Background: Osteoid osteoma is a benign bone tumor; diagnosed using x-ray and Computer Tomography (CT). It shows a nidus and cortical thickening. When the nidus is not well visualised especially in uncommon locations; Bone Scan (BS) can be performed for evaluation of osteoid osteoma.Methods: A retrospective observational study was done where 21 subjects presenting with suspicion of osteoid osteoma underwent BS using 10-20mCi (370 to 740MBq) of Technetium-99m Pertechnetate with perfusion, delayed cortical and Single Photon Emission Tomography/Computer Tomography (SPECT/CT). Increased perfusion and delayed focal cortical uptake was assessed on BS to locate osteoid osteoma. Response evaluation to Radiofrequency ablation (RFA) was also performed using BS.Results: Osteoid osteoma was detected in femur (8), spine (3), forearm bones (2), humerus (2), tibia (2), fibula in one and iliac bone in one patient using BS. BS detected more lesions (18) than CT scan where nidus as confirmatory sign was seen in 13 lesions. The McNemar test showed no significant difference (p=0.22) in the detection of osteoid osteoma using CT and BS in common location of femur. However there was significant difference noted between BS and CT in uncommon site (p=0.023). 3/8 patients showed persistent increased cortical activity after RFA ablation on BS.Conclusions: BS was more useful for confirmation of diagnosis of Osteoid osteoma for lesions in uncommon sites. BS also helped to assess response to RFA ablation therapy. SPECT/CT improved interpretation of BS to locate the osteoid osteoma.

Imaging of dextrocardia in humans requires an understanding of the orientation of the heart chambers and walls. There are many types of cardiac malpositioning, such as dextrocardia (with or without situs inversus), mesocardia, and levocardia. Myocardial perfusion scintigraphy of dextrocardia has been explained in case reports and imaging atlases; however, myocardial viability assessment using nuclear medicine imaging techniques is less documented in the literature. Methods: In 2 cases of dextrocardia with situs inversus and 1 case of mesocardia, myocardial viability was assessed using 99m Tc-sestamibi rest perfusion scintigraphy and 18 F-FDG PET. Cardiac SPECT images of dextrocardia with situs inversus were acquired using the feet-first supine position with a 180°arc from left anterior oblique to right posterior oblique, whereas a rightlateral-to-left-lateral arc was used for mesocardia. The processing and reconstruction were done by entering the dataset for the feetfirst supine position and repeating after entering the dataset for the feet-first prone position. The 2 sets of reconstructed images were compared for orientation of walls and cardiac chambers. Results: The first processing, using the feet-first supine position, revealed an interchanged septum and lateral wall in reconstructed images of dextrocardia with situs inversus. This interchange was corrected by changing the position to prone during processing of the rest perfusion and PET raw data. The display of cardiac slices in various axes matched the conventional nomenclature for the septum and lateral wall, leading to easy interpretation. However, this change was not required in the mesocardia, for which the location of the heart chambers was not interchanged. Conclusion: Because the acquisition protocol for SPECT is a semicircular orbit, the various types of dextrocardia require careful selection of the arc, with the patient positioning kept feet-first supine. Processing and reconstruction of data by changing the patient position to prone was found to be most useful method of matching the septum and lateral wall orientation for interpretation of images.

Context:The differential cortical function obtained by Tc-99m EC is comparable to that of Tc-99m DMSA. However, identification of scars on Tc-99m EC images needs to be studied.Aims:The aim of the study is to evaluate role of Tc-99m EC for detection of scarring and differential cortical function by comparing with Tc-99m DMSA.Settings and Design:Prospective observational study of recurrent UTI; minimum 6 weeks after acute episode; when urine examination is negative for pus cells.Materials and Methods:Forty-seven children with normal positioned kidneys underwent Tc-99m EC and DMSA scintigraphy. The DRF and cortical phase images of both studies in the same image matrix size were evaluated by two independent observers for scarring; Tc-99m DMSA was considered as the gold standard.Statistical analysis used:MS Excel 2007 and GraphPad Instat V3.1 and ROC analysis.Results:There was no significant difference in the detection of scarring using two studies with Cohen's kappa coefficient (κ) 0.932. The sensitivity and specificity of Tc-99m EC for detection of scarring was 98.75% and 99.15%, respectively. There was good agreement between the differential cortical function calculated using two studies.Conclusions:The summed Tc-99m EC images with an acceptable high image contrast allow detection of cortical scarring in patients with normal kidney positions. It is an excellent single-modality comprehensive investigational agent for renal parenchymal defects, function, and excretion evaluation with the added advantages of lower cost, convenience, and low radiation exposure to the child.

INTRODUCTIONGastric emptying time ½ (GET ½) is considered as the half time taken for chyme to pass into the duodenum. Gastric emptying depends upon numerous factors, both endogenous and exogenous. Nerve and hormones along with volume of meal, pH, particle size, composition and viscosity play part in gastric emptying.1 In infant population, gastric emptying also depends upon the maturity at the time of birth. The gastric emptying pattern is different in infants fed with breast milk and formula feeds and so gastric emptying has to be diligently worked out. 2There have been many studies performed using different radiopharmaceutical meals such as In-111 micro colloid in fixed quantity of milk, Tc-99m sulfur colloid in dextrose, Tc-99m labeled to chicken liver with establishment of various reference standards for liquid and solid emptying times. These studies have included age group varying from infancy till early childhood and age-related dependence was reported.3-8 The GET ½ or ABSTRACT Background: Gastric emptying time ½ (GET ½) is considered as the half time taken for chyme to pass into the duodenum. Gastric emptying depends upon numerous factors, both endogenous and exogenous. Nerve and hormones along with volume of meal, pH, particle size, composition and viscosity play part in gastric emptying. Aim of the study was to determine liquid gastric emptying Time ½ in infants and to evaluate impact of positive GER on Gastric Emptying Time. Methods: Total 149 full term babies from 29th day to 1 year of age; underwent Tc-99m labeled with Sulfur colloid GER scintigraphy using age specific formula. Babies with gastro-intestinal anomalies, lactose intolerance and low birth weight babies were excluded. The reference range of GET ½ was estimated from GER negative group and the same was compared with GER positive group. Results: Out of 149 babies 96 (64%) babies were GER positive and 53 (36%) were negative for GER. The liquid GET ½ values generated for 29 th day-3 months, 4-6 months, 7-9 months and 10 months -1year were 62.67 (12.42), 69.84 (13), 63.5 (9.7) and 53.2 (10) minutes respectively. The liquid GET½ was found to be delayed in severe GER positive group. Conclusions: The reference range for liquid GET½ was estimated from GER negative group utilizing the exclusion criteria thereby avoiding radiation exposure to normal controls. With increasing severity of GER there was consequent prolongation of liquid GET½.

Background: The ectopic thyroid tissue in thyroglossal cyst or suprahyoid swelling is one of most important differential to be diagnosed. The purpose of this study was to find out role of Technetium-99m Pertechnetate Thyroid Scintigraphy (TS) to detect functioning thyroid tissue in ectopic locations presenting as midline neck swelling.Methods: A retrospective observational study was done where 26 subjects presenting with midline neck swelling were included. These subjects were injected with 1-5MBq/kg of Technetium-99m Pertechnetate to perform the TS. The uptake of tracer in the midline neck swelling and in other ectopic location was assessed. The comparison with Ultrasound (USG) was also done.Results: 12 (46.15%) subjects presented with infra hyoid swelling and rest 14 (53.85%) presented with supra hyoid and submental swelling. 33.3% subjects presenting with thyroglossal duct cyst showed functioning thyroid tissue. Also 4 subjects showed dual functioning ectopic tissue. USG an TS showed concordant results for detecting thyroid tissue in ectopic location (p=0.68). However, TS performed better to detect ectopically located thyroid tissue (p=0.0086).Conclusions: USG and TS showed similar results to detect thyroid tissue in normal location. However, TS is better to detect topically located thyroid tissue. TS adds information of functioning thyroid tissue during workup of midline neck swelling.