TY - JOUR
T1 - A sliding-window approach for improved VMAT dose calculation accuracy
AU - Alahmad, Haitham N.
AU - Park, Ji Yeon
AU - Potter, Nicholas J.
AU - Lu, Bo
AU - Yan, Guanghua
AU - Liu, Chihray
AU - Li, Jonathan G.
N1 - Publisher Copyright:
© Published under licence by IOP Publishing Ltd.
PY - 2019/8/29
Y1 - 2019/8/29
N2 - A sliding-window (SW) methodology for VMAT dose calculation was developed. For any two adjacent VMAT control points (CPs) n and n+1, the dose distribution was approximated by a 2-CP SW IMRT beam with the starting MLC positions at CP n and ending MLC positions at CP n+1, with the gantry angle fixed in the middle of the two VMAT CPs. Therefore, for any VMAT beam with N CPs, the dose is calculated with N-1 SW beams. VMAT plans were generated for ten patients in Pinnacle using 4- gantry spacing. For each patient, the VMAT plan was converted to a SW IMRT plan and dose was re-calculated. Another VMAT plan, with 1- gantry spacing, was created by interpolating the original VMAT beam. The original plans were delivered on an Elekta Versa HD and measured with Mapcheck2 using an in-house developed subarc method. For both the isodose distribution and DVH, there were significant differences between the original VMAT plan and either the SW or the interpolated plan. However, they were indistinguishable between the SW and interpolated plans. The average passing rate between the original VMAT plan and measurements was 84%. For both the interpolated and SW plans, the average passing rate was 96%. We conclude that the proposed SW approach improves VMAT dose calculation accuracy without increase in dose calculation time.
AB - A sliding-window (SW) methodology for VMAT dose calculation was developed. For any two adjacent VMAT control points (CPs) n and n+1, the dose distribution was approximated by a 2-CP SW IMRT beam with the starting MLC positions at CP n and ending MLC positions at CP n+1, with the gantry angle fixed in the middle of the two VMAT CPs. Therefore, for any VMAT beam with N CPs, the dose is calculated with N-1 SW beams. VMAT plans were generated for ten patients in Pinnacle using 4- gantry spacing. For each patient, the VMAT plan was converted to a SW IMRT plan and dose was re-calculated. Another VMAT plan, with 1- gantry spacing, was created by interpolating the original VMAT beam. The original plans were delivered on an Elekta Versa HD and measured with Mapcheck2 using an in-house developed subarc method. For both the isodose distribution and DVH, there were significant differences between the original VMAT plan and either the SW or the interpolated plan. However, they were indistinguishable between the SW and interpolated plans. The average passing rate between the original VMAT plan and measurements was 84%. For both the interpolated and SW plans, the average passing rate was 96%. We conclude that the proposed SW approach improves VMAT dose calculation accuracy without increase in dose calculation time.
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U2 - 10.1088/1742-6596/1305/1/012065
DO - 10.1088/1742-6596/1305/1/012065
M3 - Conference article
AN - SCOPUS:85073615043
SN - 1742-6588
VL - 1305
JO - Journal of Physics: Conference Series
JF - Journal of Physics: Conference Series
IS - 1
M1 - 012065
T2 - 10th International Conference on 3D Radiation Dosimetry, IC3DDose 2018
Y2 - 16 September 2018 through 19 September 2018
ER -