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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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Related in: MedlinePlus

The GV (red) position versus RV (green) contour of electron boost in the EBEV relative to the cut-out (blue). Magenta is the digitized scar.
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Figure 5: The GV (red) position versus RV (green) contour of electron boost in the EBEV relative to the cut-out (blue). Magenta is the digitized scar.

Mentions: For electron boosts, patient were aligned according to the instructions of the plan set up maintaining the couch and gantry at zero degrees. The 3D-US image was acquired. The seroma cavity as seen on this image was contoured using semi-automatic tools on the US-Guide to define the GV. The Clarity digitizer, a ball-point tip tool with infrared markers, was used to digitize the scar. This provided both internal and external anatomy in the electron beam's eye view (EBEV). The Clarity couch positioning indicator (CPI) was then affixed to the treatment couch, and the couch was moved and rotated into final treatment position. The CPI tracked these couch motions, and gantry angle changes were typed in manually. As shown in Figure 5, the Clarity screen showed the alignment of the GV and scar relative to the cut-out in real-time as the patient was brought into treatment position, as well as the overlay of the RV reference contour for comparison.


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)

The GV (red) position versus RV (green) contour of electron boost in the EBEV relative to the cut-out (blue). Magenta is the digitized scar.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: The GV (red) position versus RV (green) contour of electron boost in the EBEV relative to the cut-out (blue). Magenta is the digitized scar.
Mentions: For electron boosts, patient were aligned according to the instructions of the plan set up maintaining the couch and gantry at zero degrees. The 3D-US image was acquired. The seroma cavity as seen on this image was contoured using semi-automatic tools on the US-Guide to define the GV. The Clarity digitizer, a ball-point tip tool with infrared markers, was used to digitize the scar. This provided both internal and external anatomy in the electron beam's eye view (EBEV). The Clarity couch positioning indicator (CPI) was then affixed to the treatment couch, and the couch was moved and rotated into final treatment position. The CPI tracked these couch motions, and gantry angle changes were typed in manually. As shown in Figure 5, the Clarity screen showed the alignment of the GV and scar relative to the cut-out in real-time as the patient was brought into treatment position, as well as the overlay of the RV reference contour for comparison.

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