NUCLEAR MEDICINE REVIEW最新文献

Background: Neuroendocrine neoplasms (NENs) are heterogeneous groups of tumours derived from neuroendocrine cells of the ectoderm or endoderm. They are considered rare, with an estimated incidence and prevalence of 6/100,000 and 35/100,000 respectively, and a noticeable upward trend. Radioligand therapy (RLT) using beta-radiation-emitters combined with somatostatin analogues is an effective and relatively safe treatment method. It is usually used as a second-line therapy in case of progressive disease.

Material and methods: In retrospective analysis covering eight years of observation (2015-2023) of patients treated in a single highest-reference NEN centre, a subgroup of 13 who received RLT re-treatment (¹⁷⁷Lu or ¹⁷⁷Lu/⁹⁰Y-mixture) was identified. Epidemiological aspects, renal, hepatic, haematological parameters and chromogranin A serum concentration were analysed.

Results: The median PFS after the first cycle of RLT was 53.8 months (IQR = 19.3). Directly after the second cycle of RLT disease stabilization and progression was observed in 11/13 (84.6%) and 2/13 (15.4%) patients respectively. After the second cycle of RLT median observation time for the study group was 16.2 months. Eight out of 13 patients were reachable for long-term observation and stabilization was confirmed in 62.5 % (5/8), progression in 12.5% (1/8) and death in 25% (2/8) patients. Median survival time in patients with confirmed death was 7 months. During observation, an increase in creatinine concentration with a decrease in glomerular filtration rate (GFR) was noticed, however, the values were at a statistical trend level (p = 0.056; p = 0.071). The increase of liver parameters was statistically, but not clinically significant. The decrease in albumin concentration and fasting glucose concentration were not significant. An increase in chromogranin A concentration correlated, although not statistically, with the progression of the disease. A statistically significant decrease in the number of all bone marrow cell lines was observed. The first RLT cycle caused a higher decrease in blood parameters than the second. There were no differences in PFS or laboratory parameters depending on the radioligand ([¹⁷⁷Lu]Lu-DOTA-TATE vs. [¹⁷⁷Lu]Lu-DOTA-TATE/[⁹⁰Y]Y-DOTA-TATE).

Conclusions: In follow-up after RLT re-treatment stabilization was observed in 62.5%, progression in 12.5% and death in 25% of patients. Decrease of glomerular filtration, and bone marrow parameters resulted from the cumulative adverse effect of RLT, the natural ageing process, and the progression of the disease. Side effects were mainly caused by the first treatment cycle. There was no significant influence on the measured parameters, depending on the radioisotope used. Re-treatment of RLT seems to be a reliable and relatively safe method, thus should be considered in patients who underwent one cycle of RLT and responded to the t

Incidental uptake in [18F]FDG PET/CT is not uncommon, but uptake in the oral and sinonasal regions was less frequently reported. We present a case of incidental focal [18F]FDG PET/CT uptake within the hard palate, which was later revealed to be an ossifying fibroma. We also reviewed some relevant literature and suggested that further investigation may be necessary for some patients with incidental [18F]FDG PET/CT uptake in the oral and sinonasal regions.

Background: To evaluate the effect of patient-related factors such as age, gender, body mass index (BMI), blood glucose (BG), diabetes, serum creatinine and injected dose on 18F-Fluorodeoxyglucose ([18F]FDG) uptake of tumor and normal organs, as well impact of [18F]FDG uptake of tumor on normal organs, in clinical positron emission tomography-computed tomography (PET/CT).

Material and methods: In this retrospective study, data of 200 patients who underwent clinical [18F]FDG PET/CT with (n = 192) and without (n = 8) intravenous contrast was evaluated. Ten target organs and tumor [18F]FDG uptake were measured with a standardized uptake value maximum (SUVmax). Pearson correlation coefficient was calculated for continuous variables while t-test/Wilcoxon rank sum tests were used to compare continuous outcomes. Multivariate linear regression analysis was done to exclude covariates, followed by posthoc multiple linear regression analysis after adjusting the levels of significance.

Results: Significant but weak positive correlation was seen between tumor [18F]FDG uptake with uptake in the pancreas (r = 0.43, p < 0.001) and heart (r = 0.19, p = 0.049), but not other organs. With age, a significant negative correlation was seen with the brain (r = -0.183, p = 0.009) and a positive correlation was seen with the blood pool (r = 0.205, p = 0.003). With BG, significant negative correlation was seen with the brain (r = -0.449, p < 0.0001) and heart (r = -0.15, p = 0.033), while a positive correlation was seen with fat (r = 0.143, p = 0.043). BMI showed a significant positive correlation with [18F]FDG uptake of all organs except the pancreas and heart, as well as tumor. No significant correlation was seen with serum creatinine and injected [18F]FDG dose. Significantly higher uptake was seen in the brain, spleen, and muscles of females. Between obese and non-obese, a significant difference was seen for all organs except for the pancreas and heart, and tumor. Comparison between non-diabetic and diabetic patients showed significant differences only for bone. Multivariate linear analysis adjusting for cofactors showed only BMI (p = 0.0009) and BG (p = 0.0002) to be independently correlated with [18F]FDG uptake. Post-hoc multiple regression analysis showed a significant positive correlation between [18F]FDG uptake of the brain (β = 0.118, p < 0.001), liver (β = 0.02, p = 0.002), and fat (β = 0.01, p < 0.0006) with BMI, and significant negative correlation of brain uptake with BG (β = 0.03, p < 0.0001).

Conclusions: Tumor [18F]FDG uptake has no significant effect on the uptake in organs, except for the pancreas and heart. Age, gender, BMI, and BG, but not creatinine and injected [18F]FDG dose show correlation with uptake in tumor and organs. BG and BMI are independent significant factors, with a positive correlation of BMI with the brain, hepatic and fat uptake, and a negative cor

Fluorine-18-deoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) has been shown to be superior to other conventional imaging modalities in the detection of extra-nodal lymphomatous localizations. Especially in neurolymphomatosis which is rarely encountered in high-grade lymphomas. We report a case of a woman diagnosed with non-Hodgkin lymphoma, whose initial staging with [18F]FDG PET/CT showed increased [18F]FDG uptake along the brachial and sacral plexuses. [18F]FDG PET/CT remains the most appropriate diagnostic tool in these cases, whose prognosis is often poor.

Prostate-specific membrane antigen (PSMA) is a membrane protein originally discovered in prostate cancer cells. It is widely used at all stages of prostate cancer diagnosis. Several studies have highlighted its possible wide application in other cancers. This review discusses the potential use of positron emission tomography with labelled PSMA for the diagnosis or differentiation of intracranial lesions. Given the numerous reports on the usefulness of PSMA in the diagnosis of brain tumours of glial origin, the focus is on lesions of a different aetiology.

Background: Our aim is to determine the accuracy of [68Ga]Ga-PSMA PET/CT in showing PSMA expression in primary prostate cancer and to investigate the relationship between SUVmax and immunohistochemical PSMA expression, Gleason score, and PSA value.

Material and methods: We retrospectively analyzed 66 male patients who were diagnosed with primary prostate adenocarcinoma, underwent pre-treatment [68Ga]Ga-PSMA PET/CT examination for staging, and performed radical prostatectomy between March 2018-August 2020. Immunohistochemical staining was applied to the radical prostatectomy specimens of all patients to detect PSMA expression. The results were evaluated as an immunoreactive score (IRS) and a modified IRS was obtained. Gleason score groups and prostate-specific antigen (PSA) serum values of the patients were obtained from the patient files.

Results: The high SUVmax of primary prostate tumors was significantly correlated with a high modified IRS score (score 2; 3), high PSA value, high Gleason score, and metastasis. In correlation analysis, a positive correlation was found between SUVmax and PSA value and modified IRS score (r = 0.69, p = 0.001; r = 0.39, p = 0.001). In addition, there was a statistically significant weak correlation between PSA serum concentration and modified IRS scores (r = 0.267; p = 0.03). In regression analysis, the percentage of positive cells had a statistically significant and increasing effect on SUVmax (p = 0.031; std beta = 0.268; 95% CI = 0.231-4.596).

Conclusions: In prostate adenocarcinoma, SUVmax of the primary tumor in [68Ga]Ga-PSMA PET/CT correlates with immunohistochemical PSMA expression. In addition, high SUVmax is associated with markers of poor prognoses, such as high PSMA expression, PSA value, and Gleason score.

A cold vertebral defect is an uncommon finding, especially in Gallium-67-citrate ([67Ga]Ga-citrate) - and [18F]fluorodeoxyglucose ([18F]FDG) - avid lymphomas, representing a diagnostic challenge. Here, we present the case of a patient with non-Hodgkin lymphoma (NHL), in whom the [67Ga]Ga-citrate and [18F]FDG scans showed a diffuse skeletal uptake pattern with concomitant appearance of a cold vertebral defect. Awareness of the different causes of such uptake patterns and accurate clinical information is important to avoid misinterpretation of nuclear studies in oncologic patients.

Background: A challenge for modern medicine is the development of clinical protocols for precise diagnosis and therapy. This study aimed to propose a simple method for modification of 2-[18F]FDG used routinely in hospitals in a way, appropriate for patients' personalized radiopharmaceuticals approach.

Material and methods: For the purposes of the presented study chemo selective method for indirect radiofluorination was applauded to custom synthesized aminooxy- and hydrazine-functionalized tetrazines for 18F-glycolation via oxime or hydrazone formation. 2-[18F]FDG produced with medical baby cyclotron in Nuclear Medicine Clinic at the University Hospital St. Marina-Varna, was used. Thin layer chromatography (TLC) and radio TLC were used to follow the progress of synthesis and to determine radio chemical yield (RCY).

Results: The 2-[18F]FDG was modified with two bifunctional tetrazines aminooxy-acetic acid-6-(2-aminooxy-acetoxy)-[1,2,4,5] tetrazin-3-yl ester (Tz1) and {3-[4-(6-phenyl-[1,2,4,5]tetrazin-3-yl)-phenoxy]-propyl}-hydrazine (Tz2) via oxime and hydrazone formation. The radiolabeling was carried out as one-pot reaction with following parameters: temperature 70-75°C; catalyst p- diaminobenzene (Cat.); pH = 4.2; time 30 minutes; RCY = 70-99%. The radiolabeled tetrazines are appropriate for further bioorthogonal (pretargeting) strategy by click reactions with trans-cyclooctene conjugated bioactive molecules. The methodology is applicable to standard clinical conditions.