Neuroendocrine tumors (NETs) are rare neoplasms characterized by overexpression of somatostatin receptors (SSTRs). Functional imaging plays a crucial role in management of NETs. Recently, positron emission tomography/computed tomography (PET/CT) with ⁶⁸Gallium (⁶⁸Ga)-labeled somatostatin analogues has shown excellent results for imaging of NETs and better results than conventional SSTR scintigraphy. In this review we have discussed the utility of ⁶⁸ Ga-labeled somatostatin analogue PET/CT in NETs for various established and potential indications. In addition we have also shared our own experience from a tertiary care center in India.

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Meckel's diverticulum (MD) is the most common gastrointestinal anomaly with heterotopic mucosa in 60% of cases. 99m technetium-pertechnetate scintigraphy is a sensitive tool for detection of MD containing heterotopic gastric mucosa. It is usually located in the right lower quadrant or umbilical region and less frequently in other quadrants. A mobile or wandering MD is a rare clinical presentation and may pose a diagnostic dilemma. However, presence of temporal correlation with gastric activity and compactness of focus during wandering period could make this riddle easy.

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Aim: The aim of this study is to evaluate the role of ⁶⁸ Ga-DOTATATE positron emission tomography/computed tomography (PET/CT) scan for the detection of bone metastases in pediatric neuroendocrine tumors (NETs) and to compare it with CT scan. Materials and Methods: A total of 30 patients (18 were males and 12 were females; age range: 1-18 years; mean age 7.6 years) with histologically confirmed NETs referred to our department were retrospectively analyzed. All patients underwent ⁶⁸ Ga-DOTATATE PET/CT scan at the time of diagnosis for primary staging. Contrast enhanced CT (CECT) performed at the time of PET scan acquisition was used for comparison with PET data. Imaging results were analyzed on a per-patient and on a per-lesion basis. Clinical follow-up of all patients and repeat PET/CT imaging ( n = 10) was taken as the reference standard. Results: Out of the 30 patients, 17 had no evidence of bone metastases on any imaging modality or on clinical follow-up while the rest of 13 patients showed evidence of bone metastases (nine showing positivity both on ⁶⁸ Ga-DOTATATE PET and CT scan while four showing positivity only on ⁶⁸ Ga-DOTATATE PET). Compared with CT scan, ⁶⁸ Ga-DOTATATE PET detected bone metastases at a significantly higher rate ( P = 0.0039). On a per lesion analysis, out of a total of 225 lesions detected by ⁶⁸ Ga-DOTATATE PET, only 84 lesions could be detected by CT scan. Conclusion: ⁶⁸ Ga-DOTATATE PET/CT scan is more useful than CECT scan for the early detection of bone metastases in pediatric NETs.

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Background: Lead-based shields are the standard method of intraoperative radiation protection in the radiology and nuclear medicine department. Human lead toxicity is well documented. The lead used is heavy, lacks durability, is difficult to launder, and its disposal is associated with environmental hazards. The aim of this study was to design a lead free paint for protection against X and gamma rays. Materials and Methods: In this pilot st we evaluated several types of nano metal powder that seemed to have good absorption. The Monte Carlo code, MCNP4C, was used to model the attenuation of X-ray photons in paints with different designs. Experimental measurements were carried out to assess the attenuation properties of each paint design. Results: Among the different nano metal powder, nano tungsten trioxide and nano tin dioxide were the two most appropriate candidates for making paint in diagnostic photon energy range. Nano tungsten trioxide (15%) and nano tin dioxide (85%) provided the best protection in both simulation and experiments. After this step, attempts were made to produce appropriate nano tungsten trioxide-nano tin dioxide paints. The density of this nano tungsten trioxide-nano tin dioxide paint was 4.2 g/cm ³ . The MCNP simulation and experimental measurements for HVL (Half-Value Layer) values of this shield at 100 kVp were 0.25 and 0.23 mm, respectively. Conclusions: The results showed the cost-effective lead-free paint can be a great power in absorbing the X-rays and gamma rays and it can be used instead of lead.

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Purpose: The purpose of this study is to evaluate the added value of single photon emission computed tomography-computed tomography (SPECT-CT) over planar scintigraphy, SPECT and CT alone for characterization of isolated skull lesions in bone scintigraphy (BS) in cancer patients. Materials and Methods: A total of 32 cancer patients (age: 39.5 ± 21.9; male: female - 1:1) with 36 isolated skull lesions on planar BS, underwent SPECT-CT of skull. Planar BS, SPECT, CT and SPECT-CT images were evaluated in separate sessions to minimize recall bias. A scoring scale of 1-5 was used, where 1 is definitely metastatic, 2 is probably metastatic, 3 is indeterminate, 4 is probably benign and 5 is definitely benign. With receiver operating characteristic analysis area under the curves (AUC) was calculated for each modality. For calculation of sensitivity, specificity and predictive values a Score ≤3 was taken as metastatic. Clinical/imaging follow-up and/or histopathology were taken as reference standard. Results: Of 36 skull lesions 11 lesions each were on frontal, parietal and occipital bone while three lesions were in the temporal bone. Of these 36 lesions, 16 were indeterminate (Score-3) on planar and SPECT, five on CT and none on SPECT-CT. The AUC was largest for SPECT-CT followed by CT, SPECT and planar scintigraphy, respectively. Planar scintigraphy was inferior to SPECT-CT ( P = 0.006) and CT ( P = 0.012) but not SPECT ( P = 0.975). SPECT was also inferior to SPECT-CT ( P = 0.007) and CT ( P = 0.015). Although no significant difference was found between SPECT-CT and CT ( P = 0.469), the former was more specific (100% vs. 94%). Conclusion: SPECT-CT is better than planar scintigraphy and SPECT alone for correctly characterizing isolated skull lesions on BS in cancer patients. It is more specific than CT, but provides no significant advantage over CT alone for this purpose.

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VACTERL is a cluster of congenital malformations based on the non-random association of various congenital malformations in a single patient. Here "V" denotes vertebral defects or vascular anomalies (single umbilical artery), "A" anal atresia, "C" cardiac abnormalities, "TE" tracheoesophageal fistula, "R"renal (kidney) abnormalities and "L" for limb anomalies) It is called an association, rather than a syndrome because the complications are not pathogenetically related, tend to occur more frequently than expected and are thought to be linked to embryonic mesodermal defects. Studies have reported the coexistence of various other congenital malformations such as respiratory, cerebral anomalies, which are frequently referred as non-VACTERL-type of associations. Diagnosis of VACTERL association is done only when at least three of the above mentioned congenital malformations are identified in a patient. Although 80% of these cases have vertebral defects, our case is unique as patient does not have one of the commonest occuring association i.e., vertebral anomalies, but has all other associations and an additional non VACTERL brain anomaly, hitherto unreported in the literature. The other highlight of this case is although reports say that VACTERL babies with ipsilateral renal disorder have the same side limb defects, our case has a renal anomaly with no limb anomaly. Finally VACTERL and non VACTERL association was considered in our patient in view of ventricular septal defect, tracheo esophageal fistula, anal atresia, renal anomaly, seizure disorder and global developmental delay due to pontocerebellar hypoplasia.

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Follow-up bone scintigraphy (BS) in a patient of carcinoma left breast, who was treated with surgery followed by radiotherapy 12 years back, revealed asymmetrically increased radiotracer uptake in left-sided ribs. Since, this pattern was atypical for metastatic rib involvement, single photon emission computed tomography/computed tomography (SPECT/CT) of thorax was done in the same setting which revealed circumferential nodular left-sided pleural thickening. Biopsy confirmed it to be pleural mesothelioma. Left-sided ribs showed no abnormality on CT, thus suggesting the rib uptake as reactive in nature. This pattern of asymmetric rib uptake on BS should be kept in mind and warrants further investigation for determining underlying pathology.

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False-positive findings are commonly seen in positron emission tomography computed tomography imaging. One of the most common false positive finding is uptake of fluorodeoxyglucose in brown adipose tissue. Herein, we report two cases with incidentally detected hibernomas-a brown fat containing tumor with metabolic activity.

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Patients with estrogen-receptor-positive advanced breast cancer are treated with endocrine therapy. The majority of breast cancer localizations show 18F-fluorodeoxyglucose (FDG) uptake at positron emission tomography (PET) examination. In these patients, the metabolic flare after therapy is common and was proposed as an index of therapy efficacy. Nevertheless, prolonged persistence of flare can lead to misinterpretation. We describe a case of a patient with invasive ductal breast cancer with bone metastases at bone scintigraphy and FDG PET scan and with expression of estrogen receptors. Initially, the patient underwent endocrine therapy in addition to a biphosfonate. Owing to progression observed in a bone scan, Tamoxifen was substituted with aromatase inhibitors. Successive bone scan examinations showed stabilization with a marked clinical improvement. A second FDG PET was performed 28 months after the first examination and showed a metabolic flare phenomenon with concomitant partial calcification of osteolitic lesions. This is an unusual case of prolonged metabolic flare.

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Cases of primary neuroendocrine carcinoma (NEC) of the breast have been reported, though rare. We report the case of a 45-year-old woman presented with jaundice and evaluated to have liver metastasis from neuroendocrine origin. She underwent whole body positron emission tomography/computed tomography, which showed left breast lesion and bone metastasis. Fine-needle aspiration (FNA) of breast revealed a NEC. A diagnosis of a primary NEC of the breast was rendered with hepatic and bone metastasis. She was treated with peptide receptor radionuclide therapy and is on follow-up.

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Leptomeningeal carcinomatosis is an infrequent disease and although its treatment is palliative, earlier diagnosis will lead to prolonged survival and improve functional outcome. Whole-body FDG-PET allows the entire spinal cord to be examined noninvasively, so close attention should be paid to the spinal canal, since these lesions can easily be mistaken for physiologic uptake, sometimes there is no clinical suspicion and may occur without concurrent active cancer. We present a female patient with a history of carcinoma of the breast, who presented an elevation of serum tumor marker CA 15-3. An FDG-PET/CT study only revealed multiple abnormal uptake at the vertebral foramen at thoracic and lumbosacral regions suggesting leptomeningeal metastases that were confirmed by MRI and cerebrospinal fluid cytology.

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We present here a case of primary non-Hodgkin's lymphoma of the breast that succumbed in a sub-acute course to death after three months of initial remission. The fluorodeoxyglucose positron emission tomography imaging during the declining clinical status showed isolated cerebellar hypermetabolism.

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Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) has revealed many unusual presentations and early detection of metastasis in many carcinomas. Epidural involvement in the spine is mostly sequelae of direct infiltration from bony involvement. Direct hematogenous spread to epidural space is very rare. Early diagnosis and treatment before the development of permanent neurologic and functional deficits is essential for a favorable prognosis in such cases. We report here a case of solitary spinal epidural metastasis from lung cancer which was the only systemic metastasis detected on F-18 FDG PET/CT and later confirmed by clinical and regional magnetic resonance imaging findings. This report is, to the best of our knowledge, the first description of such a presentation of systemic metastasis from lung cancer on F-18 FDG PET/CT.

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Bilateral trigeminal nerve involvement is a rare presentation of Non-Hodgkin lymphoma (NHL). The trigeminal nerve, also called the fifth cranial nerve, leaves the brainstem and exits the base of the skull to supply sensation to the face. In this case, we present a case of a 63-year-old male patient with a history of NHL and a more recent history of headache and trigeminal neuralgia. The patient underwent PET/CT demonstrating bilateral increased FDG uptake in trigeminal nerves.

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