Analysis of Radiation Dose Distribution and Organs at Risk in Breast Cancer Using Intensity Modulated Radiation Therapy Technique on A Linear Accelerator at RSUP Prof. Dr. I.G.N.G. Ngoerah

Abstract

The aim of the study was to analyze the radiation dose distribution in breast cancer cases using IMRT techniques on a LINAC equipment, specifically examining the Conformity Index (CI), Homogeneity Index (HI), and radiation dose distribution to the OAR, including lungs and heart on a 6 MV photon beam energy LINAC equipment at the Radiotherapy Sub-Installation of Prof. Dr. I.G.N.G Ngoerah Hospital. Analysis of the Conformity Index (CI), Homogeneity Index (HI) and radiation dose distribution to the OAR, namely the lungs and heart in cases of right and left breast cancer using statistical data on the Dose Volume Histogram (DHV) graphic obtained from patient calculations using the Treatment Planning System (TPS) Monaco. The CI value for the right and left breast cancer cases is 0.9819 and 0.9942 respectively with a nonparametric statistical test result of 0.141 that greater than 0.05 which means it is not significant. Meanwhile, the HI values for the right and left breast cancer cases are 0.1211 and 0.1410 respectively with the multivariate statistical test result of 0.159 that greater than 0.05 which means it is not significant. For the dose distribution values in the lungs close and far from the cancer, the average values of 32.24% and 440.03 cGy for right breast cancer and 33.04% and 500.55 cGy for left breast cancer were obtained, respectively, with a multivariate statistical test value for both of them of 0.115 that greater than 0.05 in the lungs close to the cancer and 0.124≥0.05 in the lungs far from the cancer, which means insignificant. As for the heart, a value of 3.13% was obtained for right breast cancer and 8.02% for left breast cancer with a nonparametric statistical test result of 0.000 that less than 0.05 which means significant. This can be caused by the position of the heart in cases of left breast cancer closer to the target or cancer than cases of left breast cancer.