Using Megavoltage Computed Tomography to Estimate Radiotherapy Dose for High-Density Metallic Implants

摘要: Streak artifacts in kilovoltage computed tomography (kVCT), originated from metallic implants, are reduced by megavoltage CT (MVCT). This study aimed to establish the image value-to-density table (IVDT) of MVCT and validate dose accuracy. The IVDT was established with different physical densities (0.290–19.427 g/cm3) compared kVCT for doses. Acuros external beam (AXB) algorithm analytical anisotropic (AAA) heterogeneity correction MVCT. Based on experimental results, showed good linearity. Dose overestimations hip prosthesis a water phantom were 2.6%/2.8% kVCT_AAA, 1.8%/−0.7% MVCT_AAA −0.7%/−0.3% MVCT_AXB 6-MV/10-MV photons, respectively. predictive formulas validated highly correlated measured doses ( $R^{2}= 0.9933$ /0.9862 6-/10-MV respectively). On average, differences eye shield Alderson radiation therapy using 6-MV photon 3.6% kVCT_AAA −1% MVCT_AAA. In patient studies, reductions 28.6% 7.4% −3.9% dental fillings, 13.6% −9% −9.1% unilateral prosthesis, −25.3% −5.9% −4.3% bilateral prostheses MVCT_AAA, MVCT_AXB, conclusion, AXB reduces metal plans accurate