Impact of intrafraction changes in delivered dose of the day for prostate cancer patients treated with stereotactic body radiotherapy via MR-Linac

Dang, Jennifer; Li, Winnie; Navarro, I.; Winter, Jeff; Malkov, Victor; Berlín, Alejandro; Catton, Charles; Padayachee, Jerusha; Raman, Srinivas; Warde, Padraig; Chung, Peter

doi:10.1016/j.tipsro.2022.08.005

Cited by 3 publications

(3 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similarly Dang et al. found that intra-fraction motion caused a statistically significant increase in the bladder D5cc dose ( 70 ). While the primary focus of this study was to reconstruct the daily delivered dose to the prostate, it is our hypothesis that the proposed intra-fraction re-planning workflow will also reduce the degradation in OAR sparing caused by intra-fraction motion.…”

Section: Discussionmentioning

confidence: 92%

“…Brennan et al found that urethral sparing was achieved in 92% of fractions as defined in the pre MRI scan but that number degraded to 66% of fractions meeting the same dosimetric constraint on the post MRI image (69). Similarly Dang et al found that intra-fraction motion caused a statistically significant increase in the bladder D5cc dose (70). While the primary focus of this study was to reconstruct the daily delivered dose to the prostate, it is our hypothesis that the proposed intra-fraction re-planning workflow will also reduce the degradation in OAR sparing caused by intrafraction motion.…”

Section: Discussionmentioning

confidence: 98%

See 1 more Smart Citation

Simulating an intra-fraction adaptive workflow to enable PTV margin reduction in MRIgART volumetric modulated arc therapy for prostate SBRT

Snyder,

Smith,

Aubin

et al. 2024

Front. Oncol.

View full text Add to dashboard Cite

PurposeThis study simulates a novel prostate SBRT intra-fraction re-optimization workflow in MRIgART to account for prostate intra-fraction motion and evaluates the dosimetric benefit of reducing PTV margins.Materials and methodsVMAT prostate SBRT treatment plans were created for 10 patients using two different PTV margins, one with a 5 mm margin except 3 mm posteriorly (standard) and another using uniform 2 mm margins (reduced). All plans were prescribed to 36.25 Gy in 5 fractions and adapted onto each daily MRI dataset. An intra-fraction adaptive workflow was simulated for the reduced margin group by synchronizing the radiation delivery with target position from cine MRI imaging. Intra-fraction delivered dose was reconstructed and prostate DVH metrics were evaluated under three conditions for the reduced margin plans: Without motion compensation (no-adapt), with a single adapt prior to treatment (ATP), and lastly for intra-fraction re-optimization during delivery (intra). Bladder and rectum DVH metrics were compared between the standard and reduced margin plans.ResultsAs expected, rectum V18 Gy was reduced by 4.4 ± 3.9%, D1cc was reduced by 12.2 ± 6.8% (3.4 ± 2.3 Gy), while bladder reductions were 7.8 ± 5.6% for V18 Gy, and 9.6 ± 7.3% (3.4 ± 2.5 Gy) for D1cc for the reduced margin reference plans compared to the standard PTV margin. For the intrafraction replanning approach, average intra-fraction optimization times were 40.0 ± 2.9 seconds, less than the time to deliver one of the four VMAT arcs (104.4 ± 9.3 seconds) used for treatment delivery. When accounting for intra-fraction motion, prostate V36.25 Gy was on average 96.5 ± 4.0%, 99.1 ± 1.3%, and 99.6 ± 0.4 for the non-adapt, ATP, and intra-adapt groups, respectively. The minimum dose received by the prostate was less than 95% of the prescription dose in 84%, 36%, and 10% of fractions, for the non-adapt, ATP, and intra-adapt groups, respectively.ConclusionsIntra-fraction re-optimization improves prostate coverage, specifically the minimum dose to the prostate, and enables PTV margin reduction and subsequent OAR sparing. Fast re-optimizations enable uninterrupted treatment delivery.

show abstract

Section: Discussionmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 98%

Simulating an intra-fraction adaptive workflow to enable PTV margin reduction in MRIgART volumetric modulated arc therapy for prostate SBRT

Snyder,

Smith,

Aubin

et al. 2024

Front. Oncol.

View full text Add to dashboard Cite

show abstract

“…It usually involves a combination of deformation, translation, and rotation. In particular OAR deformation can impact dose delivered to the OAR 31 . Still, deformation can be imaged intra‐fractionally, for example, using fast volumetric US systems, 32 and with information about tissue deformation it is straight forward to apply our approach for deformation of PTV and OARs.…”

Section: Discussionmentioning

confidence: 99%

Towards fast adaptive replanning by constrained reoptimization for intra‐fractional non‐periodic motion during robotic SBRT

Gerlach

Hofmann²,

Fürweger³

et al. 2023

Medical Physics

View full text Add to dashboard Cite

Background Periodic and slow target motion is tracked by synchronous motion of the treatment beams in robotic stereotactic body radiation therapy (SBRT). However, spontaneous, non‐periodic displacement or drift of the target may completely change the treatment geometry. Simple motion compensation is not sufficient to guarantee the best possible treatment, since relative motion between the target and organs at risk (OARs) can cause substantial deviations of dose in the OARs. This is especially evident when considering the temporally heterogeneous dose delivery by many focused beams which is typical for robotic SBRT. Instead, a reoptimization of the remaining treatment plan after a large target motion during the treatment could potentially reduce the actually delivered dose to OARs and improve target coverage. This reoptimization task, however, is challenging due to time constraints and limited human supervision. Purpose To study the detrimental effect of spontaneous target motion relative to surrounding OARs on the delivered dose distribution and to analyze how intra‐fractional constrained replanning could improve motion compensated robotic SBRT of the prostate. Methods We solve the inverse planning problem by optimizing a linear program. When considering intra‐fractional target motion resulting in a change of geometry, we adapt the linear program to account for the changed dose coefficients and delivered dose. We reduce the problem size by only reweighting beams from the reference treatment plan without motion. For evaluation we simulate target motion and compare our approach for intra‐fractional replanning to the conventional compensation by synchronous beam motion. Results are generated retrospectively on data of 50 patients. Results Our results show that reoptimization can on average retain or improve coverage in case of target motion compared to the reference plan without motion. Compared to the conventional compensation, coverage is improved from 87.83 % to 94.81 % for large target motion. Our approach for reoptimization ensures fixed upper constraints on the dose even after motion, enabling safer intra‐fraction adaption, compared to conventional motion compensation where overdosage in OARs can lead to 21.79 % higher maximum dose than planned. With an average reoptimization time of 6 s for 200 reoptimized beams our approach shows promising performance for intra‐fractional application. Conclusions We show that intra‐fractional constrained reoptimization for adaption to target motion can improve coverage compared to the conventional approach of beam translation while ensuring that upper dose constraints on VOIs are not violated.

show abstract

Monitoring Intrafraction Motion of the Prostate During Radiation Therapy: Suggested Practice Points From a Focused Review

Shimomura,

Wu,

Rusu

et al. 2024

Practical Radiation Oncology

View full text Add to dashboard Cite

Impact of intrafraction changes in delivered dose of the day for prostate cancer patients treated with stereotactic body radiotherapy via MR-Linac

Cited by 3 publications

References 29 publications

Simulating an intra-fraction adaptive workflow to enable PTV margin reduction in MRIgART volumetric modulated arc therapy for prostate SBRT

Simulating an intra-fraction adaptive workflow to enable PTV margin reduction in MRIgART volumetric modulated arc therapy for prostate SBRT

Towards fast adaptive replanning by constrained reoptimization for intra‐fractional non‐periodic motion during robotic SBRT

Monitoring Intrafraction Motion of the Prostate During Radiation Therapy: Suggested Practice Points From a Focused Review

Contact Info

Product

Resources

About