Investigations of different kilovoltage X-ray energy for three-dimensional converging stereotactic radiotherapy system; Monte Carlo simulations with CT data

Deloar, H. M.*; Kunieda, Etsuo*; Kawase, Takatsugu*; Tsunoo, Takanori*; Saito, Hidetoshi*; Ozaki, Masahiro*; Saito, Kimiaki; Takagi, Shunji*; Sato, Osamu*; Fujisaki, Tatsuya*; et al.

Medical Physics, 33(12), p.4635 - 4642, 2006/12

https://doi.org/10.1118/1.2361080

We are investigating three-dimensional converging stereotactic radiotherapy for small lung tumors with better dose homogeneity at the target. A computed tomography radiotherapy was simulated with BEAMnrc X-ray energy of 147.5, 200, 300, and 500 kilovoltage system was validated by comparing calculated and measured percentage of depth dose in a water phantom for the energy of 120 and 147.5 kVp. A thorax phantom and CT data from lung tumors compare dose homogeneities of kVp energies with MV energies of 4, 6, and 10 MV. Three non-coplanar arcs of the target were employed. The Monte Carlo dose data format was converted to the XiO RTP format to compare dose homogeneity, differential, and integral dose volume histograms of kVp and MV energies. In terms of dose homogeneity and DVHs, dose distributions at the target of all kVp energies with the thorax phantom were better than MV energies, with mean dose absorption at the ribs of 100%, 85%, 50%, 30% for 147.5, 200, 300, and 500 kVp, respectively. Considering dose distributions and reduction of the enhanced dose absorption at the ribs, a minimum of 500 kVp is suitable for the lung kVp 3DCSRT system.