Can megavoltage computed tomography reduce proton range uncertainties in treatment plans for patients with large metal implants?

摘要: Treatment planning calculations for proton therapy require an accurate knowledge of radiological path length, or range, to the distal edge target volume. In most cases, range may be calculated with sufficient accuracy using kilovoltage (kV) computed tomography (CT) images. However, metal implants such as hip prostheses can cause severe streak artifacts that lead large uncertainties in range. The purposes this study were quantify streak-related errors and determine if they could avoided by artifact-free megavoltage (MV) CT images treatment planning. Proton plans prepared a rigid, heterogeneous phantom prostate cancer patient prosthesis corrected uncorrected kVCT alone, MVCT combination registered (the hybrid approach). Streak-induced 5–12 mm present kVCT-based plan. Correcting streaks manually assigning estimated true Hounsfield units improved accuracy. rigid phantom, implant-related uncertainty was at <3 both plan MVCT-based approach yielded best overall result. approach, provided good delineation soft tissues due high-contrast resolution, streak-free smaller because did not artifact correction.