MRI Guidance for Accelerated Partial Breast Irradiation in Prone Position: Imaging Protocol Design and Evaluation
- Department of Radiation Oncology, Stanford University, Stanford, CA (United States)
- Department of Radiology, Stanford University, Stanford, CA (United States)
Purpose: To design and evaluate a magnetic resonance imaging (MRI) protocol to be incorporated in the simulation process for external beam accelerated partial breast irradiation. Methods and Materials: An imaging protocol was developed based on an existing breast MRI technique with the patient in the prone position on a dedicated coil. Pulse sequences were customized to exploit T1 and T2 contrast mechanisms characteristic of lumpectomy cavities. A three-dimensional image warping algorithm was included to correct for geometric distortions related to nonlinearity of spatially encoding gradients. Respiratory motion, image distortions, and susceptibility artifacts of 3.5-mm titanium surgical clips were examined. Magnetic resonance images of volunteers were acquired repeatedly to analyze residual setup deviations resulting from breast tissue deformation. Results: The customized sequences generated high-resolution magnetic resonance images emphasizing lumpectomy cavity morphology. Respiratory motion was negligible with the subject in the prone position. The gradient-induced nonlinearity was reduced to less than 1 mm in a region 15 cm away from the isocenter of the magnet. Signal-void regions of surgical clips were 4 mm and 8 mm for spin echo and gradient echo images, respectively. Typical residual repositioning errors resulting from breast deformation were estimated to be 3 mm or less. Conclusions: MRI guidance for accelerated partial breast irradiation with the patient in the prone position with adequate contrast, spatial fidelity, and resolution is possible.
- OSTI ID:
- 21282025
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 75, Issue 1; Other Information: DOI: 10.1016/j.ijrobp.2009.03.063; PII: S0360-3016(09)00577-X; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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