Treating patients with real-time tumor tracking using the Vero gimbaled linac system: Implementation and first review

Depuydt, Tom; Poels, Kenneth; Verellen, Dirk; Engels, Benedikt; Collen, Christine; Buleteanu, M; Begin, Robbe Van den; Boussaer, M.; Duchateau, Michaël; Gevaert, Thierry; Storme, Guy; Ridder, Mark De

doi:10.1016/j.radonc.2014.05.017

Cited by 101 publications

(124 citation statements)

References 43 publications

Supporting

Mentioning

123

Contrasting

Order By: Relevance

“…1 for an Potential dosimetric benefits for lung SABR with MLC tracking and midV have been shown by quantifying a reduction in dose delivered to the OAR while maintaining the target dose coverage. For tracking, the 30% reduction in PTV found in this study is consistent in magnitude with the PTV reduction of 30.2% and 36% reported with the Cyberknife experience [29] and the Vero gimbal linac [7], respectively. This study was conducted in a clinically realistic scenario, in that the treatment workflow was followed and real patient motion trajectories applied, supporting clinical translation from benchtop to bedside of a prospective clinical trial for MLC tracking with implanted electromagnetic transponders (NCT02514512).…”

Section: Assessment Of Target Dose Coveragesupporting

confidence: 88%

“…The GTV was defined on the end-of-exhale phase, namely the GTVTRACK, to assure a proper localization and delineation of the tumour [7,[15][16][17]. Collimators were angled to have the leaf trajectory parallel to the superior-inferior motion (85/95°) [18].…”

Section: Treatment Planningmentioning

confidence: 99%

“…The prevalent approach, recommended by the ICRU 83, is to apply the Internal Treatment Volume (ITV)-based motion-inclusive method that enlarges the treatment fields to account for motion and uncertainty. Since dose to organs-at-risk (OAR) generally shows a relationship with toxicity [4], numerous strategies have been deployed to moderate unnecessary dose spillage such as treatment beam gating [5], adaptive couch tracking [6], adaptive real-time tumour tracking [7][8][9] and passive strategies such as the mid-ventilation (midV) planning treatment volume (PTV)-based approach [10].…”

mentioning

confidence: 99%

See 2 more Smart Citations

MLC tracking for lung SABR reduces planning target volumes and dose to organs at risk

Caillet

Keall

Colvill

et al. 2017

Radiotherapy and Oncology

View full text Add to dashboard Cite

Section: Assessment Of Target Dose Coveragesupporting

confidence: 88%

Section: Treatment Planningmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

MLC tracking for lung SABR reduces planning target volumes and dose to organs at risk

Caillet

Keall

Colvill

et al. 2017

Radiotherapy and Oncology

View full text Add to dashboard Cite

“…It does not affect patient comfort and has a minimal impact on treatment delivery time. Tumor tracking solutions for lung SBRT have been presented and evaluated for the robotic Cyberknife (Accuray Inc., Sunnyvale, CA, USA) 8 , 9 and the gimbaled Vero (Brainlab AG, Feldkirchen, Germany) machines 10 , 11 . Both machines are intentionally designed for tumor tracking by either allowing for moving the whole beam using a robotic arm or panning and tilting the beam utilizing gimbals.…”

Section: Introductionmentioning

confidence: 99%

Real‐time 4D dose reconstruction for tracked dynamic MLC deliveries for lung SBRT

et al. 2016

View full text Add to dashboard Cite

PurposeThis study provides a proof of concept for real‐time 4D dose reconstruction for lung stereotactic body radiation therapy (SBRT) with multileaf collimator (MLC) tracking and assesses the impact of tumor tracking on the size of target margins.MethodsThe authors have implemented real‐time 4D dose reconstruction by connecting their tracking and delivery software to an Agility MLC at an Elekta Synergy linac and to their in‐house treatment planning software (TPS). Actual MLC apertures and (simulated) target positions are reported to the TPS every 40 ms. The dose is calculated in real‐time from 4DCT data directly after each reported aperture by utilization of precalculated dose‐influence data based on a Monte Carlo algorithm. The dose is accumulated onto the peak‐exhale (reference) phase using energy‐mass transfer mapping. To investigate the impact of a potentially reducible safety margin, the authors have created and delivered treatment plans designed for a conventional internal target volume (ITV) + 5 mm, a midventilation approach, and three tracking scenarios for four lung SBRT patients. For the tracking plans, a moving target volume (MTV) was established by delineating the gross target volume (GTV) on every 4DCT phase. These were rigidly aligned to the reference phase, resulting in a unified maximum GTV to which a 1, 3, or 5 mm isotropic margin was added. All scenarios were planned for 9‐beam step‐and‐shoot IMRT to meet the criteria of RTOG 1021 (3 × 18 Gy). The GTV 3D center‐of‐volume shift varied from 6 to 14 mm.ResultsReal‐time dose reconstruction at 25 Hz could be realized on a single workstation due to the highly efficient implementation of dose calculation and dose accumulation. Decreased PTV margins resulted in inadequate target coverage during untracked deliveries for patients with substantial tumor motion. MLC tracking could ensure the GTV target dose for these patients. Organ‐at‐risk (OAR) doses were consistently reduced by decreased PTV margins. The tracked MTV + 1 mm deliveries resulted in the following OAR dose reductions: lung V 20 up to 3.5%, spinal cord D 2 up to 0.9 Gy/Fx, and proximal airways D 2 up to 1.4 Gy/Fx.ConclusionsThe authors could show that for patient data at clinical resolution and realistic motion conditions, the delivered dose could be reconstructed in 4D for the whole lung volume in real‐time. The dose distributions show that reduced margins yield lower doses to healthy tissue, whilst target dose can be maintained using dynamic MLC tracking.

show abstract

“…A real‐time tumor tracking system which uses a gimbaled linac, the Vero system (Brainlab AG, Feldkirchen, Germany), (15) is equipped with a stereoscopic dual‐source kV X‐ray imaging system for patient positioning and image guidance for tracking (16) . In combination with the FBCT images and the treatment plan optimized based on the FBCT, the CBCT data obtained using this kV imaging system can, in principle, be used for adaptive radiotherapy purposes (i.e., treatment plan adaptation in reaction to potential changes in patient anatomy) 2 , 5 , 6 .…”

Section: Introductionmentioning

confidence: 99%

Dosimetric accuracy of the cone‐beam CT‐based treatment planning of the Vero system: a phantom study

Yohannes

Prasetio

Kallis

et al. 2016

J Applied Clin Med Phys

View full text Add to dashboard Cite

We report an investigation on the accuracy of dose calculation based on the cone‐beam computed tomography (CBCT) images of the nonbowtie filter kV imaging system of the Vero linear accelerator. Different sets of materials and tube voltages were employed to generate the Hounsfield unit lookup tables (HLUTs) for both CBCT and fan‐beam CT (FBCT) systems. The HLUTs were then implemented for the dose calculation in a treatment planning system (TPS). Dosimetric evaluation was carried out on an in‐house‐developed cube phantom that consists of water‐equivalent slabs and inhomogeneity inserts. Two independent dosimeters positioned in the cube phantom were used in this study for point‐dose and two‐dimensional (2D) dose distribution measurements. The differences of HLUTs from various materials and tube voltages in both CT systems resulted in differences in dose calculation accuracy. We found that the higher the tube voltage used to obtain CT images, the better the point‐dose calculation and the gamma passing rate of the 2D dose distribution agree to the values determined in the TPS. Moreover, the insert materials that are not tissue‐equivalent led to higher dose‐calculation inaccuracy. There were negligible differences in dosimetric evaluation between the CBCT‐ and FBCT‐based treatment planning if the HLUTs were generated using the tissue‐equivalent materials. In this study, the CBCT images of the Vero system from a complex inhomogeneity phantom can be applied for the TPS dose calculation if the system is calibrated using tissue‐equivalent materials scanned at high tube voltage (i.e., 120 kV).PACS number(s): 87.55.de, 87.56.Fc, 87.57.qp

show abstract

Treating patients with real-time tumor tracking using the Vero gimbaled linac system: Implementation and first review

Cited by 101 publications

References 43 publications

MLC tracking for lung SABR reduces planning target volumes and dose to organs at risk

MLC tracking for lung SABR reduces planning target volumes and dose to organs at risk

Real‐time 4D dose reconstruction for tracked dynamic MLC deliveries for lung SBRT

Dosimetric accuracy of the cone‐beam CT‐based treatment planning of the Vero system: a phantom study

Contact Info

Product

Resources

About