{"created":"2023-05-15T14:36:00.289535+00:00","id":46338,"links":{},"metadata":{"_buckets":{"deposit":"a375fdfc-c003-4769-a059-7d2c258b2b59"},"_deposit":{"created_by":1,"id":"46338","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"46338"},"status":"published"},"_oai":{"id":"oai:repo.qst.go.jp:00046338","sets":["1"]},"author_link":["461643","461644","461642","461639","461638","461645","461640","461641"],"item_8_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2012-02","bibliographicIssueDateType":"Issued"},"bibliographicIssueNumber":"1","bibliographicPageEnd":"29","bibliographicPageStart":"24","bibliographicVolumeNumber":"59","bibliographic_titles":[{"bibliographic_title":"IEEE Transactions on Nuclear Science"}]}]},"item_8_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Purpose: In the conventional techniques for determining the calibration factors of positron emission tomography (PET) scanners, cylindrical water and resin phantoms with radioisotope 18F or 68Ge/68Ga are used. In these methods, however, the results depend on attenuation and scatter correction. The purpose of this study is to develop a point-like 68Ge/68Ga radioactive source that can be used to determine the calibration factors of PET scanners without the uncertainty of attenuation and scatter correction. Methods: A spherical absorber design was employed to realize a symmetric angular distribution of emitted annihilation photons. A Geant4-based Monte Carlo simulation code was used to compare physics characteristics of point-like sources with various absorber materials. On the basis of this simulation, a point-like 68Ge/68Ga source with a spherical aluminum absorber was manufactured. Its radioactivity was calibrated at an accredited national calibration facility. A calibration factor of a clinical PET scanner was then obtained with a point-like source and compared with that obtained by a standard cross-calibration method. Results: The emission probability of 0.511 MeV annihilation photon pairs per positron decay was typically 0.6-0.8. The fraction of background photon pairs was 6-8% in the energy region of 0.4-0.6 MeV. Considering these two figures, lower density materials such as aluminum and pol(ymethyl methacrylate) (PMMA) were preferable. For the aluminum absorber, a diameter of 8 mm was suitable to prevent positrons from escaping. The calibration factor obtained with the point-like source agreed with that obtained by the standard method within 2-3%. Conclusion: A point-like 68Ge/68Ga radioactive source was successfully designed, manufactured, and used for determining a calibration factor of a PET scanner. It can be considered a practical tool for calibrating and ev- luating the quantitative aspects of PET scanners.","subitem_description_type":"Abstract"}]},"item_8_source_id_9":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"0018-9499","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":"Hasegawa, Tomoyuki"}],"nameIdentifiers":[{"nameIdentifier":"461638","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Oda, Keiichi"}],"nameIdentifiers":[{"nameIdentifier":"461639","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Murayama, Hideo"}],"nameIdentifiers":[{"nameIdentifier":"461640","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Takei, Hideyuki"}],"nameIdentifiers":[{"nameIdentifier":"461641","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"et.al"}],"nameIdentifiers":[{"nameIdentifier":"461642","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"長谷川 智之","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"461643","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"村山 秀雄","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"461644","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"武居 秀行","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"461645","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":"Novel point-like Ge-68/Ga-68 radioactive source with spherical positron absorber","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Novel point-like Ge-68/Ga-68 radioactive source with spherical positron absorber"}]},"item_type_id":"8","owner":"1","path":["1"],"pubdate":{"attribute_name":"公開日","attribute_value":"2012-06-06"},"publish_date":"2012-06-06","publish_status":"0","recid":"46338","relation_version_is_last":true,"title":["Novel point-like Ge-68/Ga-68 radioactive source with spherical positron absorber"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2023-05-15T23:53:02.106857+00:00"}