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Effects of breathing variation on gating window internal target volume in respiratory gated radiation therapya).

Publication ,  Journal Article
Cai, J; McLawhorn, R; Read, PW; Larner, JM; Yin, F-F; Benedict, SH; Sheng, K
Published in: Med Phys
August 2010

PURPOSE: To investigate the effects of breathing variation on gating window internal target volume(ITVGW) in respiratory gated radiation therapy. METHOD AND MATERIALS: Two-dimensional dynamic MRI (dMRI) of lung motion was acquired in ten volunteers and eight lung cancer patients. Resorted dMRI using 4DCT acquisition method (RedCAM) was generated for selected subjects by simulating the image rebinning process. A dynamic software generated phantom (dSGP) was created by moving a solid circle (to mimic the "tumor") with dMRI-determined motion trajectories. The gating window internal target area (ITAGW, 2D counterpart of ITVGW) was determined from both RedCAM and dSGP/dMRI. Its area (A), major axis (L1), minor axis (L2), and similarity (S) were calculated and compared. RESULTS: In the phantom study of 3 cm tumor, measurements of theITAGW from dSGP (A=10.0±1.3cm2, L1=3.8±0.4cm, and L2=3.3±0.1cm) are significantly (p<0.001) greater than those from RedCAM (A=8.5±0.7cm2, L1=3.5±0.2cm, and L2=3.1±0.1cm). Similarly, the differences are significantly greater (p<0.001) for the 1 cm tumor (A=1.9±0.5cm2, L1=1.9±0.4cm, and L2=1.3±0.1cm in dSGP; A=1.3±0.1cm2, L1=1.5±0.2cm, and L2=1.1±0.1cm in RedCAM). In patient studies, measurements of the ITAGW from dMRI (A=15.5±8.2cm2, L1=5.0±1.1cm, and L2=3.8±1.2cm) are also significantly greater (p<0.05) than those from RedCAM (A=13.2±8.5cm2, L1=4.3±1.4cm, and L2=3.7±1.2cm). Similarities were 0.9±0.1, 0.8±0.1, and 0.8±0.1 in the 3 cm tumor phantom, 1 cm tumor phantom, and patient studies, respectively. CONCLUSION: ITVGW can be underestimated by 4DCT due to breathing variations. An additional margin may be needed to account for this potential error in generating a PTVGW. Cautions need to be taken when generating ITVGW from 4DCT in respiratory gated radiation therapy, especially for small tumors (<3cm) with a large motion range (>1cm).

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Published In

Med Phys

DOI

EISSN

2473-4209

Publication Date

August 2010

Volume

37

Issue

8

Start / End Page

3927 / 3934

Location

United States

Related Subject Headings

  • Tomography, X-Ray Computed
  • Sensitivity and Specificity
  • Respiratory-Gated Imaging Techniques
  • Respiratory Mechanics
  • Reproducibility of Results
  • Radiotherapy, Conformal
  • Radiotherapy, Computer-Assisted
  • Nuclear Medicine & Medical Imaging
  • Middle Aged
  • Male
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Cai, J., McLawhorn, R., Read, P. W., Larner, J. M., Yin, F.-F., Benedict, S. H., & Sheng, K. (2010). Effects of breathing variation on gating window internal target volume in respiratory gated radiation therapya). Med Phys, 37(8), 3927–3934. https://doi.org/10.1118/1.3457329
Cai, Jing, Robert McLawhorn, Paul W. Read, James M. Larner, Fang-Fang Yin, Stanley H. Benedict, and Ke Sheng. “Effects of breathing variation on gating window internal target volume in respiratory gated radiation therapya).Med Phys 37, no. 8 (August 2010): 3927–34. https://doi.org/10.1118/1.3457329.
Cai J, McLawhorn R, Read PW, Larner JM, Yin F-F, Benedict SH, et al. Effects of breathing variation on gating window internal target volume in respiratory gated radiation therapya). Med Phys. 2010 Aug;37(8):3927–34.
Cai, Jing, et al. “Effects of breathing variation on gating window internal target volume in respiratory gated radiation therapya).Med Phys, vol. 37, no. 8, Aug. 2010, pp. 3927–34. Pubmed, doi:10.1118/1.3457329.
Cai J, McLawhorn R, Read PW, Larner JM, Yin F-F, Benedict SH, Sheng K. Effects of breathing variation on gating window internal target volume in respiratory gated radiation therapya). Med Phys. 2010 Aug;37(8):3927–3934.

Published In

Med Phys

DOI

EISSN

2473-4209

Publication Date

August 2010

Volume

37

Issue

8

Start / End Page

3927 / 3934

Location

United States

Related Subject Headings

  • Tomography, X-Ray Computed
  • Sensitivity and Specificity
  • Respiratory-Gated Imaging Techniques
  • Respiratory Mechanics
  • Reproducibility of Results
  • Radiotherapy, Conformal
  • Radiotherapy, Computer-Assisted
  • Nuclear Medicine & Medical Imaging
  • Middle Aged
  • Male