Dual-time-point PET/CT study protocol can improve the larynx cancer diagnosis.

AIM: To evaluate whether the sequential dual-time-point fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (DTP 18F-FDG PET/CT) study improves the differential diagnosis in the larynx. BACKGROUND: In some cases, the clinical and metabolic similarity of laryngitis and larynx cancer make differential diagnostics difficult when performing standard 18F-FDG PET/CT examinations; therefore, an additional study protocol performance seems to be of reasonable value. MATERIALS AND METHODS: 90 patients (mean age: 61 ± 11 years, range: 41-84 years): 23 women (mean age: 63 ± 10 years, range: 51-84 years) and 67 men (mean age: 61 ± 11 years, range: 41-80 years) underwent delayed 18F-FDG PET/CT examinations at 60 and 90 min post intravenous injection (p.i.) of the radiopharmaceutical 18F-FDG. We compared the metabolic activity of 90 structures divided into following groups: normal larynx (30 patients), laryngitis (30 lesions) and larynx cancer (30 tumors) with maximal and mean standardized uptake value (SUVmax, SUVmean) and the retention index (RI-SUVmax). We used the receiver operating characteristics (ROC) curve to evaluate the SUVmax cut-off values. RESULTS: The SUVmax cut-off value at 60 and 90 min p.i. of 2.3 (sensitivity/specificity: 96.4%/100%) and 2.4 (94.2%/100%), respectively, distinguished normal and abnormal metabolic activity in the larynx. When laryngitis and tumors were compared, the SUVmax cut-off values obtained after initial and delayed imaging were 3.6 (87.5%/52.0%) and 6.1 (58.3%/84%), respectively. The RI-SUVmax of 1.3% (71.4%/88.1%) suggested abnormality, while RI-SUVmax of 6.6%, malignant etiology (75.0%/80.0%). CONCLUSIONS: In this study, the sequential DTP scanning protocol improved the sensitivity and specificity of the PET/CT method in terms of differential diagnosis within the larynx.

Sequential delayed [18 F]FDG PET/CT examinations in the pharynx.

This study aimed to evaluate the usefulness of the biphasic 2-deoxy-2-[18 F]fluoro-D-glucose positron emission tomography/computed tomography ([18 F]FDG PET/CT) examinations in terms of distinguishing benign and malignant lesions within the pharynx. 139 patients underwent sequential biphasic [18 F]FDG PET/CT examinations at 60 and 90 minutes (min) post intravenous injection (p.i.) of the [18 F]FDG. We evaluated the metabolic activity of 93 malignant lesions and 59 benign findings within pharynx as well as 70 normal blood vessels. We evaluated the maximal and mean standardized uptake value (SUVmax, SUVmean) and the retention index (RI-SUVmax). We used the receiver operating characteristics (ROC) analysis to obtain the prognostic metabolic indices cut-off which may differentiate between benign and malignant lesions. The SUVmax value cut-off at 60 and 90 min p.i. differentiating between normal and abnormal metabolic activity in the pharynx was 1.9 and 2.0, respectively. When compared benign and malignant lesions, the SUVmax on initial and delayed scans were 3.1 and 3.6, respectively. In this material, the increase of the SUVmax value over time of 1.7% suggested abnormality, while RI-SUVmax of 5.7% indicated malignant etiology. The biphasic [18 F]FDG PET/CT study protocol is useful in better stratification of normal and abnormal glucose metabolism activity in the pharynx.

Best practice for the nuclear medicine technologist in CT-based attenuation correction and calcium score for nuclear cardiology.

The use of hybrid systems is increasingly growing in Europe and this is progressively important for the final result of diagnostic tests. As an integral part of the hybrid imaging system, computed tomography (CT) plays a crucial role in myocardial perfusion imaging diagnostics. Throughout Europe, a variety of equipment is available and also different university curricula of the nuclear medicine technologist are observed. Hence, the Technologist Committee of the European Association of Nuclear Medicine proposes to identify, through a bibliographic review, the recommendations for best practice in computed tomography applied to attenuation correction and calcium score in myocardial perfusion imaging, which courses in the set of knowledge, skills, and competencies for nuclear medicine technologists. This document aims at providing recommendations for CT acquisition protocols and CT image optimization in nuclear cardiology.

Will Rogers phenomenon in the oesophageal cancer patients staging - CT versus 18F-FDG PET/CT: retrospective study.

OBJECTIVE: The oesophageal cancer is one of the most common and aggressive malignancies, especially in elder man. The method of choice in diagnosis of the oesophageal cancer patients are the contrast-enhanced computed tomography (CT) and the 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) examinations. AIM: This study is to evaluate and compare the contrast-enhanced CT and the 18F-FDG PET/CT methods of imaging in terms of the oesophageal cancer staging and restaging using the eighth edition of the tumor-node-metastasis (TNM) classification. MATERIALS AND METHODS: The studied group consisted of 25 retrospectively analyzed patients (23 men, 2 women; mean age±SD: 60±11 years, range: 33-78 years, median: 62 years, p=0.09) who underwent the contrast-enhanced CT and the 18F-FDG PET/CT scanning within one to eight weeks. All mentioned lesions were histopathologically examined. Among these patients, 12 did not receive any treatment and 13 subjects have been treated with the chemotherapy and the external beam radiotherapy using comparable therapeutic protocols. RESULTS: In 13 subjects PET/CT method occurred as more sensitive in terms of pre- and posttreatment staging than CT and in 10 from 13 cases, involving the 18F-FDG PET/CT imaging into diagnostic management affected the therapeutic protocol. In 11 cases both methods showed comaparable or similar stage of the disease and in 1 patient both methods showed no pathology. CONCLUSION: In this material, the 18F-FDG PET/CT seems to be more accurate in terms of staging in case of the oesophageal cancer TNM classification.

Detection of the Prostate Cancer Bone Metastases: Is It Feasible to Compare 18F-fluorocholine PET/CT, 18F-fluorodeoxyglucose PET/CT and 99mTc-methyl Diphosphonate Bone Scintigraphy?

PURPOSE: The objective was to compare the efficacy of 99mTc-MDP-BS, 18F-FDG-PET/CT and 18F-FCH-PET/CT in detecting bone metastases in prostate cancer patients. MATERIALS AND METHODS: 56 patients diagnosed with prostate cancer underwent 99mTc-methylendiphosphonates bone scintigraphy (99mTc-MDP-BS) and fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) or fluorine-18-fluorocholine PET/CT (18F-FCH-PET/CT) within six weeks. There were 27 patients examined with 99mTc-MDP-BS + 18F-FDG (mean age 67.96 ± 9.04 years) and 29 patients examined with 99mTc-MDP-BS + 18F-FCH (mean age 73.93 ± 8.75 years). The R factor in scintigraphy and semi- quantitative analysis with Standardized Uptake Value (SUV) in the PET/CT were used using semi - automatic methods of bone lesions' contouring. The R factor was calculated as the total count rate in bone metastasis and the total count rate in contralateral area ratio. For further analysis, the mean pixel and the total surface of lesion product in scintigraphy, the Total Lesion Glycolysis (TLG) in the 18F-FDG-PET/CT and the Total Lesion Activity (TLA)in the 18F-FCH-PET/CT were evaluated. RESULTS: The average maximal SUV (SUVmax) value was significantly higher in patients who underwent 18F-FCH-PET/CT than in 18F-FDG-PET/CT (5.17 ± 2.24, 3.71 ± 1.56, P < .05). The R factor differences in both groups (patients who underwent BS and 18F-FDG-PET/CT, BS and 18F-FCH-PET/CT) were insignificant (1.92± 0.87, 2.03 ± 0.57, respectively, P > .05). There was no statistically significant correlation (Pearsons' correlationcoefficient - Rp) between the R factor and the SUVmax within examined groups (Rp = .42; P = .31) and between the R factor and the SUVmean (Rp = .43; P = .28). A high Rp between measured total surface in the BS and volume in the PET/CT of the metastatic lesion was found. In patients who underwent BS + 18F-FDG-PET/CT and BS +18F-FCH-PET/CT, Rp equaled .95 and .70. CONCLUSION: 99mTc-MDP-BS, 18F-FDG-PET/CT and 18F-FCH-PET/CT occurred as comparable imaging methods in bone metastases detection in the prostate cancer patients and provide complementary clinical conclusions.