# Dose Calculation Algorithms for External Radiation Therapy: An Overview for Practitioners
## 5 Calculation Algorithm Possibilities in Commercial Treatment Planning Systems
### RayStation System  
The RayStation system (RaySearch Laboratories, Stockholm, Sweden) is the most versatile treatment planning system to date, usable for photon, electron, proton, and carbon ion dose calculations and planning. RayStation can be used to plan for electrons/photons on LINACs, for photons on Accuray's Helical TomoTherapy system [89], and for protons and carbon ions on various delivery systems.  
RayStation uses both the collapsed cone convolution (CCC) and Monte Carlo (MC) algorithms for photon beams. It is supplied by a GPU-based dose engine [90] to speed up the calculation time. RayStation uses the VMC++ code, a C++ re-implementation of the VMC and XVMC code systems for electron beam dose calculations. The VMC++ code is optimized for 3D dose calculations in voxel geometries [91].  
RayStation also supports planning for proton pencil beam scanning (PBS), line scanning (LS), uniform scanning (US), double scattering (DS), and wobbling proton beam delivery systems. For PBS/LS beams, RayStation offers two clinical dose engines--one based on the PBA and the other on the MC. MC is especially recommended for patients/cases with large inhomogeneities [92] and is available for beams collimated by blocks or multileaf collimators (MLCs). For US, DS and Wobbling beams, RayStation offers a clinical dose engine based on the PBA. The light ion dose calculation in RayStation is based on PBA. The computation of RBE-weighted values is implemented according to the local effect model (LEM) or to the microdosimetric kinetic model (MKM) [93; 94].  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline  & & \multicolumn{10}{c}{**Calculation Algorithms**} \\ \hline \multirow{2}{*}{**TPS**} & \multicolumn{4}{c}{**Photon Beams**} & \multicolumn{4}{c}{**Electron Beams**} & \multicolumn{4}{c}{**Proton Beams**} & \multicolumn{4}{c}{**Ion Beams**} \\ \cline{2-13}  & **PBC** & **CCC** & **AAA** & **AXB** & **MC** & **GGPB** & **PBA** & **MC** & **PBA** & **PCS** & **APT** & **MC** & **PBA** \\ \hline Ray Station & & \(\surd\) & & & \(\surd\) & & & \(\surd\) & & & \(\surd\) & & \(\surd\) & \(\surd\) \\ Pinnacle & & \(\surd\) & & & & \(\surd\) & & \(\surd\) & & \(\surd\) & & & \(\surd\) & & \\ Eclipse & \(\surd\) & & \(\surd\) & & & \(\surd\) & & \(\surd\) & & \(\surd\) & & & \\ Monaco & & \(\surd\) & & & \(\surd\) & & & \(\surd\) & & & & & \\ XiO & & & & & & & & & \(\surd\) & & & & \\ Elements & & & & & & & & & & & & \\ MBM & \(\surd\) & & & & \(\surd\) & & & & & & & & \\ \hline \hline \end{tabular} Abbreviations: PBC: pencil beam convolution; CCC: collapsed cone convolution; AAA: analytical anisotropic algorithm; AXB: Acuros external beam; MC: Monte Carlo; GGPB: generalized Gaussian pencil beam; PBA: pencil beam algorithm; PCS: proton convolution superposition; APT: Acuros proton therapy; MBM: multiple brain metastases.  
\end{table}
Table 1: Main commercial treatment planning systems available and their respective algorithm options for photon, electron, proton and ion beams.