A Review on the Use of Grid-Based Boltzmann Equation Solvers for Dose Calculation in External Photon Beam Treatment Planning
Table 1
A summary describing information of some previous investigations for the accuracy of D-LBTE solvers in predicting the doses in heterogeneous simple geometric phantoms using single open fields.
One multilayer phantom: water (0–3 cm), aluminium, Al (3–5 cm), lung (5–12 cm), water (12–30 cm)
One multilayer phantom: water (0–3 cm), bone (3–5 cm), lung (5–12 cm), water (12–30 cm)
Two phantoms: (i) one with a single insert of normal lung, light lung, or air in water, (ii) a bone/lung phantom with several disk-shaped bony structures
One multilayer phantom: water (0–3 cm), bone (3–5 cm), lung (5–12 cm), water (12–30 cm)
cm3 of water containing cm3 of air
cm3 of muscle cube containing cm3 of stainless steel or titanium alloy
Difference between D-LBTE solver and Monte Carlo simulation
Average discrepancy is 1.4%, with 2.2% maximum discrepancy observed at water/Al interface
For 6 MV, max. discrepancy < 1.5%, with DTA < 0.7 mm in the build-up region. For 18 MV, max. discrepancy < 2.3% with DTA < 0.3 mm in the build-up region
Discrepancies were within 2% in lung, 3% in light lung, up to 4.5% in air, 1.8% in bone, with slightly larger discrepancy (up to 5%) at interfaces
For 6 MV, average discrepancy of 1.1% in PDD and 1.6% in dose profiles. For 18 MV, average discrepancy of 1.6% in PDD and 3.0% and dose profiles
Discrepancies are mostly within 2%, with slightly higher discrepancy (up to 6%) at the air/tissue interface in the secondary build-up region
In general good agreement between AXB and MC, with an average gamma agreement with a 2%/1mm criteria of 91.3% to 96.8%