Technical NEMA NU2-2018 Performance Assessment of Time-of-Flight-Integrated Digital PET-CT System.

Aim The objective of this study includes the NEMA (National Electrical Manufacturer Association) NU2-2018 performance evaluation of the uMIvista PET-CT (positron emission tomography-computed tomography) system. Methods The latest NEMA NU2-2018 guidelines have been followed for the evaluation of performance parameters of this PET-CT scanner: axial, tangential, and radial spatial resolution, sensitivity, counting losses, scatter, randomness, random and counting loss correction, image quality, time and energy resolution, image uniformity, and image registration alignment post installation of country first uMIvista PET-CT. Results The measured NEMA sensitivity of the uMIvista PET scanner was 12.053 cps/kBq. The spatial resolutions of the PET were measured as tangential, radial, and transaxial spatial resolutions at 10 mm, with 3.01 mm, 2.95 mm, and 2.93 mm, respectively; at 100 mm, with 3.17 mm, 3.42 mm, and 3.05 mm, respectively; and at 200 mm, with 3.65 mm, 4.54 mm, and 3.17 mm, respectively, at full-width half-maximum (FWHM); while at full-width tenths-maximum (FWTM), the values at 10 mm were 5.79 mm, 5.57 mm, and 5.69 mm, respectively, and at 100 mm were 5.59 mm, 5.96 mm, and 5.91 mm, respectively. The measured time-of-flight (TOF) timing resolution was 302.294 ps and the measured energy resolution was 11.76% with FWHM and FWTM. Conclusion The NEMA NU2-2018 performances of this TOF-integrated digital PET-CT system are extremely good in all parameters.

Role of Various Metabolic Parameters Derived From Baseline 18F-FDG PET/CT as Prognostic Markers in Non-Small Cell Lung Cancer Patients Undergoing Platinum-Based Chemotherapy.

PURPOSE: The aim of this study was to prospectively evaluate the role of various quantitative and semiquantitative metabolic parameters derived from dynamic and static baseline F-FDG PET/CT in prediction of overall survival (OS) in non-small cell lung cancer (NSCLC) patients who were planned to undergo platinum-based chemotherapy. METHODS: Sixty patients (51 male and 9 female patients) with biopsy-proven NSCLC and mean age 59.55 ± 10.06 years who were planned to undergo platinum-based chemotherapy were enrolled in the study. Each patient underwent a baseline regional dynamic and a static whole-body F-FDG PET/CT after injecting 0.21 mCi/kg (5.18-7.77 MBq/kg) of F-FDG intravenously. Two dynamic PET/CT parameters, that is, net influx rate constant and glucose metabolic rate at 30 and 60 minutes, were evaluated. In addition, whole-body PET/CT parameters, that is, SUVmax, average SUV, tumor-to-background ratio, metabolic tumor volume (MTV), total lesion glycolysis (TLG) of the primary tumor, and MTV and TLG of whole-body tumor lesions, were evaluated. Best possible cutoffs for all parameters were calculated using receiver operating characteristic curve analysis. Survival analysis was performed using log-rank test, Kaplan-Meier curves, and Cox proportional hazards model to determine the prognostic markers for OS. RESULTS: The median follow-up period was 4.4 months (range, 8 days to 15.9 months). In univariate analysis, the 4 static whole-body PET/CT parameters, that is, MTV, TLG, and MTV and TLG of whole-body tumor lesions, were found to be significantly associated with OS with cutoff values of 120, 800, 160, and 1350 cm and hazard ratios of 3.64 (P = 0.001), 3.35 (P = 0.002), 2.51 (P = 0.019), and 2.69 (P = 0.008), respectively. In multivariate survival analysis, MTV was found to be an independent prognostic marker for OS. CONCLUSIONS: Baseline MTV and TLG evaluated from primary tumor as well as the whole-body tumor lesions are reliable prognostic markers of OS in NSCLC patients undergoing platinum-based chemotherapy. However, other baseline whole-body PET/CT parameters (SUVmax, average SUV, and tumor-to-background ratio) and dynamic PET/CT parameters (net influx rate constant, glucose metabolic rate) have no prognostic value in these patients.

18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography in Tuberculosis: Spectrum of Manifestations.

The objective of this article is to provide an illustrative tutorial highlighting the utility of 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG-PET/CT) imaging to detect spectrum of manifestations in patients with tuberculosis (TB). FDG-PET/CT is a powerful tool for early diagnosis, measuring the extent of disease (staging), and consequently for evaluation of response to therapy in patients with TB.

Differentiation of Malignant Thrombus From Bland Thrombus of the Portal Vein in Patient With Hepatocellular Carcinoma on 18F-FDG PET CT.

Hepatocellular carcinoma carries a high risk of invasion of the portal vein. Neoplastic and bland portal vein thrombi discrimination is of great clinical significance for determining the therapeutic approach, predicting survival, and assessing candidates for liver transplantation. F-FDG PET/CT may be helpful in discriminating between malignant and portal vein thrombi. We present the case of a 61-year old man who presented with hepatocellular carcinoma with portal vein involvement. F-FDG PET/CT has a role in differentiating malignant from benign portal vein thrombosis.

Pleuroperitoneal Mesothelioma: A Rare Entity on 18F-FDG PET/CT.

Pleuroperitoneal mesothelioma is an extremely rare entity. Only few cases are reported worldwide. We hereby represent a case of pleural mesothelioma referred for F-18-Fluorodeoxyglucose positron emission tomography/computed tomography for response evaluation. Diffuse F-18-Fluorodeoxyglucose avid peritoneal and omental thickening noted which subsequently turned out to be mesothelial involvement on peritoneal biopsy. This case demonstrates the role of F-18-Fluorodeoxyglucose positron emission tomography/computed tomography in detecting other sites of involvement in case of malignant mesothelioma.

FDG PET/CT in Carcinoma of the Tongue With Bilateral Adrenal Metastases.

Squamous cell carcinoma is the most common malignant neoplasm of the oral cavity, and it contributes approximately 90% of all oral malignancies. We present a case of a squamous cell carcinoma of the tongue with rare site of bilateral adrenal metastases on F-FDG PET/CT with response evaluation after chemotherapy.

Incremental value of single-photon emission computed tomography/computed tomography in the diagnosis of active condylar hyperplasia.

OBJECTIVE: To evaluate the incremental value of technetium-99m methylene diphosphonate (Tc-MDP) single-photon emission computed tomography/computed tomography (SPECT/CT) over planar bone scintigraphy (BS) and SPECT for the diagnosis of active condylar hyperplasia (CH). PATIENTS AND METHODS: Data of 21 patients (mean age: 21.9±5.3 years, 10 males, 11 females) who underwent Tc-MDP BS along with regional SPECT/CT for the diagnosis of active CH were retrospectively evaluated. Planar BS, SPECT, and SPECT/CT images were evaluated by two nuclear medicine physician in consensus. Radioactive counts were measured per region of interest and the respective ratios were calculated. A percentage of condylar uptake 55% or higher, generating differences of 10% or more between condyles, was considered to be indicative of active unilateral condylar hyperactivity. Sensitivity, specificity, and positive and negative predictive values were calculated separately for planar BS, SPECT, and SPECT/CT. Clinical/imaging follow-up and histopathology was considered the reference standard. RESULTS: Planar BS, SPECT, and SPECT-CT of 21 patients with suspected CH were retrospectively evaluated. Planar BS was positive in eight patients, of whom six had active CH as the final diagnosis. SPECT was positive in 14 patients, of whom 12 patients had CH. Out of 14 patients who were positive in SPECT, two patients were considered negative in SPECT-CT. The diagnostic accuracy was the lowest for planar BS (47.6%) and the highest for SPECT/CT (85.8%). SPECT/CT and SPECT had similar sensitivity (80%), whereas SPECT-CT had the highest specificity (100%). CONCLUSION: SPECT/CT is superior to planar BS and SPECT for the diagnosis of active CH.

FDG DOTANOC Mismatch in In Vivo Characterization and Grading of Neuroendocrine Tumor.

Neuroendocrine tumors (NETs) are rare heterogeneous neoplasm of variable aggressiveness. A 55-year-old woman underwent Ga-DOTANOC PET-CT for suspected NET, which revealed DOTANOC-avid soft tissue mass in the second part of the duodenum with multiple hepatic metastases. Another non-DOTANOC-avid abdominal mass and hypodense lesion in segment VI of the liver were noted. For further evaluation, FDG PET-CT was performed, which revealed increased uptake in the abdominal mass and lesion in segment VI of the liver. Biopsy from the previously mentioned lesions revealed poorly differentiated high-grade NET.

Primary pulmonary lymphoma-role of fluoro-deoxy-glucose positron emission tomography-computed tomography in the initial staging and evaluating response to treatment - case reports and review of literature.

Primary pulmonary lymphoma (PPL) is an uncommon entity of non-Hodgkin lymphoma, which accounts for <1% of all cases of lymphoma. We present two rare cases of PPL of diffuse large B-cell lymphoma, which underwent (18)fluorine fluoro-deoxy-glucose positron emission tomography-computed tomography for initial staging and response evaluation after chemotherapy.

99mTc-DMSA planar imaging versus dual-detector SPECT for the detection of renal cortical scars in patients with CKD-3.

OBJECTIVE: The aim of this study was to compare planar technetium-99m-dimercaptosuccinic acid (Tc-DMSA) cortical scintigraphy with Tc-DMSA single-photon emission computed tomography (SPECT) for the detection of renal cortical scars in patients with chronic kidney disease stage-3 (CKD-3). PATIENTS AND METHODS: Data of 40 patients (mean age: 43.7±15.3 years, 29 men, 11 women) who underwent planar Tc-DMSA along with regional Tc-DMSA SPECT for the detection of renal cortical scars were prospectively evaluated. All the patients had CKD-3, with a mean serum creatinine level of 2.23±1.85 g/dl. Planar and SPECT Tc-DMSA images were evaluated by two nuclear medicine readers independently. Each kidney was divided into 12 cortical segments. A cortical segment was recorded as abnormal if it had reduced or absent radiotracer activity. The linear correlation coefficient (r value) for the number of abnormal segments detected between readers was calculated for planar imaging, SPECT, and between the two techniques for both the readers. RESULTS: For both observers, the average correlation coefficient for SPECT (r=0.87) and planar imaging (r=0.90) was high (P<0.0001). A moderately strong linear correlation was also observed between readers for planar imaging and SPECT (r=0.78 and 0.71, P<0.0001). There was no significant difference in the average number of abnormal segments detected by planar versus SPECT imaging: 2.1 for planar imaging and 2.8 for SPECT (P=0.06, two-tailed). In 15% of patients, SPECT detected cortical defects not appreciated on planar imaging. CONCLUSION: Tc-DMSA renal cortical imaging using dual-head SPECT offers no statistically significant diagnostic advantage over planar imaging for the detection of cortical defects in patients with CKD-3.

Metastatic superscan in prostate carcinoma on gallium-68-prostate-specific membrane antigen positron emission tomography/computed tomography scan.

We describe the imaging features of a metastatic superscan on gallium-68 Glu-NH-CO-NH-Lys-(Ahx)-[Ga-68(HBED-CC)], abbreviated as gallium-68-prostate-specific membrane antigen ((68)Ga-PSMA) positron emission tomography/computed tomography (PET/CT) imaging. (68)Ga-PSMA is novel radiotracer undergoing evaluation for PET/CT imaging of prostate carcinoma. This patient had a superscan of metastases on conventional bone scintigraphy and was referred for (68)Ga-PSMA PET/CT to evaluate the feasibility of (177)Lu-PSMA therapy.

Bilateral Renal Involvement in Mantle Cell Lymphoma on FDG PET/CT.

Mantle cell lymphoma (MCL) is a rare aggressive lymphoid neoplasm occurring in approximately 3% to 10% of non-Hodgkin lymphomas. Renal involvement is rarely reported in case of MCL. We hereby described a case of MCL in a 76-year-old man in whom bilateral renal involvement was detected on FDG PET/CT. The patient underwent chemotherapy, and follow-up PET/CT reveals resolution of the renal lesions.

Digital contrast enhancement of (18)Fluorine-fluorodeoxyglucose positron emission tomography images in hepatocellular carcinoma.

PURPOSE: The role of (18)fluorodeoxyglucose positron emission tomography (PET) is limited for detection of primary hepatocellular carcinoma (HCC) due to low contrast to the tumor, and normal hepatocytes (background). The aim of the present study was to improve the contrast between the tumor and background by standardizing the input parameters of a digital contrast enhancement technique. MATERIALS AND METHODS: A transverse slice of PET image was adjusted for the best possible contrast, and saved in JPEG 2000 format. We processed this image with a contrast enhancement technique using 847 possible combinations of input parameters (threshold "m" and slope "e"). The input parameters which resulted in an image having a high value of 2(nd) order entropy, and edge content, and low value of absolute mean brightness error, and saturation evaluation metrics, were considered as standardized input parameters. The same process was repeated for total nine PET-computed tomography studies, thus analyzing 7623 images. RESULTS: The selected digital contrast enhancement technique increased the contrast between the HCC tumor and background. In seven out of nine images, the standardized input parameters "m" had values between 150 and 160, and for other two images values were 138 and 175, respectively. The value of slope "e" was 4 in 4 images, 3 in 3 images and 1 in 2 images. It was found that it is important to optimize the input parameters for the best possible contrast for each image; a particular value was not sufficient for all the HCC images. CONCLUSION: The use of above digital contrast enhancement technique improves the tumor to background ratio in PET images of HCC and appears to be useful. Further clinical validation of this finding is warranted.

Mammillary Body: Chronic Refractory Epilepsy Seizure Focus Detected by 18F-FDG PET-CT.

Epilepsy is one of the most common neurological conditions, which affect nearly 1% of the entire population. We present F-FDG PET-CT findings of a mammillary body epileptic focus in a 50-year-old woman with a 5-year history of seizure and behavior disturbance and memory problems for the past 4 years.

18F-Fluorodeoxyglucose PET/CT in Langerhans cell histiocytosis: spectrum of manifestations.

The objective of this article is to provide an illustrative tutorial highlighting the utility of 18F-FDG PET/CT imaging to detect the spectrum of manifestations in patients with Langerhans cell histiocytosis. FDG PET/CT is a powerful tool for making an early diagnosis; it allows higher diagnostic confidence with regard to lesions, measuring the extent of disease (staging) and assessing disease activity, and is consequently useful for evaluating the response to therapy in patients with Langerhans cell histiocytosis.

Diuretic 18F-Fluorodeoxyglucose PET/Computed Tomography in Evaluation of Genitourinary Malignancies.

The interpretation of fluorodeoxyglucose (FDG) PET/computed tomography (CT) is often challenging for pelvic pathologies because of the physiologic bowel and urinary tract activity. Intense radiotracer activity in urinary tract interferes in image interpretation and leads to false-negative results in diagnosis and detection of local recurrence and regional lymph node metastases. It is imperative to minimize unnecessary urinary bladder activity to improve the diagnostic yield of PET/CT. All the techniques described in the literature have their pros and cons. This article discusses FDG PET/CT in evaluation of urinary bladder cancer, cervical cancer, and ovarian cancer.

Incremental value of 99mTc-MDP hybrid SPECT/CT over planar scintigraphy and SPECT in avascular necrosis of the femoral head.

OBJECTIVE: The aim of the study was to evaluate the incremental value of technetium-99m-methylene diphosphonate (99mTc-MDP) single-photon emission tomography/computed tomography (SPECT/CT) over planar bone scintigraphy (BS) and SPECT in the diagnosis of avascular necrosis (AVN) of the femoral head. MATERIALS AND METHODS: The data of 44 patients (mean age 36 ± 16 years, 34 male and 10 female) who underwent 99mTc-MDP BS along with regional SPECT/CT for suspected femoral head AVN were retrospectively evaluated. Planar BS, SPECT and SPECT/CT images were evaluated by two nuclear medicine physicians in consensus. On the basis of diagnostic confidence, a score of 1-5 was given, with 1 being definitely AVN, 2 being probably AVN, 3 being equivocal, 4 being probably normal and 5 being definitely normal. Receiver operating characteristic analysis was performed and the area under the curve was calculated. For calculation of sensitivity, specificity and predictive values for planar, an interpretive score of less than or equal to 2 was taken as AVN and a score of 3 or more was taken as no AVN. Clinical and imaging follow-up and histopathological results were taken as the reference standard. RESULTS: Among 44 patients with 64 affected femoral heads, there were 48 true-positive, 13 true-negative, two false-positive and one false-negative lesion on SPECT/CT. The diagnostic accuracy of planar BS, SPECT and SPECT/CT was 67, 78 and 95%, respectively. Planar BS was found to have the lowest sensitivity (75%) and specificity (40%), whereas SPECT/CT had the highest sensitivity (98%) and specificity (87%). The area under the curve was highest for SPECT/CT (0.919), followed by SPECT (0.76) and planar BS (0.567). SPECT/CT was superior to both SPECT (P = 0.02) and planar BS (P < 0.001), whereas SPECT was superior to planar BS (P = 0.03). CONCLUSION: SPECT/CT is superior to planar BS and SPECT alone for the diagnosis of AVN of the femoral head.

Importance of SPECT/CT in detecting multiple hemangiomas on 99mTc-labeled RBC blood pool scintigraphy.

Vascular malformations and hemangiomas are common in children, but gastric hemangioma is extremely rare with less than 15 reported cases in the pediatric age group. Gastric hemangioma accounts for only 0.05% of all gastrointestinal neoplasms, and intra-abdominal hemangiomas are rarely found outside of the liver. We present a unique case of gastric hemangioma, and multiple hemangiomas were detected in a single scan by 99mTc-labeled RBC blood pool imaging. This case also depicts the incremental role of SPECT/CT over planar acquisition for detecting multiple hemangiomas, especially for those lesions located adjacent to physiological blood pool activity.

(177)Lu-EDTMP for palliation of pain from bone metastases in patients with prostate and breast cancer: a phase II study.

PURPOSE: The purpose of this study was to evaluate the efficacy and safety of (177)Lu-EDTMP for pain palliation in patients with bone metastases from castration-resistant prostate and breast cancer. The secondary objective was to compare low-dose and high-dose (177)Lu-EDTMP in bone pain palliation. METHODS: Included in the study were 44 patients with documented breast carcinoma (12 patients; age 47 ± 13 years) or castration-resistant prostate carcinoma (32 patients; age 66 ± 9 years) and skeletal metastases. Patients were randomized into two equal groups treated with (177)Lu-EDTMP intravenously at a dose of 1,295 MBq (group A) or 2,590 MBq (group B). Pain palliation was evaluated using a visual analogue score (VAS), analgesic score (AS) and Karnofsky performance score (KPS) up to 16 weeks. Toxicity was assessed in terms of haematological and renal parameters. RESULTS: The overall response rate (in all 44 patients) was 86 %. Complete, partial and minimal responses were seen in 6 patients (13 %), 21 patients (48 %) and 11 patients (25 %), respectively. A favourable response was seen in 27 patients (84 %) with prostate cancer and in 11 patients (92 %) with breast cancer. There was a progressive decrease in the VAS from baseline up to 4 weeks (p < 0.05). Also, AS decreased significantly from 1.8 ± 0.7 to 1.2 ± 0.9 (p < 0.0001). There was an improvement in quality of life of the patients as reflected by an increase in mean KPS from 56 ± 5 to 75 ± 7 (p < 0.0001). The overall response rate in group A was 77 % compared to 95 % in group B (p = 0.188). There was a significant decrease in VAS and AS accompanied by an increase in KPS in both groups. Nonserious haematological toxicity (grade I/II) was observed in 15 patients (34 %) and serious toxicity (grade III/IV) occurred in 10 patients (23 %). There was no statistically significant difference in haematological toxicity between the groups. CONCLUSION: (177)Lu-EDTMP was found to be a safe and effective radiopharmaceutical for bone pain palliation in patients with metastatic prostate and breast carcinoma. There were no differences in efficacy or toxicity between patients receiving low-dose and high-dose (177)Lu-EDTMP.