{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,2,21]],"date-time":"2025-02-21T08:47:47Z","timestamp":1740127667827,"version":"3.37.3"},"reference-count":17,"publisher":"Wiley","issue":"6","license":[{"start":{"date-parts":[[2017,9,12]],"date-time":"2017-09-12T00:00:00Z","timestamp":1505174400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100010236","name":"Tokyo Metropolitan University","doi-asserted-by":"crossref","award":["GC215, 2016"],"award-info":[{"award-number":["GC215, 2016"]}],"id":[{"id":"10.13039\/501100010236","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Applied Clin Med Phys"],"published-print":{"date-parts":[[2017,11]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>For patient setup of the <jats:styled-content style=\"fixed-case\">IGRT<\/jats:styled-content> technique, various imaging systems are currently available. <jats:styled-content style=\"fixed-case\">MV<\/jats:styled-content> portal imaging is performed in identical geometry with the treatment beam so that the portal image provides accurate geometric information. However, <jats:styled-content style=\"fixed-case\">MV<\/jats:styled-content> imaging suffers from poor image contrast due to larger Compton scatter photons. In this work, an original image processing algorithm is proposed to improve and enhance the image contrast without increasing the imaging dose. Scatter estimation was performed in detail by <jats:styled-content style=\"fixed-case\">MC<\/jats:styled-content> simulation based on patient <jats:styled-content style=\"fixed-case\">CT<\/jats:styled-content> data. In the image processing, scatter photons were eliminated and then they were reprojected as primary photons on the assumption that Compton interaction did not take place. To improve the processing efficiency, the dose spread function within the <jats:styled-content style=\"fixed-case\">EPID<\/jats:styled-content> was investigated and implemented on the developed code. Portal images with and without the proposed image processing were evaluated by the image contrast profile. By the subtraction process, the image contrast was improved but the <jats:styled-content style=\"fixed-case\">EPID<\/jats:styled-content> signal was weakened because 15.2% of the signal was eliminated due to the contribution of scatter photons. Hence, these scatter photons were reprojected in the reprojection process. As a result, the tumor, bronchi, mediastinal space and ribs were observed more clearly than in the original image. It was clarified that image processing with the dose spread functions provides stronger contrast enhancement while maintaining a sufficient signal\u2010to\u2010noise ratio. This work shows the feasibility of improving and enhancing the contrast of portal images.<\/jats:p>","DOI":"10.1002\/acm2.12181","type":"journal-article","created":{"date-parts":[[2017,9,12]],"date-time":"2017-09-12T05:18:27Z","timestamp":1505193507000},"page":"71-78","source":"Crossref","is-referenced-by-count":5,"title":["Contrast enhancement for portal images by combination of subtraction and reprojection processes for Compton scattering"],"prefix":"10.1002","volume":"18","author":[{"given":"Masatsugu","family":"Hariu","sequence":"first","affiliation":[{"name":"Graduate School of Human Health Sciences Tokyo Metropolitan University Tokyo Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuhi","family":"Suda","sequence":"additional","affiliation":[{"name":"Graduate School of Human Health Sciences Tokyo Metropolitan University Tokyo Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Weishan","family":"Chang","sequence":"additional","affiliation":[{"name":"Graduate School of Human Health Sciences Tokyo Metropolitan University Tokyo Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Atsushi","family":"Myojoyama","sequence":"additional","affiliation":[{"name":"Graduate School of Human Health Sciences Tokyo Metropolitan University Tokyo Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hidetoshi","family":"Saitoh","sequence":"additional","affiliation":[{"name":"Graduate School of Human Health Sciences Tokyo Metropolitan University Tokyo Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2017,9,12]]},"reference":[{"key":"e_1_2_8_2_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.2775667"},{"key":"e_1_2_8_3_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.3690466"},{"key":"e_1_2_8_4_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0360-3016(99)00118-2"},{"key":"e_1_2_8_5_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.2143141"},{"key":"e_1_2_8_6_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.2362872"},{"key":"e_1_2_8_7_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.2799489"},{"key":"e_1_2_8_8_1","unstructured":"AmericanAssociation of Physicists in Medicine(AAPM).The role of in\u2010room kV X\u2010Ray imaging for patient setup and target localization report of AAPM task group 104. 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