Planar IGRT dose reduction: A practical approach

Block, Alec M.; Luce, J.; Lin, Jeffrey; Hoggarth, Mark A.; Roeske, John C.

doi:10.1016/j.prro.2014.09.008

Cited by 2 publications

(2 citation statements)

References 28 publications

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“…Image quality of the X-ray images obtained with RTRT is different from that of images acquired using on-board imaging (OBI). For instance, typical settings for kV image acquisition in OBI for chest and abdomen are 10 mAs and 32 mAs, respectively [15], whereas the RTRT system makes use of pulsed fluoroscopy with up to about 0.5 mAs, with relatively large source-to-image distance (SID) of approximately 4 m. RTRT requires performance checks with sequential images obtained by pulsed fluoroscopy in a model clinical situation because image quality and search images of fiducial markers vary from image to image, according to respiratory motion. To date, few reports have quantitatively evaluated the image recognition performance of multiple fiducial markers that can be used for RTRT.…”

Section: Introductionmentioning

confidence: 99%

Quantitative evaluation of image recognition performance of fiducial markers in real-time tumor-tracking radiation therapy

et al. 2019

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To quantitatively evaluate and compare the image recognition performance of multiple fiducial markers available in real-time tumor-tracking radiation therapy (RTRT). Methods: Clinically available markers including sphere shape, coil shape, cylinder shape, line shape, and ball shape (folded line shape) were evaluated in liver and lung models of RTRT. Maximum thickness of the polymethyl metacrylate (PMMA) phantom that could automatically recognize the marker was determined by template-pattern matching. Image registration accuracy of the fiducial marker was determined using liver RTRT model. Lung RTRT was mimicked with an anthropomorphic chest phantom and a one-dimensional motion stage in order to simulate marker motion in heterogeneous fluoroscopic images. The success or failure of marker tracking and image registration accuracy for the lung model were evaluated in the same manner as that for the liver model. Results: All fiducial markers except for line shape and coil shape of thinner diameter were recognized by the PMMA phantom, which is assumed to have the typical thickness of an abdomen, with twodimensional image registration accuracy of <2 pixels. Three-dimensional calculation error with the use of real-time stereoscopic fluoroscopy in RTRT was thought to be within 1 mm. In the evaluation using the lung model, the fiducial markers were recognized stably with sufficient accuracy for clinical application. The same was true for the evaluation using the liver model. Conclusions: The image recognition performance of fiducial markers was quantified and compared. The results presented here may be useful for the selection of fiducial markers.

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Section: Introductionmentioning

confidence: 99%

Quantitative evaluation of image recognition performance of fiducial markers in real-time tumor-tracking radiation therapy

et al. 2019

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“…Based on a previous study, the additional dose to the skin (assuming 90 cm SSD) is approximately 1.022 mGy/s. 18 , 36 Although this additional dose may not be clinically significant, all efforts should be made to ensure that it is as low as reasonably possible and that the clinical benefits from MTT outweighs the additional dose. A final limitation is that all analysis was performed using simulated tumors that are spherical in shape.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Markerless Tumor Tracking Using the On-Board Imager of a Commercial Linear Accelerator Equipped With Fast-kV Switching Dual-Energy Imaging

Roeske

Mostafavi

Haytmyradov

et al. 2020

Advances in Radiation Oncology

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Purpose To describe and characterize fast-kV switching, dual-energy (DE) imaging implemented within the on-board imager of a commercial linear accelerator for markerless tumor tracking (MTT). Methods and Materials Fast-kV switching, DE imaging provides for rapid switching between programmed tube voltages (ie, 60 and 120 kVp) from one image frame to the next. To characterize this system, the weighting factor used for logarithmic subtraction and signal difference-to-noise ratio were analyzed as a function of time and frame rate. MTT was evaluated using a thorax motion phantom and fast kV, DE imaging was compared versus single energy (SE) imaging over 360 degrees of rotation. A template-based matching algorithm was used to track target motion on both DE and SE sequences. Receiver operating characteristics were used to compare tracking results for both modalities. Results The weighting factor was inversely related to frame rate and stable over time. After applying the frame rate–dependent weighting factor, the signal difference-to-noise ratio was consistent across all frame rates considered for simulated tumors ranging from 5 to 25 mm in diameter. An analysis of receiver operating characteristics curves showed improved tracking with DE versus SE imaging. The area under the curve for the 10-mm target ranged from 0.821 to 0.858 for SE imaging versus 0.968 to 0.974 for DE imaging. Moreover, the residual tracking errors for the same target size ranged from 2.02 to 2.18 mm versus 0.79 to 1.07 mm for SE and DE imaging, respectively. Conclusions Fast-kV switching, DE imaging was implemented on the on-board imager of a commercial linear accelerator. DE imaging resulted in improved MTT accuracy over SE imaging. Such an approach may have application for MTT of patients with lung cancer receiving stereotactic body radiation therapy, particularly for small tumors where MTT with SE imaging may fail.

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Planar IGRT dose reduction: A practical approach

Cited by 2 publications

References 28 publications

Quantitative evaluation of image recognition performance of fiducial markers in real-time tumor-tracking radiation therapy

Quantitative evaluation of image recognition performance of fiducial markers in real-time tumor-tracking radiation therapy

Characterization of Markerless Tumor Tracking Using the On-Board Imager of a Commercial Linear Accelerator Equipped With Fast-kV Switching Dual-Energy Imaging

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