Mid-ventilation based PTV margins in Stereotactic Body Radiotherapy (SBRT): A clinical evaluation

Peulen, Heike M.U.; Belderbos, J.; Rossi, Maddalena; Sonke, Jan‐Jakob

doi:10.1016/j.radonc.2014.01.010

Cited by 66 publications

(58 citation statements)

References 24 publications

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“…First, all sources of uncertainties were identified and the systematic (R) and random (r) error components of each analysed step were quantified as described above. Secondly, the systematic and random components were combined in quadrature respectively to obtain the overall uncertainty, R T and r T , under the assumptions of Gaussian and uncorrelated errors [26,36,37]. The required GTV-PTV margin was then calculated according to 2.5ÁR T + 0.7Ár T [25], since clinically we aim for PTV coverage by the 95% isodose level and assuming a penumbra (r p ) of 3.2 mm.…”

Section: Combination Of Uncertainties Into a Treatment Marginmentioning

confidence: 99%

A comprehensive evaluation of treatment accuracy, including end-to-end tests and clinical data, applied to intracranial stereotactic radiotherapy

Seravalli

Haaren

Toorn

et al. 2015

Radiotherapy and Oncology

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Section: Combination Of Uncertainties Into a Treatment Marginmentioning

confidence: 99%

A comprehensive evaluation of treatment accuracy, including end-to-end tests and clinical data, applied to intracranial stereotactic radiotherapy

Seravalli

Haaren

Toorn

et al. 2015

Radiotherapy and Oncology

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“…A margin is then applied to allow for setup errors (usually 5 mm) to create the planning target volume (PTV). 34 Multiple treatment systems have been used to treat patients undergoing SABR. These include the robotic linac (CyberKnife®, Accuray, Sunnyvale, CA), conventional gantry-based linac (Elekta®, Stockholm, Sweden.…”

Section: Introductionmentioning

confidence: 99%

A systematic review of outcomes following stereotactic ablative radiotherapy in the treatment of early-stage primary lung cancer

Murray

Franks

Hanna

2017

The British Journal of Radiology

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Stereotactic ablative body radiotherapy (SABR) describes a radiotherapy (RT) technique where high doses of radiation are precisely delivered to an extracranial target within the body, using either a single fraction of RT or using multiple small numbers of fractions. SABR has now become the standard of care treatment for patients with early-stage non-small-cell lung cancer (NSCLC) for whom surgery is not appropriate. This systematic review considers the evidence supporting the use of SABR in early-stage NSCLC, reported toxicity rates, the use of SABR in centrally located NSCLC, the use of SABR as salvage therapy following surgery or RT, and future potential drug combinations with SABR.

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“…Peulen et al 38 have shown in a clinical study that the midV/midP approach in combination with online image‐guidance results in a high local control rate. High‐dose volumes were smaller for patients with substantial tumor motion and hence midV/midP must be considered an improvement over the conventional ITV approach.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2016

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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.

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Mid-ventilation based PTV margins in Stereotactic Body Radiotherapy (SBRT): A clinical evaluation

Cited by 66 publications

References 24 publications

A comprehensive evaluation of treatment accuracy, including end-to-end tests and clinical data, applied to intracranial stereotactic radiotherapy

A comprehensive evaluation of treatment accuracy, including end-to-end tests and clinical data, applied to intracranial stereotactic radiotherapy

A systematic review of outcomes following stereotactic ablative radiotherapy in the treatment of early-stage primary lung cancer

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

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