Sohaila Yazdani - MSc Student of medical physics, Students Research Committee, Kermanshah University of Medical Sciences, Kermanshah,Iran.
Mehran Yarahmadi - Department of Medical Physics, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran
Bahar Faramarzi - MSc Student of medical physics, Students Research Committee, Kermanshah University of Medical Sciences, Kermanshah,Iran.

Introduction & Aim: Breast cancer is the most common cancer in females around the world. Radiotherapy of breast plays an important role in the management of breast cancer. Create a uniform dose distribution in the total target volume while minimizing dose of organs at risk (OARs) are an important objective of radiation therapy, but achieving suitable dose homogeneity across the whole breast volume is difficult because of the continuous alteration in breast form across multiple planes and effect of the low-density lung tissues included in the irradiated volume. In breast cancer radiotherapy, heart and lung are main OARs. Pulmonary complications caused by radiation can go to pneumonitis and pulmonary fibrosis sometimes, at the heart of each of the pericardium, myocardium and coronary vessels can be affected by radiation. Therefore, the aim of this study is evaluation of dose received by heart and lung in radiotherapy of left breast cancer for patients who have undergone lumpectomy and treated with conventional tangential wedge fields (TW). Methods: Twenty-four female patients with left breast cancer were selected for this study. The TW planning technique was provided by the Isogray treatment planning system and dose-volume histogram (DVH) extracted for heart and Left lung. Results: DMean,Dmax,V5,V30 were for heart 3.89±2.6,47.25,12.4,7.2 respectively. For lung DMean, Dmax,V25,V30 were 11.44±4.3,51.32,23.8,22.3. Conclusion: According to the results of dose Received by heart and lung, there is no significant risk to patients.