In Silico Trial of Computed Tomography-Guided Stereotactic Adaptive Radiation Therapy (CT-STAR) for the Treatment of Abdominal Oligometastases

Schiff, Joshua; Stowe, H.B.; Price, Alex; Laugeman, Eric; Hatscher, Casey; Hugo, Geoffrey D.; Badiyan, Shahed N.; Kim, Hyun; Robinson, C.G.; Henke, Lauren E.

doi:10.1016/j.ijrobp.2022.06.078

Cited by 10 publications

(22 citation statements)

References 30 publications

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“…Each plan utilized a 5 mm isotropic PTV margin from the GTV or CTV. For CT‐STAR planning, PTV coverage can be sacrificed in order to avoid nearby Organs at Risk (OARs) 5 . Therefore, sharp dose gradients often are closer, or within the target, than typical SBRT planning.…”

Section: Discussionmentioning

confidence: 99%

“…12 CT-STAR was demonstrated to account for interfractional anatomic changes. 2,5,20,21 However, intrafractional respiratory motion management on the Ethos system has been a practical challenge due to the closedbore ring gantry LINAC and offset kV panel of the Ethos system. 22 To the authors'knowledge,there is limited literature available on the topic of intra-fractional respiratory motion management with a surface imaging solution for Ethos stereotactic body adaptive radiotherapy.…”

Section: Introductionmentioning

confidence: 99%

“…High‐quality cone beam computed tomography (CBCT) and artificial intelligence (AI)‐enhanced adaptive planning techniques on the Ethos System (Varian Medical Systems, CA) allow for inter‐fractional motion management via CBCT‐guided stereotactic adaptive radiotherapy (CT‐STAR) 1–4 . The inter‐fractional management has been demonstrated in silico and/or clinically in a variety of disease sites 2,5–7 . In contrast to inter‐fractional changes, intra‐fractional changes require continual management during each fraction of the treatment course 8 .…”

Section: Introductionmentioning

confidence: 99%

“…CT‐STAR was demonstrated to account for inter‐fractional anatomic changes 2,5,20,21 . However, intra‐fractional respiratory motion management on the Ethos system has been a practical challenge due to the closed‐bore ring gantry LINAC and offset kV panel of the Ethos system 22 .…”

Section: Introductionmentioning

confidence: 99%

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Feasibility of surface‐guidance combined with CBCT for intra‐fractional breath‐hold motion management during Ethos RT

Kim,

Laugeman,

Kiser

et al. 2024

J Applied Clin Med Phys

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PurposeHigh‐quality CBCT and AI‐enhanced adaptive planning techniques allow CBCT‐guided stereotactic adaptive radiotherapy (CT‐STAR) to account for inter‐fractional anatomic changes. Studies of intra‐fractional respiratory motion management with a surface imaging solution for CT‐STAR have not been fully conducted. We investigated intra‐fractional motion management in breath‐hold Ethos‐based CT‐STAR and CT‐SBRT (stereotactic body non‐adaptive radiotherapy) using optical surface imaging combined with onboard CBCTs.MethodsTen cancer patients with mobile lower lung or upper abdominal malignancies participated in an IRB‐approved clinical trial (Phase I) of optical surface image‐guided Ethos CT‐STAR/SBRT. In the clinical trial, a pre‐configured gating window (± 2 mm in AP direction) on optical surface imaging was used for manually triggering intra‐fractional CBCT acquisition and treatment beam irradiation during breath‐hold (seven patients for the end of exhalation and three patients for the end of inhalation). Two inter‐fractional CBCTs at the ends of exhalation and inhalation in each fraction were acquired to verify the primary direction and range of the tumor/imaging‐surrogate (donut‐shaped fiducial) motion. Intra‐fractional CBCTs were used to quantify the residual motion of the tumor/imaging‐surrogate within the pre‐configured breath‐hold window in the AP direction. Fifty fractions of Ethos RT were delivered under surface image‐guidance: Thirty‐two fractions with CT‐STAR (adaptive RT) and 18 fractions with CT‐SBRT (non‐adaptive RT). The residual motion of the tumor was quantified by determining variations in the tumor centroid position. The dosimetric impact on target coverage was calculated based on the residual motion.ResultsWe used 46 fractions for the analysis of intra‐fractional residual motion and 43 fractions for the inter‐fractional motion analysis due to study constraints. Using the image registration method, 43 pairs of inter‐fractional CBCTs and 100 intra‐fractional CBCTs attached to dose maps were analyzed. In the motion range study (image registration) from the inter‐fractional CBCTs, the primary motion (mean ± std) was 16.6 ± 9.2 mm in the SI direction (magnitude: 26.4 ± 11.3 mm) for the tumors and 15.5 ± 7.3 mm in the AP direction (magnitude: 20.4 ± 7.0 mm) for the imaging‐surrogate, respectively. The residual motion of the tumor (image registration) from intra‐fractional breath‐hold CBCTs was 2.2 ± 2.0 mm for SI, 1.4 ± 1.4 mm for RL, and 1.3 ± 1.3 mm for AP directions (magnitude: 3.5 ± 2.1 mm). The ratio of the actual dose coverage to 99%, 90%, and 50% of the target volume decreased by 0.95 ± 0.11, 0.96 ± 0.10, 0.99 ± 0.05, respectively. The mean percentage of the target volume covered by the prescribed dose decreased by 2.8 ± 4.4%.ConclusionWe demonstrated the intra‐fractional motion‐managed treatment strategy in breath‐hold Ethos CT‐STAR/SBRT using optical surface imaging and CBCT. While the controlled residual tumor motion measured at 3.5 mm exceeded the predetermined setup value of 2 mm, it is important to note that this motion still fell within the clinically acceptable range defined by the PTV margin of 5 mm. Nonetheless, additional caution is needed with intra‐fractional motion management in breath‐hold Ethos CT‐STAR/SBRT using optical surface imaging and CBCT.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Feasibility of surface‐guidance combined with CBCT for intra‐fractional breath‐hold motion management during Ethos RT

Kim,

Laugeman,

Kiser

et al. 2024

J Applied Clin Med Phys

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“…However, MRI-guided radiotherapy solutions are expensive, rarely available, and require dedicated education and installations for their use (Fast et al 2019, Rosenberg et al 2019, Witt et al 2020. On the other hand, CBCT-guided stereotactic online-adaptive radiotherapy (CBCT-STAR) has been harnessed and recently implemented thanks to a new ring gantry linear accelerator equipped with a fast and high-quality volumetric CBCT imaging system and an on-board treatment planning system (ETHOS; Varian Medical Systems, Palo Alto, Calif., USA) (Archambault et al 2020, Sibolt et al 2021, Schiff et al 2022a, 2022b. In adaptive workflows based on the CBCT acquired at each treatment sessions, artificial intelligence algorithms allow fast automatic delineation of organs at risk (OARs), called influencers, automatic influencers-guided propagation of target volumes, and automatic daily plan re-computation (Archambault et al 2020, Sibolt et al 2021.…”

Section: Introductionmentioning

confidence: 99%

Markerless liver online adaptive stereotactic radiotherapy: feasibility analysis

Pierrard,

Deheneffe,

Dechambre

et al. 2024

Phys. Med. Biol.

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Objective Radio-opaque markers are recommended for image-guided radiotherapy in liver stereotactic ablative radiotherapy (SABR), but their implantation is invasive. We evaluate in this in-silico study the feasibility of cone-beam computed tomography-guided stereotactic online-adaptive radiotherapy (CBCT-STAR) to propagate the target volumes without implanting radio-opaque markers and assess its consequence on the margin that should be used in that context. Approach An emulator of a CBCT-STAR-dedicated treatment planning system was used to generate plans for 32 liver SABR patients. Three target volume propagation strategies were compared, analysing the volume difference between the GTVPropagated and the GTVConventional, and the vector lengths between their centres of mass (lCoM). These propagation strategies were: (1) structure-guided deformable registration with deformable GTV propagation; (2) rigid registration with rigid GTV propagation; and (3) image-guided deformable registration with rigid GTV propagation. Adaptive margin calculation integrated propagation errors, while interfraction position errors were removed. Scheduled plans (PlanNon-adaptive) and daily-adapted plans (PlanAdaptive) were compared for each treatment fraction.Main results The image-guided deformable registration with rigid GTV propagation was the best propagation strategy regarding to lCoM values (mean: 4.3 +/- 2.1 mm) and volume preservation between GTVPropagated and GTVConventional. This resulted in a planning target volume (PTV) margin increase (+69.1% in volume on average). Online adaptation (PlanAdaptive) reduced the violation rate of the most important dose constraints (“priority 1 constraints”, 4.2 versus 0.9 %, respectively; p < 0.001) and even improved target volume coverage compared to non-adaptive plans (PlanNon-adaptive). SignificanceMarkerless CBCT-STAR for liver tumours is feasible using Image-guided deformable registration with rigid GTV propagation. Despite the cost in terms of PTV volumes, daily adaptation reduces constraints violation and restores target volumes coverage.

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Prospective In Silico Evaluation of Cone-Beam Computed Tomography-Guided StereoTactic Adaptive Radiation Therapy (CT-STAR) for the Ablative Treatment of Ultracentral Thoracic Disease

Schiff¹,

Laugeman²,

Stowe³

et al. 2023

Advances in Radiation Oncology

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In Silico Trial of Computed Tomography-Guided Stereotactic Adaptive Radiation Therapy (CT-STAR) for the Treatment of Abdominal Oligometastases

Cited by 10 publications

References 30 publications

Feasibility of surface‐guidance combined with CBCT for intra‐fractional breath‐hold motion management during Ethos RT

Feasibility of surface‐guidance combined with CBCT for intra‐fractional breath‐hold motion management during Ethos RT

Markerless liver online adaptive stereotactic radiotherapy: feasibility analysis

Prospective In Silico Evaluation of Cone-Beam Computed Tomography-Guided StereoTactic Adaptive Radiation Therapy (CT-STAR) for the Ablative Treatment of Ultracentral Thoracic Disease

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