{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T14:02:16Z","timestamp":1789740136163,"version":"4.0.1"},"reference-count":29,"publisher":"Wiley","issue":"8","license":[{"start":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T00:00:00Z","timestamp":1785974400000},"content-version":"vor","delay-in-days":5,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,8,1]],"date-time":"2026-08-01T00:00:00Z","timestamp":1785542400000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["aapm.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["J Applied Clin Med Phys"],"published-print":{"date-parts":[[2026,8]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Multi\u2010energy computed tomography (MECT) and electron density (ED) phantoms are designed for evaluating the performance of CT scanners. They include substitute materials representing the energy\u2010 and material\u2010dependent CT numbers of different organs, tissues, or contrast agents. While MECT phantoms are intended for dual\u2010energy CT (DECT) and photon\u2010counting CT (PCCT) applications, ED phantoms are meant for the calibration of CT numbers to a metric relevant for radiation therapy treatment planning.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>To compare three standard commercial phantoms in terms of iodine quantification for diagnostic imaging and tissue substitute characterization for radiation therapy. The phantoms investigated include the Multi\u2010Energy CT\/Advanced Electron Density Phantom (AED) by Sun Nuclear Corporation (Melbourne, FL, USA), the CIRS Model 662\/062M phantom (Norfolk, VA, USA), and the newly introduced Multi\u2010Energy QA Phantom by QRM (M\u00f6hrendorf, Germany), for which we report the first evaluation results.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>The phantoms were imaged using a GE Revolution Apex DECT scanner (GE Healthcare, Waukesha, WI, USA), a Siemens SOMATOM X.ceed DECT scanner (Siemens Healthineers, Forchheim, Germany), and a Siemens NAEOTOM Alpha PCCT scanner. Iodine\u2010in\u2010water inserts were evaluated using virtual monochromatic images and iodine maps, whereas the tissue equivalence of four insert sets (AED, CIRS\u2010ED, CIRS\u2010EPTN, and QRM) was theoretically assessed. For this purpose, vendor\u2010specified elemental compositions and physical mass densities were used to derive relative electron density (RED), effective atomic number (EAN), mean excitation energy (I\u2010value), and mass density (MD), which were then compared with corresponding human tissues listed in ICRU Report 44. CT scans of the phantoms containing these tissue substitutes were subsequently used for CT number calibration to proton stopping power\u2010ratio (SPR), RED, and MD.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Fitted slopes for reconstructed iodine concentrations were accurate to within 8% for the QRM and AED phantom inserts. For the best performing scanner (PCCT), the slope was within 3%. The CIRS iodine\u2010in\u2010water inserts showed substantially higher deviations of up to 22%. Linear attenuation coefficients derived from 70 keV virtual monochromatic images generally agreed with theoretically expected values to within about 10% for the QRM and AED iodine inserts (for concentrations of 1 mg\/mL or higher). Regarding the QRM, AED and CIRS\u2010EPTN tissue substitute sets: they were closely tissue\u2010equivalent in terms of RED, EAN, I\u2010value (and hence SPR), but not in terms of MD. The CIRS\u2010ED inserts were not, however, closely tissue\u2010equivalent in terms of EAN. Consequently, the QRM, AED and CIRS\u2010EPTN substitutes satisfy the consensus guide criteria of the European proton therapy community for CT calibration, whereas the CIRS\u2010ED set does not.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>The commercially available phantoms of Sun Nuclear (AED) and QRM are suitable for both MECT performance assessment and CT\u2010calibration for radiation therapy. However, the batch of CIRS iodine\u2010in\u2010water inserts used in this study was unsuitable for MECT assessment. Also, the tissue substitute set provided with the CIRS 062M ED phantom was less tissue\u2010equivalent than the other sets\u00a0evaluated.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/acm2.70735","type":"journal-article","created":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T12:59:28Z","timestamp":1786021168000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Comparison of three commercial multi\u2010energy CT and electron density phantoms for iodine quantification and tissue substitute characterization"],"prefix":"10.1002","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2643-7994","authenticated-orcid":false,"given":"Artur","family":"Omar","sequence":"first","affiliation":[{"name":"Medical Radiation Physics and Nuclear Medicine Karolinska University Hospital Stockholm Sweden"},{"name":"Department of Clinical Science Intervention and Technology Karolinska Institutet Stockholm 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