The effect of different calculation algorithms in non-small-cell lung cancer 3-dimensional conformal radiotherapy planning on lung dose-volume parameters

OBJECTIVES: It was aimed to compare two different planning algorithms (Pencil Beam and Convolution Superposition) with regard to lung dose-volume parameters obtained from the created 3-D conformal radiotherapy plans of lung cancer patients who had lobectomy/bilobectomy surgery. METHODS: The treatment plans of 10 lung cancer patients administered adjuvant 3-D conformal radiotherapy were evaluated in this study. Using two different algorithms, calculations were performed for 6 and 18 MV-X photon beams, respectively. The differences on the relevant lung dose-volume parameters were analyzed. RESULTS: In terms of lung dose-volume parameters, the difference between the algorithms was statistically significant in V5, V13 and V30 obtained from plans for 6 MV-X photon beam energy (p=0.005; p=0.005; p=0.008, respectively). CONCLUSION: Higher values were found especially in parameters expressing “low dose area of lungs” for Convolution/Superposition algorithm in radiotherapy planning. Convolution/Superposition algorithm should be preferred to Pencil Beam algorithm due to its increased accuracy in dose calculation in radiotherapy planning.