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Dosimetric Analysis of Microscopic Disease in SBRT for Lung Cancers.

Publication ,  Journal Article
Mao, R; Tian, L; Zhang, Y; Ren, L; Gao, R; Yin, F-F; Ge, H
Published in: Technol Cancer Res Treat
December 2017

OBJECTIVE: The objective of this study is to theoretically and experimentally evaluate the dosimetry in the microscopic disease regions surrounding the tumor under stereotactic body radiation therapy of lung cancer. METHODS: For simplicity, the tumor was considered moving along 1 dimension with a periodic function. The probability distribution function of the tumor position was generated according to the motion pattern and was used to estimate the delivered dose in the microscopic disease region. An experimental measurement was conducted to validate both the estimated dose with a probability function and the calculated dose from 4-dimensional computed tomography data using a dynamic thorax phantom. Four tumor motion patterns were simulated with cos4(x) and sin(x), each with 2 different amplitudes: 10 mm and 5 mm. A 7-field conformal plan was created for treatment delivery. Both films (EBT2) and optically stimulated luminescence detectors were inserted in and around the target of the phantom to measure the delivered doses. Dose differences were evaluated using gamma analysis with 3%/3 mm. RESULTS: The average gamma index between measured doses using film and calculated doses using average intensity projection simulation computed tomography was 80.8% ± 0.9%. In contrast, between measured doses using film and calculated doses accumulated from 10 sets of 4-dimensional computed tomography data, it was 98.7% ± 0.6%. The measured doses using optically stimulated luminescence detectors matched very well (within 5% of the measurement uncertainty) with the theoretically calculated doses using probability distribution function at the corresponding position. Respiratory movement caused inadvertent irradiation exposure, with 70% to 80% of the dose line wrapped around the 10 mm region outside the target. CONCLUSION: The use of static dose calculation in the treatment planning system could substantially underestimate the actual delivered dose in the microscopic disease region for a moving target. The margin for microscopic disease may be substantially reduced or even eliminated for lung stereotactic body radiation therapy.

Duke Scholars

Published In

Technol Cancer Res Treat

DOI

EISSN

1533-0338

Publication Date

December 2017

Volume

16

Issue

6

Start / End Page

1113 / 1119

Location

United States

Related Subject Headings

  • Respiration
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy Dosage
  • Radiosurgery
  • Phantoms, Imaging
  • Oncology & Carcinogenesis
  • Movement
  • Lung Neoplasms
  • Lung
  • Humans
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Mao, R., Tian, L., Zhang, Y., Ren, L., Gao, R., Yin, F.-F., & Ge, H. (2017). Dosimetric Analysis of Microscopic Disease in SBRT for Lung Cancers. Technol Cancer Res Treat, 16(6), 1113–1119. https://doi.org/10.1177/1533034617734689
Mao, Ronghu, Lingling Tian, You Zhang, Lei Ren, Renqi Gao, Fang-Fang Yin, and Hong Ge. “Dosimetric Analysis of Microscopic Disease in SBRT for Lung Cancers.Technol Cancer Res Treat 16, no. 6 (December 2017): 1113–19. https://doi.org/10.1177/1533034617734689.
Mao R, Tian L, Zhang Y, Ren L, Gao R, Yin F-F, et al. Dosimetric Analysis of Microscopic Disease in SBRT for Lung Cancers. Technol Cancer Res Treat. 2017 Dec;16(6):1113–9.
Mao, Ronghu, et al. “Dosimetric Analysis of Microscopic Disease in SBRT for Lung Cancers.Technol Cancer Res Treat, vol. 16, no. 6, Dec. 2017, pp. 1113–19. Pubmed, doi:10.1177/1533034617734689.
Mao R, Tian L, Zhang Y, Ren L, Gao R, Yin F-F, Ge H. Dosimetric Analysis of Microscopic Disease in SBRT for Lung Cancers. Technol Cancer Res Treat. 2017 Dec;16(6):1113–1119.
Journal cover image

Published In

Technol Cancer Res Treat

DOI

EISSN

1533-0338

Publication Date

December 2017

Volume

16

Issue

6

Start / End Page

1113 / 1119

Location

United States

Related Subject Headings

  • Respiration
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy Dosage
  • Radiosurgery
  • Phantoms, Imaging
  • Oncology & Carcinogenesis
  • Movement
  • Lung Neoplasms
  • Lung
  • Humans