The significance of 4D CT simulation in precise definition of target volume lung carcinoma intensity modulated radiation therapy treatment
Implementation of IMRT with 4DCT simulation offers possibility to correlate the respiratory movements and position of tumor volume during radiotherapy treatment. The aim of this study is to quantify movements of primary tumor during IMRT treatment in three axes-Z-superoinferiorSI, X-mediolateral ML, Y -anteroposterior AP.This study included 15 patients with lung carcinomareferred to radical radiotherapy. Contouring of GTV was done in the phases FBGTV FB, phase 0-GTV0, phase 50GTV 50, and phase MIP-GTV MIP. Comparison was done with GTV FB as basic value. Evaluation was done in three axis-SI, AP, ML. The movements of GTV in relation to X axis were in the range 0.02-0.47 cm, in relation to Y axis in the range from 0.01-0.56 cm, and according to the Z axis in the range of 0.00-0.79 cm. Based on the results of t-test there was a statistically significant difference (p<0.05) related to X axis between the upper and lower lobe. There was no statistically significant difference (p>0.05) between the upper, lower and middle lobes related to Y and Z axis. The test results which were obtained after the 4D CT simulation and planning of IMRT treatment show the importance of high-quality and precise radiation therapy treatment.