title: Exploring the role of technitium-99m dimercaptosuccinyl acid (V) scan in medullary carcinoma thyroid patients with postoperative persistent hypercalcitoninemia in the era of positron emission tomography-computerized tomography.
abstract: BACKGROUND
  Many radio-pharmaceuticals have been used over the years to localize the recurrences in patients with medullary carcinoma thyroid (MCT), including iodine-131-metaiodobenzylguanidine, thallium-201, technitium-99m dimercaptosuccinyl acid [Tc-99m DMSA (V)], Tc-99m methoxyisobutylisonitril, Tc-99 ethylenediamine diacetic acid/hydrazinonicotinyl-Tyr (3)-octreotide, and In-111 diethylenetriaminepenta-acetic acid-octreotide with varying sensitivities and specificities.
  
  
  OBJECTIVE
  The aim of this study is to explore the role of Tc-99m DMSA (V) scan in MCT patients with postoperative persistent hypercalcitoninemia in the positron emission tomography-computerized tomography (PET-CT) era.
  
  
  METHODS
  A retrospective review of 53 patients with proven sporadic MCT, who presented to our institution over a period 28 years from 1985 to 2012, was performed. Patients with persistently elevated levels of serum calcitonin (>150 pg/ml) were initially evaluated by a DMSA scan if conventional imaging failed to localize any focus of disease.
  
  
  CONCLUSIONS
  Our study showed that the postoperative levels of serum calcitonin significantly correlated with the overall survival of our patients and can possibly serve as a good prognostic marker. Tc-99m DMSA (V) scans demonstrated a sensitivity of 75%, specificity of 56%, a positive predictive value of 50%, and a negative predictive value of 80% in detecting metastasis in postoperative persistent hypercalcitoninemia. Our study showed that Tc-99m DMSA (V) scanning is an affordable and a reasonably sensitive imaging agent for localization of recurrent/metastatic disease. PET-CT seems to be a useful complementary tool and needs to be kept in the armamentarium for diagnosis of recurrence especially in cases of discordance between Tc-99m DMSA (V) scan and the serum calcitonin levels.
authors.affiliation: Department of Surgical Oncology, Cancer Institute (WIA), Adyar, Chennai, Tamil Nadu, India.
authors.forename: Arvind
authors.initials: A
authors.lastname: Krishnamurthy
authors.affiliation: Department of Nuclear Medicine, Cancer Institute (WIA), Adyar, Chennai, Tamil Nadu, India.
authors.forename: Ramachandran Krishna
authors.initials: RK
authors.lastname: Kumar
authors.affiliation: Department of Surgical Oncology, Cancer Institute (WIA), Adyar, Chennai, Tamil Nadu, India.
authors.forename: Praveen
authors.initials: P
authors.lastname: Ravishankaran
authors.affiliation: Department of Preventive Oncology, Cancer Institute (WIA), Adyar, Chennai, Tamil Nadu, India.
authors.forename: Vijayalaksmi
authors.initials: V
authors.lastname: Ramshankar
authors.affiliation: Department of Nuclear Medicine, Cancer Institute (WIA), Adyar, Chennai, Tamil Nadu, India.
authors.forename: Ahamed Sultan
authors.initials: AS
authors.lastname: Balkis Begum
authors.affiliation: Department of Preventive Oncology, Cancer Institute (WIA), Adyar, Chennai, Tamil Nadu, India.
authors.forename: Gomadam Kuppuswamy
authors.initials: GK
authors.lastname: Rangarajan
keywords: Medullary carcinoma thyroid; positron emission tomography-computerized tomography scan; serum calcitonin; technitium-99m dimercaptosuccinyl acid scan