Abstract 390P
Background
Aim: This study aimed to evaluate the effects of VMAT and IMRT treatment techniques on critical organs and the target tumor in lung cancer patients using treatment planning systems with different treatment planning algorithms.
Methods
This study includes 21 cancer patients who received radiotherapy for inoperable and unresectable T2-T4 N0-N1 M0 NSCLC in our clinic. After delinition of the target volume and critical organs, two different treatment techniques of Intensity-Modulated Radiotherapy (IMRT),specifically ‘Step and Shoot’ IMRT and Volumetric Modulated Arc Therapy (VMAT), were utilized to compare the effects of different algorithms.Monte Carlo (MC),Pencil Beam algorithm(PB),Anisotropic Analytical Algorithm(AAA),Acuros XB(AXB)algorithms and Convolution Superposition algorithm (C/S) were used in the treatment plans of the patients.The prescribed dose to the PTV was 60Gy in 30 fractions. The statistical analysis was conducted using SPSS statistical software version 29.0.2.0.The Friedman test was used to compare independent groups (p < 0.05).If the Friedman test revealed statistical significance, the results were evaluated using the Bonferroni-corrected Wilcoxon rank test (p < 0.005 for VMAT, p < 0.008 for IMRT).
Results
The C/S algorithm yielded similar results close to those of MC. In the analysis of plans using the IMRT technique, statistically significant differences were noted among algorithms in the Dmean, D2, and D5 values for the target volume. There were notably marked differences in the low-dose volume regions of the total lung, contralateral lung, and ipsilateral lung slice-based dose distribitions and DVHs.
Conclusions
In this study, when comparing the target volume values, it was found that the PB algorithm hasn’t taken into account for certain physical parameters, resulting in overly optimistic PTV coverage and lower critical organ doses for both VMAT and IMRT techniques. For both treatment techniques, the AAA and AXB algorithms showed similar dose values and dose distributions for both the PTV and critical organs. Among the algorithms evaluated, these two algorithms of AAA and AXB displayed higher maximum dose values within the tumor volume.
Funding
Has not received any funding
Disclosure
The author has declared no conflicts of interest.