{"created":"2023-05-15T14:34:39.352609+00:00","id":44787,"links":{},"metadata":{"_buckets":{"deposit":"0c3ab2cf-cec6-4f4e-9c51-5697c2427f44"},"_deposit":{"created_by":1,"id":"44787","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"44787"},"status":"published"},"_oai":{"id":"oai:repo.qst.go.jp:00044787","sets":["1"]},"author_link":["444720","444718","444716","444719","444717"],"item_8_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2006-10","bibliographicIssueDateType":"Issued"},"bibliographicIssueNumber":"20","bibliographicPageEnd":"5244","bibliographicPageStart":"5231","bibliographicVolumeNumber":"51","bibliographic_titles":[{"bibliographic_title":"Physics in Medicine and Biology"}]}]},"item_8_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Purpose: Respiratory-gated CT (RGCT) and four-dimensional CT (4DCT) scan techniques cover consecutive segments of the respiratory cycle. However, motion artifacts may occur in fast respiratory phases such as mid-inhalation and -exhalation. CT imaging involves the use of a number of x-ray tube positions for each couch position. We investigated the fundamental nature of motion artifacts using a constant-velocity moving phantom in motion in the CT plane or perpendicular to the CT plane, and in pigs to simulate a human model.\nMethods and Materials: Artifacts and movement distance were evaluated in a moving phantom and artificially ventilated pigs with a 256-multi-detector row CT (256MDCT). The phantom moved in the CT plane or perpendicular to the CT plane with a constant velocity. Backprojection used variable initial Backprojection angles (IBAs). \nResults: Phantom length for motion perpendicular to the CT plane was independent of IBA but was represented by phantom diameter plus the distance of movement per gantry rotation. In contrast, that for motion in the CT plane was dependent on IBA, as represented by phantom diameter plus the distance of movement per rotation for IBA perpendicular to the phantom movement direction, and phantom diameter plus half the distance of movement per gantry rotation for other IBAs. Results for volumetric CT images with different IBAs showed the presence of banding artifacts. Similar findings were seen in artificially ventilated pigs.\nConclusions: Motion artifacts are unavoidable in both conventional CT and 256MDCT. Banding artifacts will be improved if the same IBAs at each couch position are accounted for during image reconstruction. This improvement will be beneficial in respiratory gated and 4D radiation therapies.","subitem_description_type":"Abstract"}]},"item_8_source_id_9":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"0031-9155","subitem_source_identifier_type":"ISSN"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"metadata only access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_14cb"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"Mori, Shinichiro"}],"nameIdentifiers":[{"nameIdentifier":"444716","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Endo, Masahiro"}],"nameIdentifiers":[{"nameIdentifier":"444717","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Asakura, Hiroshi"}],"nameIdentifiers":[{"nameIdentifier":"444718","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"森 慎一郎","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"444719","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"遠藤 真広","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"444720","nameIdentifierScheme":"WEKO"}]}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"journal article","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_title":"Improvement in banding artefacts in four-dimensional computed tomography for radiotherapy planning","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Improvement in banding artefacts in four-dimensional computed tomography for radiotherapy planning"}]},"item_type_id":"8","owner":"1","path":["1"],"pubdate":{"attribute_name":"公開日","attribute_value":"2007-02-09"},"publish_date":"2007-02-09","publish_status":"0","recid":"44787","relation_version_is_last":true,"title":["Improvement in banding artefacts in four-dimensional computed tomography for radiotherapy planning"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2023-05-16T00:11:20.650807+00:00"}