{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T11:02:32Z","timestamp":1787050952849,"version":"build-2736575974"},"reference-count":41,"publisher":"IOP Publishing","issue":"9","license":[{"start":{"date-parts":[[2026,5,5]],"date-time":"2026-05-05T00:00:00Z","timestamp":1777939200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/publishingsupport.iopscience.iop.org\/iop-standard\/v1"},{"start":{"date-parts":[[2026,5,5]],"date-time":"2026-05-05T00:00:00Z","timestamp":1777939200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/iopscience.iop.org\/info\/page\/text-and-data-mining"}],"content-domain":{"domain":["iopscience.iop.org"],"crossmark-restriction":false},"short-container-title":["Phys. Med. Biol."],"published-print":{"date-parts":[[2026,5,14]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    <jats:italic>Objective.<\/jats:italic>\n                    Computed tomography (CT) number accuracy is critical in radiotherapy planning. This study aimed to investigate the potential of photon-counting-detector (PCD) CT to reduce location dependency of CT numbers compared to energy-integrated-detector (EID) CT across imaging modes, tissue types, and patient sizes.\n                    <jats:italic>Approach.<\/jats:italic>\n                    Four inserts of typical tissue types: cortical bone, liver, lung, and adipose were placed inside a body size (40 \u00d7 30 cm\n                    <jats:sup>2<\/jats:sup>\n                    ) multi-energy CT phantom (Gammex). To simulate a larger patient, tissue-equivalent material (Superflab) was added to increase phantom lateral width to 50 cm. Both phantoms were scanned on a PCD-CT (NAEOTOM Alpha, Siemens), a dual-source EID-CT (Force, Siemens; EID-A), and a dual-layer EID-CT (7500 Spectral, Philips; EID-B). All scans were performed with 120 kV, except dual-energy mode of EID-A (100\/Sn150 kV, Sn: Tin filter). Volume CT dose index (CTDI\n                    <jats:sub>vol<\/jats:sub>\n                    ) was matched across scanners. Each insert was scanned in seven locations: iso-center and six peripheral locations. In addition to single-energy images, 70 keV virtual-monoenergetic images (VMIs) were reconstructed. CT numbers were measured using circular regions of interest. Mean CT number, standard deviation (std), coefficient of variation (CV), max-to-min and central-to-peripheral differences were quantified. CT number variation across seven locations was assessed using the Friedman test and Bonferroni corrected pairwise Wilcoxon signed-rank tests.\n                    <jats:italic>Main results.<\/jats:italic>\n                    PCD-VMI demonstrated lower CT number locational variation compared to EID-CTs among most tissue inserts and phantom sizes. For cortical bone in the standard phantom, PCD-VMI achieved std of 3.31 HU, showing 70.3% reduction compared to single-energy PCD (11.15 HU) and lower than single-energy EID-A (9.75 HU), single-energy EID-B (10.93 HU), EID-A VMI (12.65 HU), and EID-B VMI (4.10 HU). PCD-VMI CV remained below 1% and 3% for small and large phantoms, respectively. Increasing phantom size increased CT number variations, with lowest differences for PCD-VMI. PCD-VMI showed significantly lower CT number locational variation than all other scans across most inserts and phantom sizes.\n                    <jats:italic>Significance.<\/jats:italic>\n                    PCD-VMI reduces CT number locational dependency compared to most imaging modes. The greatest improvements were observed for high-\n                    <jats:italic>Z<\/jats:italic>\n                    materials and larger patients. PCD-VMIs are promising for radiation therapy applications.\n                  <\/jats:p>","DOI":"10.1088\/1361-6560\/ae62f1","type":"journal-article","created":{"date-parts":[[2026,4,21]],"date-time":"2026-04-21T22:57:05Z","timestamp":1776812225000},"page":"095011","update-policy":"https:\/\/doi.org\/10.1088\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["Reduction of CT number location dependency using photon-counting detector CT and virtual monoenergetic imaging"],"prefix":"10.1088","volume":"71","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3663-6011","authenticated-orcid":true,"given":"Maryam","family":"Sadeghian","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joseph R","family":"Swicklik","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cynthia H","family":"McCollough","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8038-0773","authenticated-orcid":true,"given":"Yanle","family":"Hu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6453-9481","authenticated-orcid":true,"given":"Shuai","family":"Leng","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"266","published-online":{"date-parts":[[2026,5,5]]},"reference":[{"key":"pmbae62f1bib1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jrras.2024.100997","type":"journal-article","article-title":"Impact of CT tube voltage variation on calculated dose radiotherapy: a simulation and phantom study","volume":"17","author":"Afifi","year":"2024","journal-title":"J. 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