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Image guidance using 3D-ultrasound (3D-US) for daily positioning of lumpectomy cavity for boost irradiation.

Chadha M, Young A, Geraghty C, Masino R, Harrison L - Radiat Oncol (2011)

Bottom Line: For electron boosts, shifts were 1.0 ± 0.5 cm and 52% fell outside the dosimetric penumbra.Interfraction analysis relative to the first fraction noted the shifts to be 0.8 ± 0.4 cm and 36% fell outside the penumbra.Further studies to better define the protocol for clinical application of IGRT in breast cancer is needed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Radiation Oncology, Beth Israel Medical Center, New York, NY, USA. mchadha@chpnet.org

ABSTRACT

Purpose: The goal of this study was to evaluate the use of 3D ultrasound (3DUS) breast IGRT for electron and photon lumpectomy site boost treatments.

Materials and methods: 20 patients with a prescribed photon or electron boost were enrolled in this study. 3DUS images were acquired both at time of simulation, to form a coregistered CT/3DUS dataset, and at the time of daily treatment delivery. Intrafractional motion between treatment and simulation 3DUS datasets were calculated to determine IGRT shifts. Photon shifts were evaluated isocentrically, while electron shifts were evaluated in the beam's-eye-view. Volume differences between simulation and first boost fraction were calculated. Further, to control for the effect of change in seroma/cavity volume due to time lapse between the 2 sets of images, interfraction IGRT shifts using the first boost fraction as reference for all subsequent treatment fractions were also calculated.

Results: For photon boosts, IGRT shifts were 1.1 ± 0.5 cm and 50% of fractions required a shift >1.0 cm. Volume change between simulation and boost was 49 ± 31%. Shifts when using the first boost fraction as reference were 0.8 ± 0.4 cm and 24% required a shift >1.0 cm. For electron boosts, shifts were 1.0 ± 0.5 cm and 52% fell outside the dosimetric penumbra. Interfraction analysis relative to the first fraction noted the shifts to be 0.8 ± 0.4 cm and 36% fell outside the penumbra.

Conclusion: The lumpectomy cavity can shift significantly during fractionated radiation therapy. 3DUS can be used to image the cavity and correct for interfractional motion. Further studies to better define the protocol for clinical application of IGRT in breast cancer is needed.

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Distribution of cavity shifts for photon boost in (a) Ant/Post, (b) Sup/Inf, (c) Right/Left and (d) radial directions, using GV from the first RT fraction US.
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Figure 10: Distribution of cavity shifts for photon boost in (a) Ant/Post, (b) Sup/Inf, (c) Right/Left and (d) radial directions, using GV from the first RT fraction US.

Mentions: Histograms of the IGRT shift (center of the GV to center of RV) are shown in Figure 9. The average radial shift was 1.1 ± 0.5 cm. Table 1. However, because we had also observed change in cavity volume between simulation and the first boost fraction, the magnitude of the shift could not entirely be attributed to variation in set up and motion of cavity during daily therapy. In order to exclude the effect of change in seroma volume used for image guidance during the boost phase, we evaluated the shifts of the GV between the first boost fraction and GV for the subsequent boost fractions. Histograms for these shifts excluding the RV are shown in Figure 10. The average radial shift was 0.8 ± 0.4 cm. Table 2.


Image guidance using 3D-ultrasound (3D-US) for daily positioning of lumpectomy cavity for boost irradiation.

Chadha M, Young A, Geraghty C, Masino R, Harrison L - Radiat Oncol (2011)

Distribution of cavity shifts for photon boost in (a) Ant/Post, (b) Sup/Inf, (c) Right/Left and (d) radial directions, using GV from the first RT fraction US.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3113959&req=5

Figure 10: Distribution of cavity shifts for photon boost in (a) Ant/Post, (b) Sup/Inf, (c) Right/Left and (d) radial directions, using GV from the first RT fraction US.
Mentions: Histograms of the IGRT shift (center of the GV to center of RV) are shown in Figure 9. The average radial shift was 1.1 ± 0.5 cm. Table 1. However, because we had also observed change in cavity volume between simulation and the first boost fraction, the magnitude of the shift could not entirely be attributed to variation in set up and motion of cavity during daily therapy. In order to exclude the effect of change in seroma volume used for image guidance during the boost phase, we evaluated the shifts of the GV between the first boost fraction and GV for the subsequent boost fractions. Histograms for these shifts excluding the RV are shown in Figure 10. The average radial shift was 0.8 ± 0.4 cm. Table 2.

Bottom Line: For electron boosts, shifts were 1.0 ± 0.5 cm and 52% fell outside the dosimetric penumbra.Interfraction analysis relative to the first fraction noted the shifts to be 0.8 ± 0.4 cm and 36% fell outside the penumbra.Further studies to better define the protocol for clinical application of IGRT in breast cancer is needed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Radiation Oncology, Beth Israel Medical Center, New York, NY, USA. mchadha@chpnet.org

ABSTRACT

Purpose: The goal of this study was to evaluate the use of 3D ultrasound (3DUS) breast IGRT for electron and photon lumpectomy site boost treatments.

Materials and methods: 20 patients with a prescribed photon or electron boost were enrolled in this study. 3DUS images were acquired both at time of simulation, to form a coregistered CT/3DUS dataset, and at the time of daily treatment delivery. Intrafractional motion between treatment and simulation 3DUS datasets were calculated to determine IGRT shifts. Photon shifts were evaluated isocentrically, while electron shifts were evaluated in the beam's-eye-view. Volume differences between simulation and first boost fraction were calculated. Further, to control for the effect of change in seroma/cavity volume due to time lapse between the 2 sets of images, interfraction IGRT shifts using the first boost fraction as reference for all subsequent treatment fractions were also calculated.

Results: For photon boosts, IGRT shifts were 1.1 ± 0.5 cm and 50% of fractions required a shift >1.0 cm. Volume change between simulation and boost was 49 ± 31%. Shifts when using the first boost fraction as reference were 0.8 ± 0.4 cm and 24% required a shift >1.0 cm. For electron boosts, shifts were 1.0 ± 0.5 cm and 52% fell outside the dosimetric penumbra. Interfraction analysis relative to the first fraction noted the shifts to be 0.8 ± 0.4 cm and 36% fell outside the penumbra.

Conclusion: The lumpectomy cavity can shift significantly during fractionated radiation therapy. 3DUS can be used to image the cavity and correct for interfractional motion. Further studies to better define the protocol for clinical application of IGRT in breast cancer is needed.

Show MeSH
Related in: MedlinePlus