{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T06:28:30Z","timestamp":1789972110737,"version":"4.0.1"},"reference-count":39,"publisher":"Wiley","issue":"11","license":[{"start":{"date-parts":[[2011,6,2]],"date-time":"2011-06-02T00:00:00Z","timestamp":1306972800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Movement Disorders"],"published-print":{"date-parts":[[2011,9]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Progression of Parkinson's disease symptoms is imperfectly correlated with positron emission tomography biomarkers for dopamine biosynthetic pathways. The radiopharmaceutical 6\u2010[<jats:sup>18<\/jats:sup>F]fluoro\u2010m\u2010tyrosine is not a substrate for catechol\u2010<jats:italic>O<\/jats:italic>\u2010methyltransferase and therefore has a more favorable uptake\u2010to\u2010background ratio than 6\u2010[<jats:sup>18<\/jats:sup>F]fluoro\u2010<jats:sc>L<\/jats:sc>\u2010dopa. The objective of this study was to evaluate 6\u2010[<jats:sup>18<\/jats:sup>F]fluoro\u2010m\u2010tyrosine relative to 6\u2010[<jats:sup>18<\/jats:sup>F]fluoro\u2010<jats:sc>L<\/jats:sc>\u2010dopa with partial catechol\u2010<jats:italic>O<\/jats:italic>\u2010methyltransferase inhibition as a biomarker for clinical status in Parkinson's disease. Twelve patients with early\u2010stage Parkinson's disease, off medication, underwent Unified Parkinson Disease Rating Scale scoring, brain magnetic resonance imaging, and 3\u2010dimensional dynamic positron emission tomography using equivalent doses of 6\u2010[<jats:sup>18<\/jats:sup>F]fluoro\u2010m\u2010tyrosine and 6\u2010[<jats:sup>18<\/jats:sup>F]fluoro\u2010<jats:sc>L<\/jats:sc>\u2010dopa with tolcapone, a catechol\u2010<jats:italic>O<\/jats:italic>\u2010methyltransferase inhibitor. Images were realigned within subject, after which the tissue\u2010derived uptake rate constant was generated for volumes of interest encompassing the caudate nucleus, putamen, and subregions of the putamen. We computed both bivariate (Pearson) and partial (covariate of age) correlations between clinical subscores and tissue\u2010derived uptake rate constant. Tissue\u2010derived uptake rate constant values were correlated between the radiopharmaceuticals (<jats:italic>r<\/jats:italic> = 0.8). Motor subscores were inversely correlated with the contralateral putamen 6\u2010[<jats:sup>18<\/jats:sup>F]fluoro\u2010m\u2010tyrosine tissue\u2010derived uptake rate constant (|r| &gt; 0.72, <jats:italic>P<\/jats:italic> &lt; .005) but not significantly with the 6\u2010[<jats:sup>18<\/jats:sup>F]fluoro\u2010<jats:sc>L<\/jats:sc>\u2010dopa tissue\u2010derived uptake rate constant. The uptake rate constants for both radiopharmaceuticals were also inversely correlated with activities of daily living subscores, but the magnitude of correlation coefficients was greater for 6\u2010[<jats:sup>18<\/jats:sup>F]fluoro\u2010m\u2010tyrosine. In this design, 6\u2010[<jats:sup>18<\/jats:sup>F]fluoro\u2010m\u2010tyrosine uptake better reflected clinical status than did 6\u2010[<jats:sup>18<\/jats:sup>F]fluoro\u2010<jats:sc>L<\/jats:sc>\u2010dopa uptake. We attribute this finding to 6\u2010[<jats:sup>18<\/jats:sup>F]fluoro\u2010m\u2010tyrosine's higher affinity for the target, <jats:sc>L<\/jats:sc>\u2010aromatic amino acid decarboxylase, and the absence of other major determinants of the uptake rate constant. These results also imply that <jats:sc>L<\/jats:sc>\u2010aromatic amino acid decarboxylase activity is a major determinant of clinical status. \u00a9 2011 Movement Disorder Society<\/jats:p>","DOI":"10.1002\/mds.23778","type":"journal-article","created":{"date-parts":[[2011,6,3]],"date-time":"2011-06-03T08:11:06Z","timestamp":1307088666000},"page":"2032-2038","source":"Crossref","is-referenced-by-count":14,"title":["A within\u2010subject comparison of 6\u2010[18F]fluoro\u2010m\u2010tyrosine and 6\u2010[18F]fluoro\u2010<scp>L<\/scp>\u2010dopa in Parkinson's disease"],"prefix":"10.1002","volume":"26","author":[{"given":"Catherine L.","family":"Gallagher","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bradley T.","family":"Christian","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"James E.","family":"Holden","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Onofre T.","family":"Dejesus","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robert J.","family":"Nickles","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Laura","family":"Buyan\u2010Dent","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Barbara B.","family":"Bendlin","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sandra J.","family":"Harding","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Charles K.","family":"Stone","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Barb","family":"Mueller","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sterling C.","family":"Johnson","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2011,6,2]]},"reference":[{"key":"e_1_2_6_2_2","doi-asserted-by":"publisher","DOI":"10.1002\/ana.10609"},{"key":"e_1_2_6_3_2","doi-asserted-by":"publisher","DOI":"10.1002\/mds.10579"},{"key":"e_1_2_6_4_2","doi-asserted-by":"publisher","DOI":"10.1093\/brain\/119.2.585"},{"key":"e_1_2_6_5_2","doi-asserted-by":"publisher","DOI":"10.1097\/00004647-200104000-00015"},{"key":"e_1_2_6_6_2","doi-asserted-by":"publisher","DOI":"10.1097\/00004647-199903000-00006"},{"key":"e_1_2_6_7_2","doi-asserted-by":"publisher","DOI":"10.1016\/0006-8993(92)91518-J"},{"key":"e_1_2_6_8_2","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-4757-9670-4_26"},{"key":"e_1_2_6_9_2","volume-title":"Brain Imaging Using PET","author":"Asselin R","year":"2002"},{"key":"e_1_2_6_10_2","doi-asserted-by":"publisher","DOI":"10.1002\/syn.20016"},{"key":"e_1_2_6_11_2","doi-asserted-by":"publisher","DOI":"10.1212\/01.wnl.0000312381.29287.ff"},{"key":"e_1_2_6_12_2","doi-asserted-by":"publisher","DOI":"10.1155\/2010\/909348"},{"key":"e_1_2_6_13_2","doi-asserted-by":"publisher","DOI":"10.1136\/jnnp.51.6.745"},{"key":"e_1_2_6_14_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1600-0404.2007.00818.x"},{"key":"e_1_2_6_15_2","doi-asserted-by":"publisher","DOI":"10.2165\/00023210-200519020-00006"},{"key":"e_1_2_6_16_2","doi-asserted-by":"publisher","DOI":"10.1016\/0020-708X(84)90194-7"},{"key":"e_1_2_6_17_2","doi-asserted-by":"publisher","DOI":"10.1016\/0969-8043(93)90165-7"},{"key":"e_1_2_6_18_2","doi-asserted-by":"publisher","DOI":"10.1038\/jcbfm.1985.87"},{"key":"e_1_2_6_19_2","doi-asserted-by":"publisher","DOI":"10.1001\/archneur.62.3.467"},{"key":"e_1_2_6_20_2","doi-asserted-by":"publisher","DOI":"10.1002\/mds.1139"},{"key":"e_1_2_6_21_2","first-page":"102S","article-title":"MIRD Pamphlet No. 14 revised: A dynamic urinary bladder model for radiation dose calculations. 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