Effect of mid-scan breathing changes on quality of 4DCT using a commercial phase-based sorting algorithm

Noël, C.; Parikh, Parag J.

doi:10.1118/1.3574872

Cited by 13 publications

(18 citation statements)

References 47 publications

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“…For this simulation we use Eq. (28) = 1, 6, 10, 30 s), which is effectively changing the dose rate (MU/min) for a given segment with fixed MU, and number of fractions (K = 1, 4, 30). Figure 1 shows the results of one simulation of multiple deliveries for a fixed time t. Figure 1(a) shows the result for perfect repeated deliveries with fixed t 0 .…”

Section: Iic4 Imrt Delivery Time With Irregular Breathing Cyclementioning

confidence: 99%

Dynamically accumulated dose and 4D accumulated dose for moving tumors

Zhang

et al. 2012

Medical Physics

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Purpose: The purpose of this work was to investigate the relationship between dynamically accumulated dose (dynamic dose) and 4D accumulated dose (4D dose) for irradiation of moving tumors, and to quantify the dose uncertainty induced by tumor motion. Methods: The authors established that regardless of treatment modality and delivery properties, the dynamic dose will converge to the 4D dose, instead of the 3D static dose, after multiple deliveries. The bounds of dynamic dose, or the maximum estimation error using 4D or static dose, were established for the 4D and static doses, respectively. Numerical simulations were performed (1) to prove the principle that for each phase, after multiple deliveries, the average number of deliveries for any given time converges to the total number of fractions (K) over the number of phases (N); (2) to investigate the dose difference between the 4D and dynamic doses as a function of the number of deliveries for deliveries of a "pulsed beam"; and (3) to investigate the dose difference between 4D dose and dynamic doses as a function of delivery time for deliveries of a "continuous beam." A Poisson model was developed to estimate the mean dose error as a function of number of deliveries or delivered time for both pulsed beam and continuous beam. Results:The numerical simulations confirmed that the number of deliveries for each phase converges to K/N, assuming a random starting phase. Simulations for the pulsed beam and continuous beam also suggested that the dose error is a strong function of the number of deliveries and/or total deliver time and could be a function of the breathing cycle, depending on the mode of delivery. The Poisson model agrees well with the simulation. Conclusions: Dynamically accumulated dose will converge to the 4D accumulated dose after multiple deliveries, regardless of treatment modality. Bounds of the dynamic dose could be determined using quantities derived from 4D doses, and the mean dose difference between the dynamic dose and 4D dose as a function of number of deliveries and/or total deliver time was also established.

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Section: Iic4 Imrt Delivery Time With Irregular Breathing Cyclementioning

confidence: 99%

Dynamically accumulated dose and 4D accumulated dose for moving tumors

Zhang

et al. 2012

Medical Physics

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“…It is not clear why this relationship was absent for phase-binned image sets; however, the complexities of helical scan acquisition and image reconstruction are likely factors. A more systematic experimental approach may clarify the relationship between distortions and breathing irregularities, as done by Noel et al 18 Even so, it can be seen in Fig. 4 that there was a general increase in distortions with more irregular waveforms.…”

Section: After Experimental and Clinical Evaluation Of Both Amplitudementioning

confidence: 84%

“…Figure 1 An in-house developed programmable motion phantom 17 (Washington University 4D phantom, St. Louis, MO) was utilized for the phantom study. 18 The motorized phantom was comprised of a dynamic three-dimensional imaging stage to hold an imaged object and a separate one-dimensional motion axis for attaching a respiratory surrogate to simulate a synchronized breathing signal. The system has been previously tested and shown to provide motion with submillimeter accuracy.…”

Section: Iic Amplitude-binning Algorithm For 4dct Image Reconstructionmentioning

confidence: 99%

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Clinical evaluations of an amplitude-based binning algorithm for 4DCT reconstruction in radiation therapy

Noël

Garcia-Ramirez

et al. 2012

Med. Phys.

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Overall, the amplitude-binning algorithm for 4DCT reconstruction reduced the severity of tumor distortion and image artifacts compared to the phase-binning algorithm. However, the full range of motion may not be characterized using amplitude-binning algorithms. Despite superior performance, amplitude binning can still be susceptible to motion artifacts caused by large variations in amplitude of respiratory waves.

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“…1). Four-dimensional CT ITVs from sinusoidal and irregular breathing patterns have been analyzed volumetrically and are reported in the literature, [1][2][3] as have CBCT ITVs from sinusoidal patterns. 2,4 However, the effect that irregular patterns have on CBCT ITVs has not yet been analyzed in 3D, only 2D, 5 and there have been FIG.…”

Section: Introductionmentioning

confidence: 99%

The effect of irregular breathing patterns on internal target volumes in four-dimensional CT and cone-beam CT images in the context of stereotactic lung radiotherapy

et al. 2013

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Strategies are needed to compensate for volume losses at the extremes of motion for both 4DCT MIP and CBCT images for larger and varied amplitudes, and for patterns with rest periods following expiration. Lesions moving greater than 2 cm would warrant larger treatment margins added to the 4DCT MIP ITV to account for the volume being under-represented at the extremes of motion. Lesions moving with a rest period following expiration would be better aligned using an edge-to-edge alignment technique. Sinusoidal patterns represented the ideal clinical scenario, reinforcing the importance of investigating clinically relevant motions and their effects on 4DCT MIP and CBCT volumes. Since most patients do not breathe sinusoidally this may lead to misinterpretation of previous studies using only sinusoidal motion.

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Effect of mid-scan breathing changes on quality of 4DCT using a commercial phase-based sorting algorithm

Abstract: This study suggests that basic breathing statistics can be used to quickly assess the quality of a 4DCT scan prior to image reconstruction. Such information can help give indication of the proper course of action when irregular breathing patterns are observed during CT scanning.

Cited by 13 publications

References 47 publications

Dynamically accumulated dose and 4D accumulated dose for moving tumors

Dynamically accumulated dose and 4D accumulated dose for moving tumors

Clinical evaluations of an amplitude-based binning algorithm for 4DCT reconstruction in radiation therapy

The effect of irregular breathing patterns on internal target volumes in four-dimensional CT and cone-beam CT images in the context of stereotactic lung radiotherapy

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