Evaluation of field in field (FIF), volumetric modulated ARC therapy (VMAT) and intensity modulated radiotherapy (IMRT) methods in left breast cancer patients received radiotherapy after mastectomy

Field in Field (FIF), Intensity Modulated Radiotherapy (IMRT) and Volumetric Adjusted Ark Therapy (VMAT) technique were administered to 20 patients with left breast malignant tumors who had underwent mastectomy. Doses of breast tissue and organs at risk are aimed to be evaluated by using dose volume histograms (DVH). In the study, computerized tomography images of 20 patients were contoured by a single radiation oncolog. For each patient, 6 MV energy was used in the treatment plan with 3 different techniques. The dose distribution was 50 Gy /25 Fr. The displayed tissue after mastectomy, CTV, heart, ipslateral lung, contralateral lung and contralateral breast are contoured. The plans were prepared by using Eclipse 13.7 which is a radiotherapy network system connected to Varian device in Kütahya Evliya Çelebi Training and Researkh Hospital Radiation Oncology Clinic. In the field (FIF) method, additional fields were added with the aim of reducing the high dose areas by using the homoconcentric and beam angles. In the intensity-adjusted radiotherapy planning technique (IMRT), the homoconcentric point was prepared by sticking to the plan for FIF method within the first-last open field. In the volumetric adjusted ark therapy (VMAT) half ark technique was applied. For PTV Dort, Dmax, Dmean, CI values and for critical organs (heart, ipsilateral-lungs and counter mammary) Dort, Dmax, (%) (V5, V10, V20, V25 ve V30) were investigated. According to researkh findings, PTV Dmax value was found highest in IMRT (56,65) (p = 0.042). Dmax for the heart was detected at the lowest in IMRT (p = 0.001). Lung Dmax was found at the lowest in IMRT (45,48) (p <0.001). The lowest Dmax for the left lung was detected in IMRT (45.52) (p <0.001). No statistically significant difference was found between supra, axilla, right lung and counter mammary doses. In the lung V5 was found to be lowest in VMAT and V20, V25, V30 were found to be significantly lower in IMRT (p <0,01). V20, V25 and V30 for the heart were statistically significant at the lowest in IMRT (p <0.001). As a result of this researkh, statistically significant findings obtained from the plan of 20 patients after mastectomy with left breast cancer suggested that the IMRT technique has more positive effects on the desired dose distribution in the target tissue and the lung and heart critical organs in terms of protecting from high dose radiotherapy. Keywords: Breast Cancer, FIF, IMRT, VMAT