Purpose: ClearCalc (RADformation, NY) is an independent dose calculation software and has increasingly gained popularity for secondary dose check. This work aims to validate its photon dose calculation algorithm.
Methods: We first created a 10x10 cm² open-field plan irradiating a 30x30x30 cm³ solid water phantom (SW) in Eclipse treatment planning system (TPS,v15.6), with and without a Styrofoam insert. Both the central-axis and off-axis point doses at dmax, 5cm and 10cm depths were measured with pinpoint ion chamber and compared with those from TPS and ClearCalc, respectively. Subsequently, we replaced the above open-field plan with 20 clinical treatment plans, then measured the isocenter doses with ion chamber, and compared the measurements with the corresponding point doses in ClearCalc. Lastly, we randomly selected 91 clinical plans (25 brain, 10 head&neck, 13 breast, 10 lung, 12 abdomen, 11 pelvis, 10 prostate) and retrospectively compared the calculation point doses between TPS and ClearCalc.
Results: In the SW, the average central-axis point dose difference between ClearCalc and measurement for the open-field plans was -0.99%±0.89% (without the insert) and -1.21%±1.34% (with the insert), respectively. The ranges span from -2.41% to 0.34% and from -4.01% to 0.04%, respectively. As to the 20 clinical plans, the average isocenter dose difference between ClearCalc and measurement was -1.27%±7.22% with the range spanning from -13.8% to 18.6%. Additionally, 13 out of 20 plans had agreement within 5%. For 91 clinical plans, the average difference between TPS and ClearCalc was -1.16%±0.43% and the difference range is (-1.46%, 8.76%). Specifically for each individual treatment sites, the difference was -0.22%±0.39% (SRS cone plans), -0.05%±1.26% (brain), 0.52%±1.95% (head&neck), 0.49%±2.59% (breast), 1.90%±1.64% (lung), -0.12%±1.17% (abdomen), 1.14%±1.17% (pelvis), and -0.10%±2.35% (prostate).
Conclusion: ClearCalc photon dose calculations corroborate relatively well with both the treatment planning system and measurement in most cases.
Not Applicable / None Entered.