New method for estimation of fluence complexity in IMRT fields and correlation with gamma analysis

8th International Conference on 3D Radiation Dosimetry

Hanuová, T.^1,2 ; Vondráek, V.^3 ; Badraoui-Uprová, K.^1,3 ; Horáková, I.^4 ; Koniarová, I.^1,4

Department of Dosimetry and Application of Ionizing Radiation, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Behová 7, Praha 1

115 19, Czech Republic^1

Hospital Na Bulovce, Budinova 67/2, Praha 8

180 81, Czech Republic^2

Proton Therapy Center Czech, Budinova 2437/1a, Praha 8

180 00, Czech Republic^3

National Radiation Protection Institute, Bartokova 28, Praha 4

140 00, Czech Republic^4

关键词: Dose calculation;    Dose gradients;    Gamma analysis;    Intensity-modulated radiation therapy;    Measuring process;    Portal images;    Re-planning;    Varian medical systems;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/573/1/012056/pdf
DOI  :  10.1088/1742-6596/573/1/012056

来源: IOP

【 摘 要 】

A new method for estimation of fluence complexity in Intensity Modulated Radiation Therapy (IMRT) fields is proposed. Unlike other previously published works, it is based on portal images calculated by the Portal Dose Calculation algorithm in Eclipse (version 8.6, Varian Medical Systems) in the plane of the EPID aS500 detector (Varian Medical Systems). Fluence complexity is given by the number and the amplitudes of dose gradients in these matrices. Our method is validated using a set of clinical plans where fluence has been smoothed manually so that each plan has a different level of complexity. Fluence complexity calculated with our tool is in accordance with the different levels of smoothing as well as results of gamma analysis, when calculated and measured dose matrices are compared. Thus, it is possible to estimate plan complexity before carrying out the measurement. If appropriate thresholds are determined which would distinguish between acceptably and overly modulated plans, this might save time in the re-planning and re-measuring process.