Abstract :
Breast cancer is the most prevalent cancer in women worldwide. The aim of this study is to compare dosimetric parameters obtained by different physicists and planning techniques in treatment planning and dose delivery for 3D-conformal radiotherapy using wedged and field in field (FIF) techniques for breast cancer. Radiotherapy treatment data of 15 patients with left breast cancer in stage II were evaluated for wedged and FIF techniques. These plans were compared based on evaluating the accuracy of physicists in treatment design in the term of the dose to planning-target-volume (PTV) and organ-at-risk (OAR). The results demonstrated a statistical difference between treatment planning of two physicists. FIF establishes better dosimetric parameters including Dmax and V95 Gy for PTV, Dmean, V20 Gy, and V30 Gy in lungs, Dmean, V5 Gy, V20 Gy, and V25 Gy in heart, and Dmean and D2 in LAD. Designed plans by first physicist showed higher uniformity in dose distribution in PTV and lower dose to OARs which will lead to reducing radiobiological complications. According to both physicist results, FIF significantly reduces hot spots and obtains better dose distribution in PTV. Furthermore, by FIF, the received dose to the left lung is considerably decreased which is accompanied by a risk reduction for pulmonary complications. Physicist's ability affects the accuracy of achieving dose conformity for PTV and protection for OARs. FIF technique establishes better curative efficiency and better coverage in PTV as well as higher protection of OARs.
