title: Utility of (99m)Tc-Hynic-TOC in 131I Whole-Body Scan Negative Thyroid Cancer Patients with Elevated Serum Thyroglobulin Levels.
abstract: Several studies have reported on the expression of somatostatin receptors (SSTRs) in patients with differentiated thyroid cancer (DTC). The aim of this study was to evaluate the imaging abilities of a recently developed Technetium-99m labeled somatostatin analog, (99m)Tc-Hynic-TOC, in terms of precise localization of the disease. The study population consisted of 28 patients (16 men, 12 women; age range: 39-72 years) with histologically confirmed DTC, who presented with recurrent or persistent disease as indicated by elevated serum thyroglobulin (Tg) levels after initial treatment (serum Tg > 10 ng/ml off T4 suppression for 4-6 weeks). All patients were negative on the Iodine-131 posttherapy whole-body scans. Fluorine-18 fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) was performed in all patients. SSTR scintigraphy was true positive in 23 cases (82.1%), true negative in two cases (7.1%) and false negative in three cases (10.7%) which resulted in a sensitivity of 88.46%, specificity of 100% and an accuracy of 89.2%. Sensitivity of (99m)Tc-Hynic-TOC scan was higher (93.7%) for patients with advanced stages, that is stages III and IV. (18)F-FDG showed a sensitivity of 93.7%, a specificity of 50% and an accuracy of 89.3%. (18)F-FDG PET was found to be more sensitive, with lower specificity due to false positive results in 2 patients. Analysis on a lesion basis demonstrated substantial agreement between the two imaging techniques with a Cohen's kappa of 0.66. Scintigraphy with (99m)Tc-Hynic-TOC might be a promising tool for treatment planning; it is easy to perform and showed sufficient accuracy for localization diagnostics in thyroid cancer patients with recurrent or metastatic disease.
authors.affiliation: Department of Nuclear Medicine, KMCH, Coimbatore, Tamil Nadu, India.
authors.forename: Ajit S
authors.initials: AS
authors.lastname: Shinto
authors.affiliation: Department of Nuclear Medicine, KMCH, Coimbatore, Tamil Nadu, India.
authors.forename: K K
authors.initials: KK
authors.lastname: Kamaleshwaran
authors.affiliation: Isotope Application and Radiopharmaceuticals Division, BARC, Mumbai, Maharashtra, India.
authors.forename: Madhav
authors.initials: M
authors.lastname: Mallia
authors.affiliation: Isotope Application and Radiopharmaceuticals Division, BARC, Mumbai, Maharashtra, India.
authors.forename: Aruna
authors.initials: A
authors.lastname: Korde
authors.affiliation: Isotope Application and Radiopharmaceuticals Division, BARC, Mumbai, Maharashtra, India.
authors.forename: Grace
authors.initials: G
authors.lastname: Samuel
authors.affiliation: Isotope Application and Radiopharmaceuticals Division, BARC, Mumbai, Maharashtra, India.
authors.forename: Sharmila
authors.initials: S
authors.lastname: Banerjee
authors.affiliation: Department of Nuclear Medicine, KMCH, Coimbatore, Tamil Nadu, India.
authors.forename: Pavanasam
authors.initials: P
authors.lastname: Velayutham
authors.affiliation: Department of Nuclear Medicine, KMCH, Coimbatore, Tamil Nadu, India.
authors.forename: Suresh
authors.initials: S
authors.lastname: Damodharan
authors.affiliation: Department of Nuclear Medicine, KMCH, Coimbatore, Tamil Nadu, India.
authors.forename: Madhu
authors.initials: M
authors.lastname: Sairam
keywords: Fluorodeoxyglucose positron emission tomography; Hynic-TOC; single-photon emission computed tomography; thyroglobulin elevated; thyroid cancer; whole-body scan negative