during free–breathing SBRT. Similar margins are anticipated with 3D– and 4D–CBCT.

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Section: Discussionsupporting

confidence: 67%

Section: Discussionmentioning

confidence: 99%