An improved internal mammary irradiation technique in radiation treatment of locally advanced breast cancers.
ABSTRACT The purpose of the present study was to compare a new internal mammary irradiation technique with traditional techniques for locally advanced breast cancers in terms of sparing ipsilateral lung and heart and reducing the "cold" and "hot spots"in breast tissue. The new technique uses wide tangential fields for the first eight fractions of treatment. A medial internal mammary field (IMF) of electrons matched with narrowed tangential fields is used for the remaining fractions. Intensity-modulated radiation therapy (IMRT) by means of segmented multileaf collimation (SMLC) is used in the narrowed tangential fields to improve the match between the electron and the photon fields. Treatment planning was performed to compare this technique to a wide-tangential-only technique and to a traditional oblique IMF technique for three patients with differing habitus. Film dosimetry was performed in a solid water phantom to confirm the planning results. For all three patients, the mean doses of the ipsilateral lung and the heart were significantly reduced with the new technique. The lung and the heart volumes were remarkably reduced at lowdose levels (< or =12 Gy) compared to the traditional IMF technique, and significantly reduced at all dose levels compared to the wide tangential technique. The new technique also reduced the "cold" and "hot spots" along the match plane between the IMF and the tangential fields compared to the traditional IMF technique. In conclusion, the new IMF technique shows dosimetric improvement compared to the traditional IMF technique in terms of the critical organ sparing and target dose uniformity.
- Oncologie 01/2006; 8(3):282-284. · 0.10 Impact Factor
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ABSTRACT: Imaging and local therapy are important modalities for detection and management of localized breast cancer. Improvements in screening and local therapy have contributed to reduced breast cancer-associated morbidity and mortality. The Coalition of Cancer Cooperative Groups (CCCG) convened the Scientific Leadership Council (SLC) in breast cancer, an expert panel, to identify priorities for future research and current trials with greatest practice-changing potential. Panelists formed a consensus on research priorities for breast imaging and locoregional therapy, and also identified six trials judged to be of high priority. Current high priority trials included trials determining: (1) the role of accelerated partial breast versus whole-breast radiation (B39), (2) the feasibility, safety, and local and systemic control of small localized breast cancers treated with tumor ablation (Z1072), (3) the role of removal of the primary cancer in selected patients with metastatic disease (E2108), and (4) the clinical and biological effects of pre-operative anti-HER2-directed and ER-directed therapies in localized or locally advanced breast cancer (B41, Z1031, Z1041). Ongoing and future trials will further refine optimal locoregional management, and additional research is required to develop improved screening methods and identify high risk populations most likely to benefit from targeted screening.Breast Cancer Research and Treatment 12/2009; 120(2):273-84. · 4.47 Impact Factor
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ABSTRACT: Electron beam radiotherapy is an accepted method to treat shallow tumors. However, modulation of electrons to customize dose distributions has not readily been achieved. Studies of bolus and tertiary collimation systems have been met with limitations. We pursue the use of photon multi-leaf collimators (MLC) for modulated electron radiotherapy (MERT) to achieve customized distributions for potential clinical use. As commercial planning systems do not support the use of MLC with electrons, planning was conducted using Monte Carlo calculations. Segmented and dynamic modulated delivery of multiple electron segments was configured, calculated and delivered for validation. Delivery of electrons with segmented or dynamic leaf motion was conducted. A phantom possessing an idealized stepped target was planned and optimized with subsequent validation by measurements. Finally, clinical treatment plans were conducted for post-mastectomy and cutaneous lymphoma of the scalp using forward optimization techniques. Comparison of calculations and measurements was successful with agreement of +/-2%/2 mm for the energies, segment sizes, depths tested for delivered segments for the dynamic and segmented delivery. Clinical treatment plans performed provided optimal dose coverage of the target while sparing distal organs at risk. Execution of plans using an anthropomorphic phantom to ensure safe and efficient delivery was conducted. Our study validates that MERT is not only possible using the photon MLC, but the efficient and safe delivery inherent with the dynamic delivery provides an ideal technique for shallow tumor treatment.Physics in Medicine and Biology 02/2009; 54(2):327-39. · 2.70 Impact Factor