title: The CT number accuracy of a novel commercial metal artifact reduction algorithm for large orthopedic implants.
abstract: Philips Healthcare released a novel metal artifact reduction algorithm for large orthopedic implants (O-MAR). Little information was available about its CT number accuracy. Since CT numbers are used for tissue heterogeneity corrections in external beam radiotherapy treatment planning, we performed a phantom study to assess the CT number accuracy of O-MAR. Two situations were simulated: a patient with a unilateral metallic hip prosthesis and a patient with bilateral metallic hip prostheses. We compared the CT numbers in the O-MAR reconstructions of the simulations to those in the nonO-MAR reconstruction and to those in a metal-free baseline reconstruction. In both simulations, the CT number accuracy of the O-MAR reconstruction was better than the CT number accuracy of the nonO- MAR reconstruction. In the O-MAR reconstruction of the unilateral simulation, all CT numbers were accurate within ± 5 HU (AAPM criterion). In the O-MAR reconstruction of the bilateral simulation, CT numbers were found that differed more than ± 5 HU from the metal-free baseline values. However, none of these differences were clinically relevant.
authors.affiliation: Radiotherapeutic Institute RISO. g.hilgers@risomail.nl.
authors.forename: Guido
authors.initials: G
authors.lastname: Hilgers
authors.forename: Tonnis
authors.initials: T
authors.lastname: Nuver
authors.forename: André
authors.initials: A
authors.lastname: Minken
mesh_terms: D000465:Algorithms; D016477:Artifacts; D003198:Computer Simulation; D006622:Hip Prosthesis; D006801:Humans; D008670:Metals; D019047:Phantoms, Imaging; D019736:Prostheses and Implants; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D008670:Metals