Skip to main content

Re-examining TG-142 recommendations in light of modern techniques for linear accelerator based radiosurgery.

Publication ,  Journal Article
Faught, AM; Trager, M; Yin, F-F; Kirkpatrick, J; Adamson, J
Published in: Med Phys
October 2016

PURPOSE: The recent development of multifocal stereotactic radiosurgery (SRS) using a single isocenter volumetric modulated arc theory (VMAT) technique warrants a re-examination of the quality assurance (QA) tolerances for routine mechanical QA recommended by the American Association of Physicists in Medicine Task Group Report Number 142. Multifocal SRS can result in targets with small volumes being at a large off-axis distance from the treatment isocenter. Consequently, angular errors in the collimator, patient support assembly (PSA), or gantry could have an increased impact on target coverage. METHODS: The authors performed a retrospective analysis of dose deviations caused by systematic errors in PSA, collimator, and gantry angle at the tolerance level for routine linear accelerator QA as recommended by TG-142. Dosimetric deviations from multifocal SRS plans (N = 10) were compared to traditional single target SRS using dynamic conformal arcs (N = 10). The chief dosimetric quantities used in determining clinical impact were V100% and D99% of the individual planning target volumes and V12Gy of the healthy brain. RESULTS: Induced errors at tolerance levels showed the greatest change in multifocal SRS target coverage for collimator rotations (±1.0°) with the average changes to V100% and D99% being 5% and 6%, respectively, with maximum changes of 33% and 20%. A reduction in the induced error to half the TG-142 tolerance (±0.5°) demonstrated similar changes in coverage loss to traditional single target SRS assessed at the recommended tolerance level. The observed change in coverage for multifocal SRS was reduced for gantry errors (±1.0°) at 2% and 4.5% for V100% and D99%, respectively, with maximum changes of 18% and 12%. Minimal change in coverage was noted for errors in PSA rotation. CONCLUSIONS: This study indicates that institutions utilizing a single isocenter VMAT technique for multifocal disease should pay careful attention to the angular mechanical tolerances in designing a robust and complete QA program.

Duke Scholars

Altmetric Attention Stats
Dimensions Citation Stats

Published In

Med Phys

DOI

EISSN

2473-4209

Publication Date

October 2016

Volume

43

Issue

10

Start / End Page

5437

Location

United States

Related Subject Headings

  • Societies, Medical
  • Retrospective Studies
  • Radiotherapy, Intensity-Modulated
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy Dosage
  • Radiosurgery
  • Quality Assurance, Health Care
  • Particle Accelerators
  • Nuclear Medicine & Medical Imaging
  • Humans
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Faught, A. M., Trager, M., Yin, F.-F., Kirkpatrick, J., & Adamson, J. (2016). Re-examining TG-142 recommendations in light of modern techniques for linear accelerator based radiosurgery. Med Phys, 43(10), 5437. https://doi.org/10.1118/1.4962471
Faught, Austin M., Michael Trager, Fang-Fang Yin, John Kirkpatrick, and Justus Adamson. “Re-examining TG-142 recommendations in light of modern techniques for linear accelerator based radiosurgery.Med Phys 43, no. 10 (October 2016): 5437. https://doi.org/10.1118/1.4962471.
Faught AM, Trager M, Yin F-F, Kirkpatrick J, Adamson J. Re-examining TG-142 recommendations in light of modern techniques for linear accelerator based radiosurgery. Med Phys. 2016 Oct;43(10):5437.
Faught, Austin M., et al. “Re-examining TG-142 recommendations in light of modern techniques for linear accelerator based radiosurgery.Med Phys, vol. 43, no. 10, Oct. 2016, p. 5437. Pubmed, doi:10.1118/1.4962471.
Faught AM, Trager M, Yin F-F, Kirkpatrick J, Adamson J. Re-examining TG-142 recommendations in light of modern techniques for linear accelerator based radiosurgery. Med Phys. 2016 Oct;43(10):5437.

Published In

Med Phys

DOI

EISSN

2473-4209

Publication Date

October 2016

Volume

43

Issue

10

Start / End Page

5437

Location

United States

Related Subject Headings

  • Societies, Medical
  • Retrospective Studies
  • Radiotherapy, Intensity-Modulated
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy Dosage
  • Radiosurgery
  • Quality Assurance, Health Care
  • Particle Accelerators
  • Nuclear Medicine & Medical Imaging
  • Humans