Determination of Intrafraction Prostate Motion During External Beam Radiation Therapy With a Transperineal 4-Dimensional Ultrasound Real-Time Tracking System

Sihono, Dwi Seno Kuncoro; Ehmann, Michael; Heitmann, Sigrun; Swietochowski, Sandra von; Grimm, Maximilian; Boda-Heggemann, Judit; Lohr, Frank; Wenz, Frederik; Wertz, H.

doi:10.1016/j.ijrobp.2018.01.040

Cited by 41 publications

(38 citation statements)

References 27 publications

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“…Shihono et al (12) suggested the patient population-based margin according to the van Herk formula is as follows: 1.10 mm, 1.25 mm, and 1.33 mm in the SI, LR, and AP directions, respectively. They used the Clarity system just like our study.…”

Section: Discussionmentioning

confidence: 99%

“…A low α/β ratio of PCa has encouraged hypofractionation and stereotactic body radiation therapy (SBRT), or extreme hypofractionation, which is currently considered as a promising option of EBRT (3,4). While higher quality of positioning is required in SBRT to optimize treatments, it is known that organs in pelvis including prostate are shifting under the in uence of rectal volume, bladder volume, and change of muscle tension among other things (5)(6)(7)(8)(9)(10)(11)(12). These intrafractional uncertainties possibly affect the dose distributions (13,14).…”

Section: Introductionmentioning

confidence: 99%

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Injection of hydrogel spacer increased intrafractional prostate motion during volumetric modulated arc therapy-stereotactic body radiation therapy for prostate cancer

Sawayanagi¹,

Yamashita²,

Ogita³

et al. 2021

Preprint

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BackgroundThe aim of this study was to clarify the association between intrafractional prostate shift and hydrogel spacer.MethodsThirty-eight patients who received definitive volumetric modulated arc therapy (VMAT)-stereotactic body radiation therapy (SBRT) for prostate cancer with prostate motion monitoring in our institution in 2018–2019 were retrospectively evaluated. In order to move the rectum away from the prostate, hydrogel spacer (SpaceOAR system, Boston Scientific, Marlborough, the United States) injection was proposed to the patients as an option in case of meeting the indication of use. We monitored intrafractional prostate motion by using a 4-dimensional (4D) transperineal ultrasound (US) device: the Clarity 4D ultrasound system (Elekta AB). The deviation of the prostate was monitored in each direction: superior-inferior (SI), left-right (LR), and anterior-posterior (AP). We also calculated the vector length (VL). The maximum intrafractional displacement (MID) per fraction for each direction was detected and mean of MIDs was calculated per patient. The MIDs in the non-spacer group and the spacer group were compared using the unpaired t-test.ResultsWe reviewed 33 fractions in eight patients as the spacer group and 148 fractions in 30 patients as the non-spacer group. The superior MID was 0.47 ± 0.07 (mean ± SE) mm vs. 0.97 ± 0.24 mm (P = 0.014), the inferior MID was 1.07 ± 0.11 mm vs. 1.03 ± 0.25 mm (P = 0.88), the left MID was 0.74 ± 0.08 mm vs. 0.87 ± 0.27 mm (P = 0.55), the right MID was 0.67 ± 0.08 mm vs. 0.92 ± 0.21 mm (P = 0.17), the anterior MID was 0.45 ± 0.06 mm vs. 1.16 ± 0.35 mm (P = 0.0023), and the posterior MID was 1.57 ± 0.17 mm vs. 1.37 ± 0.22 mm (P = 0.56) in the non-spacer group and the spacer group, respectively. The max of VL was 2.24 ± 0.19 mm vs. 2.89 ± 0.62 mm (P = 0.19), respectively.ConclusionsOur findings suggest that intrafractional prostate motion during VMAT-SBRT was larger in patients with hydrogel spacer injection in the superior and anterior directions.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Injection of hydrogel spacer increased intrafractional prostate motion during volumetric modulated arc therapy-stereotactic body radiation therapy for prostate cancer

Sawayanagi¹,

Yamashita²,

Ogita³

et al. 2021

Preprint

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“…For example, beam delivery is halted when the shift at a time point exceeds a pre-defined intervention threshold (Lovelock et al, 2015). For each patient, internal organ motion may change from fraction to fraction or even from dataset to dataset within the same treatment fraction (Azcona et al, 2013;Li et al, 2013;Xie et al, 2008), so a predefined threshold may not be suitable to compensate for internal changes and inevitably lead to residual motion (Ballhausen et al, 2015;George et al, 2006;Sihono et al, 2018). Of course, it is reasonable to narrow the threshold in order to minimize target motion relative to a static treatment beam, especially in the setting of stereotactic body radiation therapy (SBRT) with tight margins.…”

Section: Introductionmentioning

confidence: 99%

Quantifying intra-fractional prostate motion trajectory for establishing a new gating strategy: a preliminary study

Gao

Zhao

Gao

et al. 2020

Journal of Radiation Research and Applied Sciences

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Background: Existing gated delivery methods adopting predefined intervention thresholds, and better delivery accuracy comes at the expense of lower therapeutic efficiency. So we present a new gating strategy based on trajectory quantification and pattern discrimination. Material and methods: 1265 real-time ultrasound monitoring trajectories of 61 prostate cancer patients were retrospectively analyzed. The trajectories included four typical patterns: stable target at baseline, transient excursion, continuous drift, and persistent excursion. Trajectories were randomly sampled to train a discriminant model that utilizes a sliding window approach with a 30-s window. The discriminant accuracy and receiver operating characteristic (ROC) curve were analyzed to assess the model's performance. Results:The discriminant model to identify intra-fractional motion patterns was successfully trained. The model had statistical significance (p < 0.001) and correctly classified 94.0% of trajectories in the time window. The area under the ROC curve, sensitivity, and specificity were all greater than 0.80 for different motion patterns. Conclusion: As an essential component of the new gating strategy, trajectory quantification makes it possible to automatically discriminate intra-fractional motion patterns; pattern discrimination further allows active guidance for subsequent interventions. This preliminary work has shown promise in delivering radiotherapy accurately and cost-effectively.

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“…Generally, the recording of the prostate position by 4D ultrasound [11] or kV-imaging [12, 13] during a fraction has received some interest in recent years and is a natural extension of these techniques from inter-fraction position verification and correction to online intra-fraction monitoring and adaption. The hope is, e.g.…”

Section: Introductionmentioning

confidence: 99%

Dosimetric impact of intrafraction motion on boosts on intraprostatic lesions: a simulation based on actual motion data from real time ultrasound tracking

Ballhausen

Reiner

et al. 2019

Radiat Oncol

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Background Intrafraction motion is particularly problematic in case of small target volumes and narrow margins. Here we simulate the dose coverage of intraprostatic lesions (IPL) by simultaneous integrated boosts (SIB). For this purpose, we use a large sample of actual intrafraction motion data. Methods Fifty-three h of intra-fraction motion of the prostate were recorded in real-time by 4D ultrasound (4DUS) during 720 fractions in 28 patients. We simulate spherical IPLs with 3, 5, and 7 mm radius and matching spherical SIBs with 0, 2, and 5 mm safety margins. The volumetric overlap between IPLs and SIBs is calculated. Dose volume histograms (DVH) are estimated by Monte Carlo simulation. Results On average, the distance of the prostate was 1.3 mm from its initial position over all fractions and patients. Average volumetric overlap was 73, 82, and 87% of IPL volume in case of 3, 5, and 7 mm IPLs and SIBs without safety margins. These improved to 95% or more in case of 2 mm safety margins and 98% or more in case of 5 mm safety margins. DVHs showed that 80% of the IPL volume received 60, 72, and 79% of maximum dose in case of 3, 5, and 7 mm IPLs and SIBs without safety margins. These improved to 94% or more given moderately sized safety margins of 2 mm. Conclusions On average over all fractions and patients, the dose coverage would have been acceptable even for small target volumes such as IPLs of radius 3 to 7 mm and narrow fields. Moderate safety margins of 2 mm could have ensured a delivery of 90% or more of the SIB dose to the IPL. In this case, SIB volume would have been considerably larger than IPL volume, but still considerably smaller than the overall PTV of the prostate. Electronic supplementary material The online version of this article (10.1186/s13014-019-1285-1) contains supplementary material, which is available to authorized users.

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Determination of Intrafraction Prostate Motion During External Beam Radiation Therapy With a Transperineal 4-Dimensional Ultrasound Real-Time Tracking System

Cited by 41 publications

References 27 publications

Injection of hydrogel spacer increased intrafractional prostate motion during volumetric modulated arc therapy-stereotactic body radiation therapy for prostate cancer

Injection of hydrogel spacer increased intrafractional prostate motion during volumetric modulated arc therapy-stereotactic body radiation therapy for prostate cancer

Quantifying intra-fractional prostate motion trajectory for establishing a new gating strategy: a preliminary study

Dosimetric impact of intrafraction motion on boosts on intraprostatic lesions: a simulation based on actual motion data from real time ultrasound tracking

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