{"id":2253,"date":"2004-12-02T17:31:10","date_gmt":"2004-12-03T00:31:10","guid":{"rendered":"http:\/\/oralcancernews.org\/wp\/?p=2253"},"modified":"2009-03-25T17:34:46","modified_gmt":"2009-03-26T00:34:46","slug":"head-and-neck-diagnostic-procedures","status":"publish","type":"post","link":"https:\/\/oralcancernews.org\/wp\/head-and-neck-diagnostic-procedures\/","title":{"rendered":"Head and Neck Diagnostic Procedures"},"content":{"rendered":"<ul class=\"bullets\">\n<li><strong>12\/2\/2004<\/strong><\/li>\n<li><strong>Adam S. Jacobson, MD; Mark L. Urken, MD, FACS<\/strong><\/li>\n<li><strong>ACS Surgery: Principles &amp; Practice<\/strong><\/li>\n<\/ul>\n<p><strong>Sources of False Negative PET Scans Using FDG<\/strong><\/p>\n<p>A range of physiologic tracers has been developed for positron emission tomography (PET), with the glucose analogue F-18 fluorodeoxyglucose (FDG) the most commonly used. FDG has a half-life of 110 minutes. Once given to the patient, FDG is taken up by glucose transporters and is phosphorylated by hexokinase to become FDG-6-phosphate (FDG-6-P). Further metabolism of FDG-6-P is blocked by the presence of an extra hydroxyl moiety, which allows FDG-6-P to accumulate in the cell and serve as a marker for glucose metabolism and utilization.<\/p>\n<p>Because FDG is nonspecifically accumulated in glycolytically active cells, it demarcates areas of inflammation as well as neoplastic tissue; this can lead to a false positive scan. Muscular activity during the scan can also lead to areas of increased uptake in nonneoplastic tissue. Furthermore, healing bone, foreign-body granulomas, and paranasal sinus inflammation can produce false positive results.<\/p>\n<p>False negative scans occur when tumor deposits are very small (3 to 4 mm or less in diameter). Thus, micrometastases are not reliably detected using an FDG-PET image. Furthermore, a false negative scan can occur if the PET is performed too soon after radiation therapy.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>12\/2\/2004 Adam S. Jacobson, MD; Mark L. Urken, MD, FACS ACS Surgery: Principles &amp; Practice Sources of False Negative PET Scans Using FDG A range of physiologic tracers has been developed for positron emission tomography (PET), with the glucose analogue F-18 fluorodeoxyglucose (FDG) the most commonly used. FDG has a half-life of 110 minutes. Once given to the patient, FDG is taken up by glucose transporters and is phosphorylated by hexokinase to become FDG-6-phosphate (FDG-6-P). Further metabolism of FDG-6-P is blocked by the presence of an extra hydroxyl moiety, which allows FDG-6-P to accumulate in the cell and serve as a marker for glucose metabolism and utilization. Because FDG is nonspecifically accumulated in glycolytically active cells, it demarcates areas of inflammation as well as neoplastic tissue; this can lead to a false positive scan. Muscular activity during the scan can also lead to areas of increased uptake in nonneoplastic tissue. Furthermore, healing bone, foreign-body granulomas, and paranasal sinus inflammation can produce false positive results. False negative scans occur when tumor deposits are very small (3 to 4 mm or less in diameter). Thus, micrometastases are not reliably detected using an FDG-PET image. Furthermore, a false negative scan can occur if the PET is performed too soon after radiation therapy.<\/p>\n","protected":false},"author":41,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[787],"tags":[],"class_list":["post-2253","post","type-post","status-publish","format-standard","hentry","category-oral-cancer-news-archive"],"_links":{"self":[{"href":"https:\/\/oralcancernews.org\/wp\/wp-json\/wp\/v2\/posts\/2253","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/oralcancernews.org\/wp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/oralcancernews.org\/wp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/oralcancernews.org\/wp\/wp-json\/wp\/v2\/users\/41"}],"replies":[{"embeddable":true,"href":"https:\/\/oralcancernews.org\/wp\/wp-json\/wp\/v2\/comments?post=2253"}],"version-history":[{"count":1,"href":"https:\/\/oralcancernews.org\/wp\/wp-json\/wp\/v2\/posts\/2253\/revisions"}],"predecessor-version":[{"id":2254,"href":"https:\/\/oralcancernews.org\/wp\/wp-json\/wp\/v2\/posts\/2253\/revisions\/2254"}],"wp:attachment":[{"href":"https:\/\/oralcancernews.org\/wp\/wp-json\/wp\/v2\/media?parent=2253"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/oralcancernews.org\/wp\/wp-json\/wp\/v2\/categories?post=2253"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/oralcancernews.org\/wp\/wp-json\/wp\/v2\/tags?post=2253"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}