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Improvement of Beam-Quality Evaluation Method for Medical Linear Accelerator Using Magnetic Field
Beam-quality of medical linac evaluations vary by diverse factors. Because conventional beam-quality
evaluation methods yield fragmentary results, a new beam-evaluation method is suggested, and its feasibility is evaluated. The PDDs (percentage depth doses) of 6 MV (Mega-voltage) and 10 MV photon, R (Range) of a 6 MeV (Mega Electron-voltage) and 9 MeV electron were measured and compared with the conventional evaluation methods, and the improved methods PDD105, PDD2010, PDD3020, PDD205, PDD3010, and R7050, R5030, R7030 as the magnetic field of the bending magnet was changed to +2% to −2%, and the results were compared. The comparison showed that the improved methods exhibit a higher discrimination than the conventional methods in each energy regime. PDD105, PDD3020, PDD3010 and R7050, R5030 should be applied. These methods exhibit a higher discrimination in each energy regime than conventional beam-quality evaluation methods; therefore, they should be used for beam-quality evaluation according to the magnetic field variation.