Brain tumors represent a vexing clinical problem in oncology due to their increasing incidence, difficulties in treatment and high rates of recurrence. It is especially challenging to evaluate the posttreatment disease status because differentiation of recurrence from treatment-induced changes (radiation necrosis) is not possible with the use of magnetic resonance imaging, the most commonly used imaging method in this setting. Various functional imaging methods, including positron emission tomography and single photon emission computed tomography (SPECT) have been employed in this context. SPECT with 99m-technetium (99mTc)-glucoheptonate (GHA) has shown promising results for differentiation of recurrent brain tumor from radiation necrosis. In this review, we have discussed in details the basics of 99mTc-GHA SPECT imaging in brain tumor along with the available literature in this regard.

Spectrometer is used to perform various in vitro tests. The ability to successfully perform these tests depends on technologist's skill. Therefore, proper training of technologists is mandatory in gamma spectrometry. During the training, they need to have sufficient practice to gain sound theoretical and practical knowledge. High cost of spectrometer and risk of their damage during independent practice may hamper the process of proper training. Hence, there is a need of cheaper and more feasible option. Virtual spectrometer created in RADlab1.03 can address this issue. The immediate objective of this paper is to validate this virtual spectrometer so as to be used as an educational and research tool for trainees. Virtual spectrometer was calibrated using Cs-137 standard source and Cs-137 spectrum was recorded by positioning 28106 Bq Cs-137 source at 2.35 cm above top surface of the well, 1 cm above from the bottom of the well and at the bottom of the well. Ba-133 and Co-60 spectrum were also recorded. The experiments were repeated with real spectrometer for exactly the same conditions as applied to the virtual spectrometer. The paired t-test was applied to find the difference in mean photopeak at 5% level of significance. The sample data provided satisfactory evidence that mean photopeak obtained with real as well as virtual spectrometer were same at P value of 4.641 × 10⁻⁴ ,1.57 × 10⁻¹² ,1.40 × 10⁻²⁴ , 1.26 × 10⁻¹⁶ , and 8.7 × 10⁻⁹ for Cs-137 (photopeak: 664 keV, Co-60 (photopeak: 1181 keV), Co-60 (photopeak: Co-1348 keV), Ba-133 (photopeak: 304 keV) and Ba-133 (photopeak: 364 keV) respectively.

Context: F-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography/computed tomography (PET/CT) scan and hypothyroidism. Aims: The aim was to determine whether the intensity of diffuse thyroid gland uptake on F-18 FDG PET/CT scans predicts the severity of hypothyroidism. Materials and Methods: A retrospective analysis of 3868 patients who underwent F-18 FDG PET/CT scans, between October 2012 and June 2013 in our institution for various oncological indications was done. Out of them, 106 (2.7%) patients (79 females, 27 males) presented with bilateral diffuse thyroid gland uptake as an incidental finding. These patients were investigated retrospectively and various parameters such as age, sex, primary cancer site, maximal standardized uptake value (SUVmax), results of thyroid function tests (TFTs) and fine-needle aspiration cytology results were noted. The SUVmax values were correlated with serum thyroid stimulating hormone (S. TSH) levels using Pearson's correlation analysis. Statistical Analysis Used: Pearson's correlation analysis. Results: Clinical information and TFT (serum FT3, FT4 and TSH levels) results were available for 31 of the 106 patients (27 females, 4 males; mean age 51.5 years). Twenty-six out of 31 patients (84%) were having abnormal TFTs with abnormal TSH levels in 24/31 patients (mean S. TSH: 22.35 μIU/ml, median: 7.37 μIU/ml, range: 0.074-211 μIU/ml). Among 7 patients with normal TSH levels, 2 patients demonstrated low FT3 and FT4 levels. No significant correlation was found between maximum standardized uptake value and TSH levels (r = 0.115, P > 0.05). Conclusions: Incidentally detected diffuse thyroid gland uptake on F-18 FDG PET/CT scan was usually associated with hypothyroidism probably caused by autoimmune thyroiditis. Patients should be investigated promptly irrespective of the intensity of FDG uptake with TFTs to initiate replacement therapy and a USG examination to look for any suspicious nodules.

Introduction: Targeted therapeutic agents are indicated in metastatic lung cancers. These being receptor specific therapies, manifestation of response can be best assessed by estimating the metabolic activity of tumor, rather than the size. This retrospective analysis studied metabolic and morphological response on Positron Emission Tomography (PET) and Computed Tomography (CT), respectively to these agents. Materials and Methods: Thirty-one patients (23 males, 8 females with an age range of 42-77 years) with Epidermal Growth Factor Receptor (EGFR) positive metastatic lung cancer on Gefitinib, who underwent PET/CT, at baseline and at 4-6 weeks, were assessed by Response Evaluation Criteria In Solid Tumors [RECIST] 1.1 and European Organization for Research and Treatment of Cancer (EORTC) criteria. Results: Concordance between RECIST 1.1 and EORTC was seen in 26 (83.7%) patients. Discordance was seen in 5 (16.3%) patients. In patients with discordance, the results were confirmed by follow-up imaging. Metabolic EORTC criteria changed the disease status from stable disease to partial response (3 out of 5) and progressive disease (2 out of 5) in these five patients. Conclusions: Metabolic criteria using PET/CT could accurately predict response as well as disease progression early in the course of targeted therapy, compared to morphologic criteria. In addition, early metabolic response assessment can predict refractoriness of therapy.

Objectives: Renal cortical scintigraphy with technetium-99m (Tc-99m) dimercaptosuccinic acid (DMSA) is the method of choice to detect acute pyelonephritis and cortical scarring. Different acquisition methods have been used: Planar parallel-hole or pinhole collimation and single photon emission tomography (SPECT). This study compared planar parallel-hole cortical scintigraphy and dual-head SPECT for detection of cortical defects. Patients and Methods: We retrospectively reviewed 190 consecutive patients with 380 kidneys and 200 DMSA scans referred to rule out renal cortical scarring. The diagnoses were 52 vesicoureteric reflux, 61 recurrent urinary tract infection, 39 hydronephrosis, 20 renal impairment, and 18 hypertension. All patients were imaged 3 h after injection of Tc-99m DMSA with SPECT and planar imaging (posterior, anterior, left, and right posterior oblique views). For each patient, planar and SPECT images were evaluated at different sittings, in random order. Each kidney was divided into three cortical segments (upper, middle and lower) and was scored as normal or reduced uptake. The linear correlation coefficient for the number of abnormal segments detected between planner and SPECT techniques was calculated. Results: From 200 DMSA scans, 100 scans were positive for scar in SPECT images, from which only 95 scans were positive for scar in planner imaging. Out of the five mismatched scans, three scans were for patients with renal impairment and high background activity and two scans were for very small scars. No significant difference was seen in the average number of abnormal segments detected by planar versus SPECT imaging (P = 0.31). The average correlation coefficient between was high (r = 0.91 - 0.92). Conclusions: Tc-99m DMSA renal cortical scanning using SPECT offers no statistically significant diagnostic advantage over multiple views planar imaging for detection of cortical defect.

Generalized lymphadenopathy is a common and often vexing clinical problem caused by various inflammatory, infective and malignant diseases. We aimed to review briefly and highlight the potential role of ¹⁸ F-2-fluoro-2-deoxy-glucose ( ¹⁸ F-FDG) positron emission tomography/computed tomography (PET/CT) in such patients. ¹⁸ F-FDG PET/CT can play an important role in the management of generalized lymphadenopathy. It can help in making an etiological diagnosis; can detect extranodal sites of involvement and employed for monitoring response to therapy.

Extraskeletal osteosarcomas account for < 1% of the soft tissue sarcomas and are known to more often localize in soft tissues of the lower extremities. Primary osteosarcomas of the breast are extremely rare. A majority of the reported cases were in fact initially erroneously diagnosed and treated as primary breast carcinomas. We recently got to treat an interesting case of a primary breast osteosarcoma and discuss its evaluation and management with added emphasis on the incremental role of technetium 99-methylene diphosphonate (Tc-99m) bone scintigraphy in its clinical diagnosis. Tc-99m uptake can occasionally be seen in the delayed bone scintigraphy images of extra skeletal malignancies, but the uptakes are considered to be typically less intense than the uptakes noted in primary skeletal malignancies. Extraskeletal osteosarcomas are however the exceptions to this rule, the intense uptake in bone scintigraphy further aided in an accurate preoperative diagnosis and management of our patient.

Neuroendocrine tumor metastases to the liver can mimic primary hepatocellular carcinoma (HCC) on imaging, cytology, and core biopsy. We present a case study along with the literature review of a patient who presented as a solitary liver mass mimicking HCC and subsequently underwent a partial hepatectomy. The histopathology and immunohistochemisrty of the resected specimen revealed metastatic neuroendocrine carcinoma. Positron emission tomography (PET) scan with ⁶⁸ Ga-DOTA-NaI-octreotide ( ⁶⁸ Ga-DOTANOC) localized the primary tumor in the ileum. A curative follow-up surgery for resection of the small bowel containing the primary tumor was carried out. This case illustrates the shortcomings of routine imaging methods, utility of immunocytochemistry and the importance of ⁶⁸ Ga-DOTANOC PET in determining the metastatic spread as well as the origin of neuroendocrine tumors (NETs). This case report attempts to highlight the current imaging paradigms and management strategy of midgut and other NET's at the point of detection, staging and follow-up.

Pigmented villonodular synovitis (PVNS) is a rare, relatively benign, intra-articular lesion characterized by a slowly progressive proliferation of synovial tissue. Knee is the most frequently involved joint. Localized and diffuse forms of synovial involvement were reported. In extensive diffuse cases, total synovectomy is needed, almost impossible to achieve. Hence, other treatment modalities such as intra-articular injection of yttrium-90 have been tried and shown to be effective in reducing the rate of local recurrence with "acceptable" joint damage. Radiosynovectomy is based on the irradiation of the joint synovium by the intra-articular administration of various β-emitting radiopharmaceuticals. We describe the first case report of use of yttrium-90 hydroxyapatite particulates in a 33-year-old male who presented with diffuse PVNS of knee joint as a primary modality of treatment.

Cardiac angiosarcoma is the most common primary cardiac sarcoma in adults. Primary cardiac tumors are rare and have nonspecific clinical presentation, thus making its diagnosis challenging. Clinically, patients present with advanced disease demonstrating metastatic disease at initial presentation itself. It commonly metastasizes to lung, liver, brain, and bone; however metastases to lymph nodes, adrenal glands, spleen and skin has also been seen. We describe a case of right atrial angiosarcoma with extensive visceral metastases involving brain, lungs, liver, pancreas, kidney, and lymph nodes, demonstrated on contrast-enhanced ¹⁸ F-fluoro-deoxyglucose positron emission tomography-computed tomography (FDG PET-CT). To the best of our knowledge metastases to pancreas and kidney have not been reported so far in the literature. With our report, we emphasize on the initial use of FDG PET-CT in workup of cardiac angiosarcoma for accurate staging and prognostication of this disease.

Osteopetrosis is a rare inherited bone disease where bones harden and become abnormally dense. While the diagnosis is clinical, it also greatly relies on appearance of the skeleton radiographically. X-ray, radionuclide bone scintigraphy and magnetic resonance imaging have been reported to identify characteristics of osteopetrosis. We present an interesting case of a 59-year-old man with a history of bilateral hip fractures. He underwent ^99m Tc-methylene diphosphonate whole body scan supplemented with single-photon emission computed tomography/computed tomography of spine, which showed increased uptake in the humeri, tibiae and femora, which were in keeping with osteopetrosis.

Enteric duplication cysts (EDCs) are uncommon congenital anomalies, which can occur anywhere along the gastrointestinal tract and vary greatly in presentation, size, location and symptoms. Ectopic gastric mucosa is reported to be found in 20-30% of these duplications. ^99m Tc-pertechnetate scintigraphy is a useful modality for preoperative localization of the ectopic functioning gastric mucosa in the EDCs. We report a case where ^99m Tc-pertechnetate scintigraphy was useful in detecting synchronous thoracic and abdominal duplication cysts with functioning gastric mucosa thus having an impact on the patient management.

Primary pleural sarcomas constitute <1% of all primary lung cancers. Synovial sarcomas of the pleura are extremely rare. They may be mistaken for malignant mesothelioma or other spindle cell tumors, but the confirmation is by histology and immunohistochemistry. Synovial sarcomas are aggressive with a high incidence of recurrence. In this case report, we present the 18-fluoride-fluoro deoxyglucose (FDG) positron emission tomography-computerized tomography (PET-CT) findings of patient with primary pleural synovial cell sarcoma. The pretreatment and postchemotherapy FDG PET-CT scans are presented. The role of FDG PET-CT in initial staging and response assessment in this interesting case of pleural synovial sarcoma is presented.

Finding of focal 18F-fluoro-deoxyglucose (FDG) uptake in liver on FDG positron emission tomography/computed tomography (FDG PET/CT) in a known case of malignancy is often considered to be metastases. We report a similar finding on FDG PET/CT in a case of Ewing's sarcoma of thigh, which turned out to be of tuberculous etiology, an unusual cause of false positive FDG uptake in the liver.

Mucinous tubular and spindle cell carcinoma of the kidney (MTSCC-K) is an extremely rare carcinoma of the kidney, which develops by malignant differentiation of the collecting ducts or the loop of Henle. The tumor can occur at all ages, with 4 times higher prevalence in females than in males. A 62-year-old female patient presented with an asymptomatic mass lesion in the left kidney. The ultrasound revealed a hyperechogenic mass lesion measuring 4 cm in diameter and centrally located in the left kidney. Computed tomography (CT) revealed an isodense mass lesion measuring 4 cm in diameter and posterolaterally located in the left kidney. Magnetic resonance imaging revealed a renal mass of 4 cm in diameter with hypervascular contrast uptake. For primary staging, ¹⁸ F-fluorodeoxyglucose-positron-emission tomography ( ¹⁸ FDG-PET)/CT revealed left renal cell carcinoma (RCC) with a maximum standard uptake value of 6.7. The patient underwent transperitoneal radical nephrectomy. The immunohistochemical examination revealed MTSCC-K. ¹⁸ FDG-PET/CT provides 81-89% sensitivity and 83-100% specificity in primary staging of the renal cancers, in diagnosing metastatic RCC, and monitoring the response to therapy. Its use in the staging of MTSCC of the kidney has not been previously described in the literature. This case highlights the usefulness of ¹⁸ FDG-PET/CT in the staging of this rare tumor.

Immunoglobulin G4 (IgG4)-related disease encompasses a wide variety of immune disorders previously thought be distinct. IgG4-related retroperitoneal fibrosis is one such entity. Metabolic imaging with ¹⁸ F-fluorodeoxyglucose ( ¹⁸ F-FDG) positron emission tomography/computed tomography (PET/CT) can be useful in the management of IgG4-related retroperitoneal fibrosis. We here discuss the case of 63-year-old male with IgG4-related retroperitoneal fibrosis and the role, ¹⁸ F-FDG PET/CT played in his management.

Intramuscular myxoma (IM) is a rare benign neoplasm. In a patient diagnosed with IM of left thigh, we report the utility of a postoperative fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography scan in assessing the efficacy of surgical excision.

Radionuclide bone imaging is one of the most commonly performed nuclear medicine procedure around the world and characterized by its high sensitivity and relatively low specificity. False positive findings on a bone scan are very common; however, dense uptake over unilateral ossified anterior longitudinal ligament appearing as single thyroid lobe on a bone scan has not been described in the literature.

^99m Technetium-methylene diphosphonate bone scintigraphy (BS) has an important role in evaluating skeletal pathology, especially its extent. Incidental extra-osseous uptake may sometimes be seen in soft-tissue pathologies. We present a 64-year-old female with skull base osteomyelitis referred for BS which revealed involvement of the skull base on the left side, uptake was also noted in bilateral lungs secondary to hypercalcemia of renal failure and in the D12-L1 vertebrae as the patient had a history of Pott's spine. This is perhaps a unique case showing three findings each of a different etiology in the same scan.

A 48-year-old male patient with purely myxoid liposarcoma was referred to fludeoxyglucose positron emission tomography/computerized tomography (FDG PET/CT) for restaging. FDG PET/CT images showed a hypodense well-defined intermuscular mass with mild FDG uptake in the right gluteal region. In addition, multiple mild hypermetabolic masses that had similar characteristics with the aforementioned lesion were also revealed in the mesenteric region of abdomen and pelvis.

Gliomatosis cerebri (GC) is a rare condition in which an infiltrative glial neoplasm spreads through the brain with preservation of the underlying structure. F-18 fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) has an important role in demonstrating the appropriate metabolism and differentiating pathologies mimicking GC on CT and magnetic resonance imaging. We describe imaging findings of FDG PET/CT in GC in a 9-year-old male child mimicking encephalitis.

Urinary bladder diverticular carcinomas are uncommon with a lesser incidence of 0.8-10% and its diagnosis still remains a challenge. Cystoscopy is the most reliable method, but evaluating diverticulum with narrow orifices is difficult. Before the initiation of appropriate treatment, proper detection of bladder diverticular carcinoma and its locoregional and distant sites of involvement is necessary. Here, we present a case of 48-year-old male with urinary bladder diverticular carcinoma detected by forced diuretic ¹⁸ F-fluorodeoxyglucose positron emission tomography/computerized tomography ( ¹⁸ F-FDG PET/CT). This case also highlights the significance of forced diuretic ¹⁸ F-FDG PET/CT in the detection, staging, and response evaluation of bladder diverticular carcinoma.