Aim: 18F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG-PET/CT) is useful in the evaluation of lung cancer (LC), both for staging and therapy assessment. However, for the evaluation of treatment response, shared criteria are not available. We proposed a 3-point score, similar to Deauville-score and compared its diagnostic accuracy with Hopkins criteria for the evaluation of treatment response in LC to validate a qualitative and simpler interpretation system. Methods: We retrospectively included 93 patients with advanced stage (III-IV) LC who underwent ¹⁸F-FDG-PET/CT after first-line treatment. Positron emission tomography/computed tomography (PET/CT) scans were interpreted according to a 3-point scale-like Deauville score criteria (score 1 = uptake lower than blood-pool activity; score 2 = uptake higher than blood-pool but lower than liver activity; score 3 = uptake higher than liver). Inter-reader variability was assessed using percent agreement and kappa statistics. Kaplan–Meier plots with a Mantel-Cox log-rank test were performed, considering death as the endpoint. Results: The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of like Deauville-like score criteria were 82,76% (95% confidence interval [CI] 70.5%–91.4%), 80% (95% CI 28.3%–99%), 97.9% (95% CI 89.2%–99.6%), 28.6%(95% CI 16.38%–44.9%), and 82.5% (95% CI 70.9–90.9%), respectively. Applying Hopkins criteria score we obtained sensitivity, specificity, PPV, NPV, and accuracy of 81% [95% CI 68.6%–90.1%), 100% (95% CI 47.2–100%), 100% (95% CI %), 31.3% (95% CI 21.0%–43%), and 82.5%(95% CI 70.9%–90.9%), respectively. There was a high agreement between the two readers both using Hopkins criteria (k = 0.912) and like-Deauville-score criteria (k = 0.956). Applying 3-point-scale criteria, patients with positive PET/CT after therapy had significantly shorter lower survival (P = 0.0021). Conclusion: The application of 3-point scale criteria for posttherapy assessment in patients with advanced stage of LC represents an easy and reproducible method with optimal inter-observer agreement and great PPV and accuracy.

Purpose: Anaplastic thyroid carcinoma (ATC) is the most aggressive thyroid cancer and there is no established treatment that works well. The study was conducted to see prostate-specific membrane antigen (PSMA) expression in ATC as a stepping stone to study its role in potential theranostics. Materials and Methods: Pathologically proven ATC patients were prospectively included in this study. Ga-68-PSMA positron emission tomography/computed tomography (PET/CT) was done to look for PSMA expression in local and distant sites 45-60 mins after injecting 2-3mCi of tracer. Results: Twenty patients were enrolled in this study. Nodal metastases were seen in all patients, while distant metastases were seen in 17/20. The mean SUV_max of primary lesion was 6.72 ± 4.6. Mean SUVmax of node and lung lesions was 5.7 ± 5.6 and 2.9 ± 1.98, respectively. Mean SUV_max of liver, mediastinum, and parotid gland was 5.95 ± 3.03, 1.54 ± 0.68, and 9.03 ± 3.75, respectively. Mean Tumor to background ratio (liver = TBRl; mediastinum = TBRm; parotid = TBRp) were 1.21, 4.49 and 0.78, respectively. Conclusion: ATC showed variable PSMA expression on Ga-68-PSMA-PET/CT and this attribute may be potentially useful in ATC theranostics.

Aims and Objective: The aims and objective of this study to share the 15 years of working experience regarding importance of cartridges and resins used in a Purification Column during 18F-FDG synthesis. Materials and Methods: 18F- flourodeoxyglucose (18F-FDG) is common radiotracer used in positron emission tomography (PET). 18F-FDG is synthesized in a PET radiochemistry synthesis module and purification column is an integral part of 18F-FDG synthesis. The purification column has four integral parts, namely of ion exchange retardation resin, cation exchange resin, C18 bonded silica, Neutral Alumina. Conclusion: The purification column plays a very important role during the synthesis of 18F-FDG. If all parts of the purification column are intact, then maximum transfer of produced 18F-FDG from reaction vessels to the final product vial takes place. The total yield of 18F-FDG is also dependent upon the purification column. If all components of purification column placed tightly and properly charged then there is a high possibility of maximum yield of final product without impurities.

Purpose of the Study: The purpose of the study is to evaluate ^99mTc-labeled ethambutol (^99mTc-EMB) as a potential diagnostic agent in lymph node tuberculosis (LNTB). Materials and Methods: A prospective pilot study was done at All India Institute of Medical Sciences, New Delhi. We included adult consenting patients who were diagnosed with LNTB and were either treatment naïve or had just started treatment. Patients were injected with 10–15 mCi of ^99mTc-EMB. Whole-body anteroposterior planar imaging was done from 15 min after injection at serial intervals till 4–6 h along with one single-photon emission computed tomography–computed tomography (SPECT-CT) imaging with the help of a dual-head SPECT-CT gamma camera. The uptake of ^99mTc-EMB was analyzed and corroborated with clinicoradiological findings. Results: Between January 2019 and November 2020, we recruited 23 patients who underwent ^99mTc-EMB, and 19 scans were interpretable and considered for analysis. Cervical lymphadenopathy was the most common presentation (13, 68.42%), followed by mediastinal (9, 47.36%) and abdominal (4, 21.05%) nodes. Other involvement included pulmonary (8, 42.1%), gastrointestinal (3, 15.78%), and chest wall abscess and bone marrow deposits in 1 patient each. A positive scan was noted in 7 (53.84%) patients with cervical lymphadenopathy, whereas uptake in abdominal and mediastinal lymph nodes was seen in 1 (25%) and 2 (22.22%) cases, respectively. Uptake in pulmonary lesions was noted in 3 (37.5%), but uptake in hepatic and splenic lesions was not seen. Conclusion: ^99mTc-EMB scan can demonstrate drug penetrance in vivo in some patients with LNTB and should be explored further with a larger sample size.

Purpose of the Study: Renal mass lesions in majority of the cases are due to malignant etiology and about one-third of them are reported with metastatic lesions at the time of presentation. Thus proper investigational workup is needed for staging and thereby treatment planning. The current fluorine18 fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (F18-FDG PET/CT) study was designed to characterize renal mass lesions metabolically and identifying other metabolically active lesions in the body suggesting metastatic disease. Materials and Methods: A total of 24 patients (males – 18 and females – 6) with a mean age of 53.8 ± 12.3 years were recruited in this study for dual time-point PET/CT scan. All patients with renal mass lesions underwent contrast-enhanced CT prior to PET/CT. Metabolic parameters such as maximum standardized uptake value (max.SUV) with a cut off ≥2.5 and retention index (RI) of ≥10% were used to label the lesion as malignant and remaining less than cutoff as benign. The final diagnosis of lesion on imaging was confirmed with a histopathological examination (HPE). Results: Using max.SUV cut off value, 17/24 renal mass lesions were characterized as malignant and remaining 7/24 renal lesions of benign etiology. PET/CT showed sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 80%, 75%, 94.1%, 42.8%, and 79.1%, respectively, by considering HPE as a gold standard. Nine patients were diagnosed with distant site involvement suggestive of metastases. Conclusion: F18-FDG PET/CT can efficiently characterize solid renal mass lesion as benign and malignant using metabolic parameters such as max.SUV and RI. In addition, whole-body survey identified distant site involvement in 25% of the patients, thus contributing change in management.

Aims and Objectives: The objective of this study was to find the optimum value of threshold for compression of ^99mTc-methylene diphosphonate (MDP) bone scan images using discrete cosine transformation (DCT). Materials and Methods: DCT was applied to 51 ^99mTc-MDP bone scan images and then the image of logarithmic value of DCT coefficients was inspected to determine the threshold. After inspecting the number of images of DCT coefficients, we estimated the appropriate value of the threshold to be 10. After the application of threshold = 10, compressed image was reconstructed by applying the inverse DCT. Compression factor was calculated by dividing the nonzero element after thresholding to the nonzero element before thresholding DCT coefficients. Nuclear medicine physicians compared the compressed images with its input images and labeled them as acceptable or unacceptable. During comparison of input and compressed images, we considered points such as smoothening, blocking artifacts, body contour, gap between closely placed lesions, and detectability of lesion. Results: Forty-four compressed images (out of 51 images) obtained at threshold 10 were acceptable to Nuclear Medicine Physician (NMP). Compressed images were less noisy compared to its input image. Compression factor was found to be 13.03 ± (minimum = 2.71, maximum = 42.92). Conclusion: The optimum value of threshold for compression of ^99mTc-MDP bone scan images was found to be 10, and the average compression factor achieved was equal to 13.03 (92.30%).

Aims and Objective: The objective of this study was to evaluate the compression of renal dynamic (RD) study images using singular value decomposition (SVD) technique. Materials and Methods: 4600 images of fifty RD study were compressed by using SVD technique. Two Nuclear Medicine (NM) Physicians compared compressed images with their corresponding input images and labeled these as acceptable or unacceptable. The SVD computation time and compression ratio were calculated for each image. The quality of compressed image was also assessed objectively using the following image quality metrics: Error, structural similarity (SSIM), Brightness, global contrast factor, contrast per pixel (CPP), and blur. The error in split function (i.e., the error between split function calculated from compressed image and split function calculated from original image) was computed for every RD study. Wilcoxon signed-rank test with continuity correction was applied to find a statistically significant difference in ROI counts on compressed and original image at. Results: As per NM physicians compressed image frames look identical to the original image frames. Objectively the compressed images were brighter, less noisy, and also have better CPP. Based on the visual assessment, time activity curve generated from original and compressed image frames was identical. There was insignificant difference of ROI counts between the input and compressed image frames of 99m-Tc LLEC RD Study. There was no significant difference between the split renal function estimated from original and its compressed RD study. The average SSIM value, average compression ratio, and SVD computation time were found to be 0.7521, 1.475, and 0.1200. Conclusions: Visually, compressed image was identical to the original image. The percentage compression achieved was found to be up to 58% (compression factor achieved = 1.57). The SVD computation time was approximately 0.12 s for 64 × 64 matrix size image frame.

Background and Purpose: Paragangliomas (PGLs) are rare neuroendocrine tumors with imaging features that can overlap with other entities. This study hypothesizes that given overexpression of somatostatin receptor (SSTR) 2, PGLs can be differentiated on Ga-68 DOTATATE positron emission tomography/computed tomography (PET/CT) from other benign or malignant lesions. Materials and Methods: Ninety-six patients with known tumors of the head and neck who underwent Ga-68 DOTATATE PET/CT from May 2017 to December 2021 were retrospectively reviewed from a single institution. Of these, 43 patients had histopathological confirmation and 66 positive lesions were discovered on PET/CT. For each lesion, the SUV max, the SUV lesion to liver ratio, and the SUV lesion to spleen ratio were analyzed. Results: PGLs (n = 37) showed the most intense uptake, and the mean of SUVmax was 69.3 (range 3.7–225.9). Metastatic PGL and metastasis from other neuroendocrine tumors (n = 13) demonstrated intermediate uptake, the mean of SUVmax was 15.16 (range 2.3–40.3). Meningiomas (n = 3) had intermediate uptake, and the mean of SUVmax was 12.37 (range 2.5–19.4). One patient with esthesioneuroblastoma had 5 lesions in the head and neck, and the mean of SUVmax was 18.9 (range 6.9–49.4). Schwannomas (n = 4) had very low uptake, and the mean of SUVmax was 1.75 (range 1.1–2.2). Other rare cases with low uptake included 1 each of osteosarcoma, acinic cell carcinoma, ectopic thyroid tissue, and plasmacytoma, and the mean of SUVmax was 4.75 (range 2.3–6.1). Conclusions: Ga-68 DOTATATE PET/CT can be a useful adjunct in differentiating tumors in the head and neck. PGLs demonstrate the highest uptake. Meningioma, esthesioneuroblastoma, and neuroendocrine tumor metastasis have intermediate uptake. Schwannomas and other rare tumors exhibit low uptake.

Background: Diabetes mellitus is a common lifestyle disease where patients suffer from gastric dysmotility, which is usually underdiagnosed. The aim of this study was to evaluate the utility of Tc-99m sulfur colloid-labeled meal gastric emptying scintigraphy in Type 2 diabetic patients. Methods: A total of 43 patients and 30 controls, satisfying the inclusion criteria from March 2019 to August 2020, were included. Serial planar images were acquired in both anterior and posterior projections for an iso-time of 1 min at 1 min, 60 min (1 h), 120 min (2 h), and 240 min (4 h) after consumption of Tc-99m SC-labeled idly (rice cakes). The gastric emptying was considered delayed if there was <10% emptying at 1 h, <70% emptying at 2 h, and <94% emptying at 4 h. Results: The mean T1/2 was similar among cases (44.11 ± 10.52 min) and controls (49.56 ± 13.44 min, P = 0.056) while the mean gastric emptying at 1 h was slower in cases compared to controls, P = < 0.01. Two cases (4.6%) had delayed gastric emptying while none of the controls had delayed gastric emptying. T1/2 showed no association with duration of diabetes or HbA1c levels (P = 0.76, 0.45) and a weak correlation with fasting blood sugar (FBS) on the day of scan (R value = 0.18). Conclusion: In comparison to controls, diabetic patients had faster gastric emptying with no association with duration of diabetes or HbA1c levels and a weak correlation with FBS on the day of scan.

Acquired tracheobronchial fistulas are a relatively uncommon complication. Among them, tracheo-mediastinal-parenchymal fistulas are particularly rare. Most of the reported cases are associated with concurrent chemoradiotherapy in lung cancer. It has not been reported in lymphomas. These fistulas are associated with high mortality due to infection and bleeding, and there is no consensus on a definitive optimal therapy. Here, we present a case of tracheoparenchymal fistula in a follow-up primary mediastinal B-cell lymphoma case. This case highlights the utility of fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) in the initial diagnosis and follow-up of lymphoma. The PET/CT could show demonstrate the residual disease and differentiate it from other therapy-related benign changes.

High ¹⁸F-Fluorodeoxyglucose (¹⁸F-FDG) uptake in a cardiac mass is considered to be a marker of malignancy, but that is not always true. We here present such a case of incidentally detected ¹⁸F-FDG cardiac mass on staging positron emission tomography-computed tomography in a woman with head-and-neck cancer, confirmed to be myxoma on contrast-enhanced magnetic resonance imaging and subsequent histopathology.

Carcinoma cervix spread to locoregional lymph nodes. Distance metastases are uncommon and occur through hematogenous routes in advanced stages. The common sites include bone and lungs. Another organ involvement is uncommon. Computed tomography (CT) and magnetic resonance imaging have a crucial role in diagnosing local and distant metastasis. 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG PET/CT) is a sensitive molecular imaging modality for various cancers, including gynecological ones. We present a case of recurrent cervical carcinoma presented with cervical mass and several rare visceral metastases. 18F-FDG PET/CT is a whole-body modality that accurately localized all lesions in a single study.

A 61-year-old male underwent fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) for evaluation of fever and weight loss with clinical suspicion of occult malignancy or tuberculosis. The scan showed hypermetabolism in bilateral submandibular salivary glands, biliary radicles, pancreas, bilateral kidneys, prostate, and multiple lymph nodes. Based on the concomitant involvement of these sites, suspicion of immunoglobulin G4 (IgG4)-related disease was raised in PET-CT report. Further evaluation with serum IgG4 levels and histopathology of the submandibular salivary gland confirmed the diagnosis of IgG4-related disease. The ability of FDG PET-CT to evaluate the whole-body status of disease played a crucial role in this case.

Primary thyroid lymphoma (PTL) is an uncommon malignancy. The majority of PTLs are non-Hodgkin's lymphoma. Fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) is the state-of-the-art imaging in lymphoma and plays a pivotal role in staging, follow-up, and treatment decisions. There is good evidence that it performs well in a wide variety of nodal and extranodal lymphomas (ENL). However, the data are scarce on its usefulness in rare ENL. Herein, we describe four cases of PTLs and a brief review of the literature. FDG PET/CT was performed at baseline to assess the disease status and response to treatment. This case series highlights the varied appearance of PTL and response to treatment. It establishes the importance of FDG PET/CT in the personalized management of PTL.

We report a case of omicron infection in a biopsy-proven case of carcinoma breast sent for staging F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) during the omicron COVID wave. FDG PET/computed tomography (CT) revealed increased FDG uptake in nasopharyngeal, oropharynx, and tonsillar regions and bilateral cervical lymph nodes along with uptake in primary carcinoma and locoregional lymph nodes. Based on the clinical history and specific pattern of FDG PET/CT findings (as suggested by SNMMI Taskforce), COVID history and reverse transcription polymerase chain reaction positivity was elicited.

Adrenocortical carcinoma (ACC) is an uncommon and highly aggressive malignancy with a poor prognosis. Common sites of metastasis are lung, liver, and lymph nodes. We present a case of ACC in a 54-year-old female with an early disease recurrence of unusual hypervascular peritoneal metastatic abdominal-pelvic deposits detected on ¹⁸F-fluorodeoxyglucose positron emission tomography–contrast-enhanced computed tomography scan.

Ebstein's anomaly is a rare congenital heart disease. We present the case of a 47-year-old woman with history of Ebstein's anomaly who was referred to nuclear medicine department for a myocardial perfusion single-photon emission computed tomography (SPECT) imaging during pre-anesthetic check-up. Myocardial SPECT perfusion images with (99mTc)-Sestamibi demonstrated medium sizes fixed perfusion defect in the mid and proximal infero-septal wall adjacent inferior wall. This is a cause of potential misinterpretation on myocardial SPECT perfusion imaging as this perfusion defect was due to fibrosis rather than scarred myocardium.

Urothelial or transitional cell carcinoma is the most prevalent variant of urinary bladder carcinoma worldwide occurring in both men and women. There are a very few cases described in the literature with metastasis to skeletal muscles and even fewer cases with metastatic site in the brain. We present a case of high-grade urothelial carcinoma with metastasis to the left temporal lobe as well as multiple inter- and intra-muscular deposits in the left thigh.

Primary lung cancers in children are rare, and most children are diagnosed incidentally while being investigated for another medical problem. The diagnosis of primary lung tumors in children is very difficult because many children are asymptomatic until the advanced stages of the disease and nonspecific imaging findings. Although the usage of ⁶⁸Ga-tetraazacyclododecane tetraacetic acid-DPhe1-Tyr3-octreotate (⁶⁸Ga-DOTATATE) positron emission tomography/computed tomography (PET/CT) in adult patients is well known, it is a relatively new imaging modality for the pediatric patient group. Herein, we presented a unique case of large-cell neuroendocrine carcinoma of the lung in a child on ⁶⁸Ga-DOTATATE PET/CT.

A 60-year-old male, a diagnosed case of squamous cell carcinoma of the hypopharynx, underwent 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for response assessment. PET/CT revealed mildly increased 18F-FDG uptake and contrast enhancement in the region of the primary, which was suggestive of postradiation changes. Interestingly, a benign-looking cyst was seen in the shrunken, poorly-functioning left kidney, with mildly elevated 18F-FDG uptake. Structurally, the lesion appeared benign on ultrasound and sequential CT images. However, 18F-FDG was the only feature which alluded to the possibility of another pathology like low-grade malignancy or oncocytoma. The lesion was biopsied, which revealed Clear-Cell International Society of Urologic Pathologists grade-1 renal cell carcinoma. Consequently, the patient was posted for surgery.

Hepatic mass lesions and focal fat sparing in a fatty liver may be difficult to differentiate on contrast-enhanced computed tomography (CT) imaging and F-18-fluorodeoxyglucose positron emission tomography/CT. Tc-99m Sulfur colloid (SC) scintigraphy has been used in the assessment of solid hepatic masses. Liver metastases will appear as focal photopenic defects due to the loss of Kupffer cell function. However, focal fatty infiltration or fat sparing of the liver does not affect Kupffer cell function and thereby leading to normal tracer uptake. Despite several advances in imaging modalities, Tc-99m SC scintigraphy is still a reliable armamentarium in the characterization of hepatic mass lesions.

We report a case of a 66-year-old man with prostate cancer who underwent ¹⁸F-prostate-specific membrane antigen positron emission tomography/computed tomography for baseline staging that revealed primary lesion in prostate gland along with a solitary metastatic deposit in the penile shaft. Penile metastasis is rare and usually associated with widespread metastatic disease. Solitary penile metastasis is even rarer and can present as a unifocal, multifocal, or diffuse lesion. Early detection is important in guiding treatment and preventing complications.

A 13-year-old adolescent male presented with an episode of rectal bleed. He has had five such episodes in the past year where he witnessed black tarry stools mixed with fresh blood, painless, not associated with fever or hematemesis. Clinical examination revealed pallor and a soft, non-tender abdomen. Vitals were stable. Blood investigations revealed haemoglobin of 102g/L, WBC count of 10 X 109/L and platelet count of 165 x 109/L. The clotting screen was normal. Upper GI endoscopy and colonoscopy revealed no abnormality. The patient underwent Tc-99m pertechnetate scintigraphy to look for Meckel's Diverticulum in view of painless lower GI bleed.