{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,21]],"date-time":"2026-01-21T16:25:37Z","timestamp":1769012737980,"version":"3.49.0"},"reference-count":25,"publisher":"Wiley","issue":"10","license":[{"start":{"date-parts":[[2019,10,2]],"date-time":"2019-10-02T00:00:00Z","timestamp":1569974400000},"content-version":"vor","delay-in-days":1,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100007880","name":"Johns Hopkins University","doi-asserted-by":"publisher","award":["5T32GM007057\u201042"],"award-info":[{"award-number":["5T32GM007057\u201042"]}],"id":[{"id":"10.13039\/100007880","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["aapm.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["J Applied Clin Med Phys"],"published-print":{"date-parts":[[2019,10]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Purpose<\/jats:title><jats:p>The imaging performance and dose of a mobile CT scanner (Brainlab Airo\u00ae, Munich, Germany) is evaluated, with particular consideration to assessment of technique protocols for image\u2010guided brachytherapy.<\/jats:p><\/jats:sec><jats:sec><jats:title>Method<\/jats:title><jats:p>Dose measurements were performed using a 100\u2010mm\u2010length\u00a0pencil chamber at the center and periphery of 16\u2010 and 32\u2010cm\u2010diameter CTDI phantoms. Hounsfield unit (HU) accuracy and linearity were assessed using materials of specified electron density (Gammex RMI, Madison, WI), and image uniformity, noise, and noise\u2010power spectrum (NPS) were evaluated in a 20\u2010cm\u2010diameter water phantom as well as an American College of Radiology (ACR) CT accreditation phantom (Model 464, Sun Nuclear, Melbourne, FL). Spatial resolution (modulation transfer function, MTF) was assessed with an edge\u2010spread phantom and visually assessed with respect to line\u2010pair patterns in the ACR phantom and in structures of interest in anthropomorphic phantoms. Images were also obtained on a diagnostic CT scanner (Big Bore CT simulator, Philips, Amsterdam, Netherlands) for qualitative and quantitative comparison. The manufacturer\u2019s metal artifact reduction (MAR) algorithm was assessed in an anthropomorphic body phantom containing surgical instrumentation. Performance in application to brachytherapy was assessed with a set of anthropomorphic brachytherapy phantoms \u2014 for example, a vaginal cylinder and interstitial ring and tandem.<\/jats:p><\/jats:sec><jats:sec><jats:title>Result<\/jats:title><jats:p>Nominal dose for helical and axial modes, respectively, was 56.4 and 78.9\u00a0mGy for the head protocol and 17.8 and 24.9\u00a0mGy for the body protocol. A high degree of HU accuracy and linearity was observed for both axial and helical scan modes. Image nonuniformity (e.g., cupping artifact) in the transverse (<jats:italic>x<\/jats:italic>,<jats:italic>y<\/jats:italic>) plane was less than 5\u00a0HU, but stitching artifacts (~5\u00a0HU) in the longitudinal (<jats:italic>z<\/jats:italic>) direction were observed in axial scan mode. Helical and axial modes demonstrated comparable spatial resolution of\u00a0~5\u00a0lp\/cm, with the MTF reduced to 10% at\u00a0~0.38\u00a0mm<jats:sup>\u22121<\/jats:sup>. Contrast\u2010to\u2010noise ratio was suitable to soft\u2010tissue visualization (e.g., fat and muscle), but windmill artifacts were observed in helical mode in relation to high\u2010frequency bone and metal. The MAR algorithm provided modest improvement to image quality. Overall, image quality appeared suitable to relevant clinical tasks in intracavitary and interstitial (e.g., gynecological) brachytherapy, including visualization of soft\u2010tissue structures in proximity to the applicators.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>The technical assessment highlighted key characteristics of dose and imaging performance pertinent to incorporation of the mobile CT scanner in clinical procedures, helping to inform clinical deployment and technique protocol selection in brachytherapy. For this and other possible applications, the work helps to identify protocols that could reduce radiation dose and\/or improve image quality. The work also identified areas for future improvement, including reduction of stitching, windmill, and metal artifacts.<\/jats:p><\/jats:sec>","DOI":"10.1002\/acm2.12738","type":"journal-article","created":{"date-parts":[[2019,10,3]],"date-time":"2019-10-03T03:16:51Z","timestamp":1570072611000},"page":"187-200","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["Technical assessment of a mobile CT scanner for image\u2010guided brachytherapy"],"prefix":"10.1002","volume":"20","author":[{"given":"Nicole E.","family":"Chernavsky","sequence":"first","affiliation":[{"name":"Department of Biomedical Engineering Johns Hopkins University Baltimore MD USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marc","family":"Morcos","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology and Molecular Radiation Sciences Johns Hopkins University Baltimore MD USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pengwei","family":"Wu","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering Johns Hopkins University Baltimore MD USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Akila N.","family":"Viswanathan","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology and Molecular Radiation Sciences Johns Hopkins University Baltimore MD USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jeffrey H.","family":"Siewerdsen","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering Johns Hopkins University Baltimore MD USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2019,10,2]]},"reference":[{"key":"e_1_2_7_2_1","doi-asserted-by":"publisher","DOI":"10.3233\/XST-150496"},{"key":"e_1_2_7_3_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00586-015-3814-4"},{"key":"e_1_2_7_4_1","doi-asserted-by":"publisher","DOI":"10.3171\/2018.1.SPINE17927"},{"key":"e_1_2_7_5_1","doi-asserted-by":"publisher","DOI":"10.1002\/acm2.12084"},{"key":"e_1_2_7_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.brachy.2011.07.003"},{"key":"e_1_2_7_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.brachy.2011.08.005"},{"key":"e_1_2_7_8_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.brachy.2011.09.008"},{"key":"e_1_2_7_9_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijrobp.2009.01.043"},{"key":"e_1_2_7_10_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.radonc.2016.03.011"},{"key":"e_1_2_7_11_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.radonc.2013.11.002"},{"key":"e_1_2_7_12_1","doi-asserted-by":"publisher","DOI":"10.5114\/jcb.2017.67456"},{"key":"e_1_2_7_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.mri.2012.06.003"},{"key":"e_1_2_7_14_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.3578929"},{"key":"e_1_2_7_15_1","unstructured":"AAPM Task Group 23: CT Dosimetry.The Measurement Reporting and Management of Radiation Dose in CT. 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