21 VMAT vs. 3DCRT : quantitative dosimetric study for the lung cancer

• Published in: Physica medica 2018-12, Vol.56, p.49-50
• Main Authors: Lauzin, Y., Henni, A. Hadj, Thureau, S., Pirault, N., Dubos, B., Clarisse, P., Linca, S., Gensanne, D.
• Format: Article
• Language: English
• ISSN: 1120-1797; 1724-191X
• DOI: 10.1016/j.ejmp.2018.09.103

The dosimetric impact of VMAT in lung cancer compared with 3DCRT is well known and confirmed by several publications. The aim of this study is to quantify these results more accurately in our local clinical context, based on thirty-six patients treated with 3DCRT between 2015 and 2017. For each patient treated with 3DCRT for non-small cell pulmonary tumors with a prescription dose of 2 Gy/daily to 66 Gy, a second VMAT treatment plan was calculated with the Eclipse 13.6 treatment planning system (AAA 13.6.23, Varian®). Volumetric modulated arc therapy plans were created using either two complete arcs or two partial arcs, depending on the location of the irradiated volume. The Paddick conformity index and a homogeneity index ([D98% -D2%]/ Dmoy) were used to compare the doses delivered at the target volume (PTV). Concerning the organs at risk we compared the values of the usual dosimetric parameters used to validate a plan treatment. The volumes of the 5, 10 and 15 Gy isodose lines were compared to investigate the low doses delivered to the body by the two irradiation plans. The Paddick conformity index for the PTV is 52% greater for VMAT (0.87) than the 3DCRT (0.57) (p