title: PATIENT EXPOSURE OPTIMISATION THROUGH TASK-BASED ASSESSMENT OF A NEW MODEL-BASED ITERATIVE RECONSTRUCTION TECHNIQUE.
abstract: The goal of the present work was to report and investigate the performances of a new iterative reconstruction algorithm, using a model observer. For that, a dedicated low-contrast phantom containing different targets was scanned at four volume computed tomography dose index (CTDIvol) levels on a Siemens SOMATOM Force computed tomography (CT). The acquired images were reconstructed using the ADMIRE algorithm and were then assessed by three human observers who performed alternative forced choice experiments. Next, a channelised hotelling observer model was applied on the same set of images. The comparison between the two was performed using the percentage correct as a figure of merit. The results indicated a strong agreement between human and model observer as well as an improvement in the low-contrast detection when switching from an ADMIRE strength of 1-3. Good results were also observed even in situations where the target was hard to detect, suggesting that patient dose could be further reduced and optimised.
authors.affiliation: Institute of Radiation Physics, CHUV, Lausanne, Switzerland julien.ott@chuv.ch.
authors.forename: Julien G
authors.initials: JG
authors.lastname: Ott
authors.affiliation: Institute of Radiation Physics, CHUV, Lausanne, Switzerland.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Ba
authors.affiliation: Institute of Radiation Physics, CHUV, Lausanne, Switzerland.
authors.forename: Damien
authors.initials: D
authors.lastname: Racine
authors.affiliation: Institute of Radiation Physics, CHUV, Lausanne, Switzerland.
authors.forename: Nick
authors.initials: N
authors.lastname: Ryckx
authors.affiliation: Institute of Radiation Physics, CHUV, Lausanne, Switzerland.
authors.forename: François O
authors.initials: FO
authors.lastname: Bochud
authors.affiliation: Institute of Diagnostic and Interventional Radiology, USZ, Zürich, Switzerland.
authors.forename: Hatem
authors.initials: H
authors.lastname: Alkadhi
authors.affiliation: Institute of Radiation Physics, CHUV, Lausanne, Switzerland.
authors.forename: Francis R
authors.initials: FR
authors.lastname: Verdun