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SU-E-T-159: Evaluation of a Patient Specific QA Tool Based On TG119.

Publication ,  Conference
Ashmeg, S; Zhang, Y; O' Daniel, J; Yin, F; Ren, L
Published in: Med Phys
June 2014

PURPOSE: To evaluate the accuracy of a 3D patient specific QA tool by analysis of the results produced from associated software in homogenous phantom and heterogonous patient CT. METHODS: IMRT and VMAT plans of five test suites introduced by TG119 were created in ECLIPSE on a solid water phantom. The ten plans -of increasing complexity- were delivered to Delta4 to give a 3D measurement. The Delta4's "Anatomy" software uses the measured dose to back-calculate the energy fluence of the delivered beams, which is used for dose calculation in a patient CT using a pencilbeam algorithm. The effect of the modulated beams' complexity on the accuracy of the "Anatomy" calculation was evaluated. Both measured and Anatomy doses were compared to ECLIPSE calculation using 3% - 3mm gamma criteria.We also tested the effect of heterogeneity by analyzing the results of "Anatomy" calculation on a Brain VMAT and a 3D conformal lung cases. RESULTS: In homogenous phantom, the gamma passing rates were found to be as low as 74.75% for a complex plan with high modulation. The mean passing rates were 91.47% ± 6.35% for "Anatomy" calculation and 99.46% ± 0.62% for Delta4 measurements.As for the heterogeneous cases, the rates were 96.54%±3.67% and 83.87%±9.42% for Brain VMAT and 3D lung respectively. This increased error in the lung case could be due to the use of the pencil beam algorithm as opposed to the AAA used by ECLIPSE.Also, gamma analysis showed high discrepancy along the beam edge in the "Anatomy" calculated results. This suggests a poor beam modeling in the penumbra region. CONCLUSION: The results show various sources of errors in "Anatomy" calculations. These include beam modeling in the penumbra region, complexity of a modulated beam (shown in homogenous phantom and brain cases) and dose calculation algorithms (3D conformal lung case).

Duke Scholars

Published In

Med Phys

DOI

ISSN

0094-2405

Publication Date

June 2014

Volume

41

Issue

6

Start / End Page

259

Location

United States

Related Subject Headings

  • Nuclear Medicine & Medical Imaging
  • 5105 Medical and biological physics
  • 4003 Biomedical engineering
  • 1112 Oncology and Carcinogenesis
  • 0903 Biomedical Engineering
  • 0299 Other Physical Sciences
 

Citation

APA
Chicago
ICMJE
MLA
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Ashmeg, S., Zhang, Y., O’ Daniel, J., Yin, F., & Ren, L. (2014). SU-E-T-159: Evaluation of a Patient Specific QA Tool Based On TG119. In Med Phys (Vol. 41, p. 259). United States. https://doi.org/10.1118/1.4888488
Ashmeg, S., Y. Zhang, J. O’ Daniel, F. Yin, and L. Ren. “SU-E-T-159: Evaluation of a Patient Specific QA Tool Based On TG119.” In Med Phys, 41:259, 2014. https://doi.org/10.1118/1.4888488.
Ashmeg S, Zhang Y, O’ Daniel J, Yin F, Ren L. SU-E-T-159: Evaluation of a Patient Specific QA Tool Based On TG119. In: Med Phys. 2014. p. 259.
Ashmeg, S., et al. “SU-E-T-159: Evaluation of a Patient Specific QA Tool Based On TG119.Med Phys, vol. 41, no. 6, 2014, p. 259. Pubmed, doi:10.1118/1.4888488.
Ashmeg S, Zhang Y, O’ Daniel J, Yin F, Ren L. SU-E-T-159: Evaluation of a Patient Specific QA Tool Based On TG119. Med Phys. 2014. p. 259.

Published In

Med Phys

DOI

ISSN

0094-2405

Publication Date

June 2014

Volume

41

Issue

6

Start / End Page

259

Location

United States

Related Subject Headings

  • Nuclear Medicine & Medical Imaging
  • 5105 Medical and biological physics
  • 4003 Biomedical engineering
  • 1112 Oncology and Carcinogenesis
  • 0903 Biomedical Engineering
  • 0299 Other Physical Sciences