Brain stereotactic radiosurgery using MR‐guided online adaptive planning for daily setup variation: An end‐to‐end test

The recently made available ClearView® tetrazolium salt-based gel dosimeter, encapsulated in a vial, was tested to determine feasibility in use as an end-to-end dosimeter for stereotactic radiosurgery commissioning and quality assurance. A fabricated adaptor enabled direct attachment of the gel vial lid to a rod extension. The rod was inserted into a water-filled head phantom at the open neck location and locked into position. Once quality assurance testing of the linear accelerator was completed, a stereotactic plan was deployed. Optical scanning software enabled a direct comparison of the measured positional isocenter and dose distribution to the intended plan. Delivery accuracy was verified as line-dose profile plots of measured data coincide with the planned dose location and distribution. It has been demonstrated here that ClearView® gel contained in a vial is a suitable dosimeter for verifying stereotactic radiation therapy delivery accuracy. The end-to-end testing provided is geared to work identically for any small field study, including stereotactic radiosurgery and radiotherapy, volumetric modulated arc therapy, intensity modulated radiation therapy, and three-dimensional conformal radiation therapy.

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Stereotactic radiosurgery with MLC ‐defined arcs: Verification of dosimetry, spatial accuracy, and end‐to‐end tests

Journal of Applied Clinical Medical Physics ◽

10.1002/acm2.12583 ◽

2019 ◽

Vol 20 (5) ◽

pp. 84-98 ◽

Cited By ~ 5

Author(s):

Ivan A. Brezovich ◽

Xingen Wu ◽

Richard A. Popple ◽

Elizabeth Covington ◽

Rex Cardan ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Spatial Accuracy ◽

End To End

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Robustness of single-isocenter multiple-metastasis stereotactic radiosurgery end-to-end testing across institutions

10.21203/rs.3.rs-15983/v1 ◽

2020 ◽

Author(s):

Daniel L Saenz ◽

Niko Papanikolaou ◽

Emmanouil Zoros ◽

Evangelos Pappas ◽

Michael Reiner ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Treatment Plan ◽

High Definition ◽

Data Set ◽

Passing Rate ◽

Gamma Analysis ◽

Delivery Technique ◽

End To End ◽

Single Isocenter ◽

Gamma Passing Rate

Abstract Background The accuracy of stereotactic radiosurgery to multiple brain metastases with a single isocenter using high definition dynamic radiosurgery (HDRS) was evaluated to assess robustness, repeatability, and possibility of inter-institutional quality assurance amongst multiple institutions. Methods A CT simulation scan obtained from a previously treated patient was used as the data set for targeting seven brain lesions. A VMAT treatment plan was generated using Monaco and was replicated at six HDRS-capable institutions using a plan template. All institutions subsequently irradiated 3D-printed head anthropomorphic phantoms mimicking the patient’s anatomy. Three different phantoms with a point dosimeter insert, film insert, and a gel dosimeter were used. Absolute dosimetry end-to-end dosimetric accuracy as well as gamma analysis for relative dose distribution agreement analysis was used to evaluate measurement agreement with calculation. Results Point measurements averaged across all institutions using six-degree-of-freedom treatment positioning correction were within 1.2±0.5%. The average gamma passing rate in the film plane using 3D global 3D gamma analysis was 96.6±2.2% (3%/2 mm). For all targets within 4 cm of the isocenter, the 3D dosimetric gel gamma passing rate averaged across institutions was >90% (3%/2 mm). 88.0% average gamma passing rate was found for targets beyond 4 cm. The targeting accuracy of high definition dynamic radiosurgery assessed by geometrical offset of the center of dose distributions was established across multiple institutions in this study to be within 1 mm for targets within 4 cm of isocenter. Conclusions Across variations in clinical practice, comparable dosimetry and localization is possible with this treatment planning and delivery technique.

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