Investigation of the effect of patient respiratory movement on dose distribution in lung cancer radiotherapy for different planning techniques

Lung cancer is the type of cancer that causes the most deaths in the world.Although the first and definitive treatment method of diagnosed patients is surgery,it cannot be applied due to factors such as physical condition of the patients.Radiotherapy is a treatment method often used in combination with chemotherapy in inoperable patients. Organ mobility,which is one of the most important problems encountered in radiotherapy,causes the target not to be irradiated as planned,tissues to be exposed to high doses and treatment not to be applied correctly.Active respiratory control application reduces the movement caused by respiration,minimizes the displacement of tumor,and can provide treatments with more precision and accuracy. In our study,the effect of respiratory movements on dose distribution in active respiratory controlled radiotherapy performed with 2-phases of lung cancer with free breathing and deep inspiration,treatment plans were created with 3-dimensional conformal(3D-CRT) and volumetric arc(VMAT) treatment techniques,and dose distribution of target volume,it was aimed to compare the advantages of critical organ doses and treatment techniques against each other. At the end of our study,regardless of the radiotherapy technique used in lung irradiation, it was observed that the critical organ doses were reduced by the deep inspiration method.Deep inspiration breathing method can be seen as a reliable technique in the treatment of patients with thoracic lung cancer who can cooperate with respiratory control systems.VMAT treatment technique is a preferred radiotherapy technique in lung cancer irradiation because it provides high dose conformity-homogeneity compared to 3D-CRT technique and is more successful in reducing critical organ doses.