{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T03:02:01Z","timestamp":1789700521311,"version":"4.0.1"},"reference-count":10,"publisher":"Wiley","issue":"9","license":[{"start":{"date-parts":[[2026,8,24]],"date-time":"2026-08-24T00:00:00Z","timestamp":1787529600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,8,24]],"date-time":"2026-08-24T00:00:00Z","timestamp":1787529600000},"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":[[2026,9]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>To evaluate the reproducibility and precision of CT beam width measurements using a pencil ionization chamber and radiopaque mask and to assess the robustness of the technique against clinically realistic setup errors in the superior\u2010inferior (SI) and anterior\u2010posterior (AP) directions.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Beam width was measured on a GE Discovery RT590 CT scanner at three nominal collimations (10, 15, 20\u00a0mm), three tube potentials (80, 100, 120\u00a0kV), and three tube currents (50, 100, 150\u00a0mA). Three repeated exposures per setting were acquired using a Radcal Accu\u2010Gold pencil ionization chamber with a radiopaque mask to calculate beam width. Coefficients of variation and Levene's test were used to test precision. To assess the robustness to setup error, the chamber was offset from the isocenter at 0, 1, 3, and 5\u00a0mm in the SI direction at 20\u2010mm collimation across all kV\/mA combinations and at 0 and 5\u00a0mm in the AP direction at 10\u2010 and 20\u2010mm collimation. A linear mixed\u2010effects model was used to test the sensitivity of beam width to SI setup errors across kV\/mA combinations. Slopes of the overall deviance from the global mean vs offset were obtained for each combination with 95% confidence intervals, and pairwise slope differences were evaluated using a Tukey\u2010adjusted statistical test. Confidence intervals were used to assess AP setup errors at two different nominal collimations.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Across all kV\/mA combinations, mean measured radiation beam width was 13.04, 16.90, and 20.60\u00a0mm for nominal 10\u2010, 15\u2010, and 20\u2010mm collimations, with inter\u2010protocol coefficients of variation of 0.57%, 0.48%, and 0.25%, respectively. Intra\u2010protocol standard deviations across triplicate exposures were 0.04 to 0.09\u00a0mm. SI offset slopes from 0 \u2013 3\u00a0mm ranged from \u22120.07 to \u22120.12\u00a0mm (per mm of offset) with overlapping 95% confidence intervals. There was no significant interaction with kV\/mA (\n                      <jats:italic>p<\/jats:italic>\n                      \u00a0&gt;\u00a00.05). AP offsets of 5\u00a0mm produced beam\u2010width changes of 0.09\u00a0mm at 10\u00a0mm collimation and 0.15\u00a0mm at 20\u00a0mm collimation.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>The pencil ionization chamber and radiopaque mask technique produced highly reproducible CT beam width estimates for potentials up to 120\u00a0kV and at or above 50\u00a0mA that were independent of tube potential, tube current, and robust to clinically plausible setup inconsistencies.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/acm2.70753","type":"journal-article","created":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T06:47:43Z","timestamp":1787640463000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Reproducibility and positioning sensitivity of CT beam width measurements using a pencil ionization chamber and radiopaque mask"],"prefix":"10.1002","volume":"27","author":[{"given":"Morgan","family":"Aire","sequence":"first","affiliation":[{"name":"Department of Physics and Astronomy Louisiana State University  Baton Rouge Louisiana USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hunter C.","family":"Meyer","sequence":"additional","affiliation":[{"name":"Department of Physics and Astronomy Louisiana State University  Baton Rouge Louisiana USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Krystal","family":"Kirby","sequence":"additional","affiliation":[{"name":"Department of Physics and Astronomy Louisiana State University  Baton Rouge Louisiana USA"},{"name":"Department of Radiation Oncology Mary Bird Perkins Cancer Center  Baton Rouge Louisiana USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,8,24]]},"reference":[{"key":"e_1_2_9_2_1","unstructured":"DillonC WilliamB ClementsJ et\u00a0al.2017 Computed Tomography Quality Control Manual.2017.https:\/\/www.scribd.com\/document\/417505172\/CT\u2010QCManual\u2010pdf"},{"key":"e_1_2_9_3_1","doi-asserted-by":"publisher","DOI":"10.1002\/mp.13763"},{"key":"e_1_2_9_4_1","doi-asserted-by":"publisher","DOI":"10.1093\/rpd\/ncq078"},{"key":"e_1_2_9_5_1","doi-asserted-by":"publisher","DOI":"10.1120\/jacmp.v14i4.4122"},{"key":"e_1_2_9_6_1","doi-asserted-by":"publisher","DOI":"10.1002\/mp.14497"},{"key":"e_1_2_9_7_1","doi-asserted-by":"publisher","DOI":"10.1002\/mp.12227"},{"key":"e_1_2_9_8_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.4914396"},{"key":"e_1_2_9_9_1","doi-asserted-by":"publisher","DOI":"10.1002\/acm2.70027"},{"key":"e_1_2_9_10_1","doi-asserted-by":"publisher","DOI":"10.1002\/mp.12525"},{"key":"e_1_2_9_11_1","doi-asserted-by":"publisher","DOI":"10.1002\/acm2.12670"}],"container-title":["Journal of Applied Clinical Medical Physics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/aapm.onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/acm2.70753","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/aapm.onlinelibrary.wiley.com\/doi\/full-xml\/10.1002\/acm2.70753","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/aapm.onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/acm2.70753","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T02:06:43Z","timestamp":1789697203000},"score":1,"resource":{"primary":{"URL":"https:\/\/aapm.onlinelibrary.wiley.com\/doi\/10.1002\/acm2.70753"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,24]]},"references-count":10,"journal-issue":{"issue":"9","published-print":{"date-parts":[[2026,9]]}},"alternative-id":["10.1002\/acm2.70753"],"URL":"https:\/\/doi.org\/10.1002\/acm2.70753","archive":["Portico"],"relation":{},"ISSN":["1526-9914","1526-9914"],"issn-type":[{"value":"1526-9914","type":"print"},{"value":"1526-9914","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,24]]},"assertion":[{"value":"2026-05-04","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-08-05","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-08-24","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e70753"}}