Molecular Imaging and Radionuclide Therapy最新文献

Truncation artifact during single-photon emission computed tomography occurs when some part of body, such as left ventricle in myocardial perfusion imaging, lies outside the field-of-view during image acquisition. Improper adjustment of axis of rotation of detectors regarding the patient on the scanning table is the main cause. Large or slim patient body habitus is reported as source of this artifact. However, there may be other sources including that in our case, in which the artifact was present in prone position but not in supine imaging. The appearance was one-sided incremental cropping of projections of one of detectors and a wedge-shaped or triangular defect in the corresponding sinogram. This finding may suggest a possible mechanical instability of the gantry during motion over the patient's left side in prone imaging.

Spondyloepiphyseal dysplasia tarda (SEDT) is a rare X-linked skeletal disorder affecting the spine and long bones, leading to short stature, spinal deformities, and joint stiffness. It is caused by genetic mutations, and primarily affects males. Diagnosis is confirmed by imaging and genetic testing. We report the case of a 33 years old patient with a history of X-linked SEDT, who presented with pain in the lower limbs and pelvis, accompanied by limited mobility. Bone scan with ⁹⁹mTc-methylene diphosphonate (MDP) revealed a polyostotic SEDT involvement, periarticular ossifications, and bony bridges in the active phase. The authors highlight the role of bone scan with ⁹⁹mTc-MDP in diagnosing this rare disease.

Objectives: The increasing use of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) imaging has led to the frequent detection of incidentalomas. This study aimed to investigate the prevalence, locations, malignancy rates, and clinical evaluations of incidentalomas detected during preoperative staging with ¹⁸F-FDG PET/CT in patients with surgically relevant primary tumors.

Methods: A total of 251 patients who underwent preoperative ¹⁸F-FDG PET/CT imaging between January 2019 and December 2023 were retrospectively analyzed. Incidental uptake sites were classified into six anatomical regions: thyroid, colon, rectum, prostate, cervix/uterus, and breast. Data regarding maximum standardized uptake value (SUV_max) values, biopsy status, imaging follow-up, and histopathological outcomes were recorded and compared with population-based incidence data from the literature.

Results: The most frequent incidentalomas were detected in the thyroid (11.6%), followed by cervix/uterus (9.6%), colon (7.6%), prostate (4.4%), breast (2.4%), and rectum (2.0%). Malignancy was confirmed in incidentalomas of the thyroid (85.7%), prostate (83.3%), colon (71.4%), rectum (50.0%), and breast (33.3%). Malignancy rates for the thyroid, breast, colorectal, and prostate groups were significantly higher than population-based estimates (p<0.05). No statistically significant correlation was found between SUV_max and malignancy status across localization groups.

Conclusion: Incidental findings on ¹⁸F-FDG PET/CT imaging are common and carry a considerable risk of malignancy, particularly in thyroid, prostate, and colorectal sites. Given the observed diagnostic yield, further clinical evaluation, including tissue diagnosis, should be considered in cases with focal uptake, especially when located in high-risk anatomical regions. Awareness of these findings is essential for timely management and appropriate therapeutic decision-making.

Distant metastases from well-differentiated thyroid carcinoma typically involve the lungs and bones. We report a rare case of metastatic papillary thyroid carcinoma presenting as soft tissue lesion, detected by Iodine-131 whole-body scintigraphy in a 44-year-old asymptomatic male. The patient had previously undergone a total thyroidectomy and bilateral modified radical neck dissection, receiving radioiodine for pT3bN1bMx multifocal classical papillary thyroid carcinoma. Further evaluation with ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography revealed additional sites of soft tissue and muscle metastasis, along with extensive nodal, lung, and skeletal involvement. These findings indicated advanced disease with a poor prognosis, necessitating a change in the treatment plan.

Fibroblast activation protein (FAPI), a type II transmembrane glycoprotein is a promising target to image epithelial originated cancers. Pancreatic cancer is characterized with [⁶⁸Ga]Ga-FAPI-04 and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake in varying degree. However physiologic uptake and uptake associated with acute/chronic pancreatitis makes interpretation challenging. We would like to present a case of pancreatic cancer whose tumor could not delineated from rest pancreatic tissue in [⁶⁸Ga]Ga-FAPI-04 positron emission tomography/computed tomography (PET/CT) images due to intense FAPI uptake in whole pancreas but more remarkable in ¹⁸F-FDG PET/CT images.

A 63-year-old woman presented to the emergency department with dyspnea, chest pain, and a palpable right breast mass. Non-contrast thoracic computed tomography (CT) scan revealed suspicious lesions in the right upper lung lobe and right breast, as well as right pleural effusion. For further evaluation, ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT scan was performed. There was increased FDG uptake in the right breast, right lung, liver, bones, and lymph nodes. Histopathological assessment confirmed that the breast mass was a metastatic lesion originating from a primary small-cell lung carcinoma. The manifestation of primary lung carcinoma with a metastatic mass lesion in the breast region is a rare condition. The manifestation can lead to diagnostic challenges, particularly when distinguishing it from a primary breast tumor. ¹⁸F-FDG PET/CT may provide valuable information for staging and surveillance, especially in patients with atypical metastatic patterns. This case highlights that unexpected metastatic sites can significantly affect treatment strategies and are frequently associated with worse prognosis.

Objectives: We record quantitative differences between ¹⁸F-prostate specific membrane antigen (¹⁸F-PSMA)-1007 and [⁶⁸Ga]Ga-PSMA-11 positron emission tomography (PET) prostate scans at our centre to investigate if significant differences exist between suspected lesion and lesion/ background parameters studied. We also assess the potential impact of such differences on tracer interchangeability when supply is constrained.

Methods: Sixty-one [⁶⁸Ga]Ga-PSMA-11 and seventy-two ¹⁸F-PSMA-1007 patients were analysed in two cohorts, each comprising 200 lesions. Clinical reports were used to determine maximum standard uptake values (SUV_max) was recorded for suspected lesions (T). Similarly, normalisations of mean standardized uptake (SUV_mean) and standardized uptake value-peak (SUV_peak) using lean body mass (SUV_Ibm) and body surface area (SUV_bsa) were estimated. SUV_mean of liver backgrounds (B) was recorded to estimate T/B ratios. Metabolic tumour volume and total lesion PSMA (TL-PSMA) were investigated as functional volume surrogates. The Mann-Whitney U test was used to identify significant differences between the [⁶⁸Ga]Ga-PSMA-11 and ¹⁸F-PSMA-1007 distributions.

Results: Significant differences were observed for lesion SUV_max (p=0.0004), SUV_peak (p=0.0017), SUV_mean (p=0.0007), SUV_Ibm (p=0.0002), and SUV_bsa (p=0.0005) in lesions with higher [⁶⁸Ga]Ga-PSMA-11 SUV. Similarly, significant differences were observed in liver SUV_max (p<0.0001), SUV_peak (p<0.0001), and SUV_mean (p<0.0001), with higher values for ¹⁸F-PSMA-1007. T/B (p<0.0001) and TL-PSMA (p=0.0063) also exhibited significantly higher [⁶⁸Ga]Ga-PSMA-11 values.

Conclusion: Consistent, predictable, and significant differences were observed in ¹⁸F-PSMA-1007 and [⁶⁸Ga]Ga-PSMA-11 PET scans of lesion, liver, volume surrogates, supporting tracer interchangeability for patients with suspected prostate cancer. Our results also support the recent commissioning of PSMA-based PET tracers in England.

Objectives: This study investigates the effects of high-dose radioactive iodine therapy on gonadotropin and sex hormone levels, and on sperm parameters in male patients with differentiated thyroid carcinoma following thyroidectomy.

Methods: Twenty-five male patients (aged 20-60 years) with differentiated thyroid carcinoma underwent thyroidectomy and iodine therapy. The therapeutic dose was 150 mCi of oral sodium iodide solution. Levels of gonadotropins, sex hormones, and anti-Müllerian hormone (AMH) were measured before and two weeks after radioiodine therapy (RT). Semen analysis included liquefaction, odor, color, viscosity, agglutination, and aggregation. The main parameters evaluated were semen volume, pH, sperm count, percentages of motile and progressively motile sperm, round cells, and sperm morphology. Sperm motility, including progressive, non-progressive, and immotile types, and DNA fragmentation were analyzed according to World Health Organization guidelines.

Results: The Wilcoxon signed-rank test was used with a significance level of p≤0.05. Follicle-stimulating hormone levels in patients' sera were significantly higher than pre-RIT measurements (p=0.002), whereas luteinizing hormone, dihydrotestosterone, dehydroepiandrosterone sulfate, testosterone, and AMH levels were not significantly different from pre-RT measurements. Total sperm count, volume, motility, and rapid progressive motility increased significantly compared to pre-radioiodine ablation measurements, while other parameters remained unchanged.

Conclusion: Male patients who received 150 mCi of radioactive iodine showed no impairment in fertility. Long-term follow-up studies with larger sample sizes are crucial to investigate the physiological roles of gonadal hormones, sperm DNA fragmentation, and AMH in the testes after RIT.

¹⁸Fluorine-fluorocholine (¹⁸F-FCH) is a radiopharmaceutical used in primary hyperparathyroidism. The data about its utility in malignancies other than prostate and hepatocellular carcinoma is limited. We present the case of a patient who was referred for ¹⁸F-FCH positron emission tomography/computed tomography (PET/CT) due to the persistently elevated parathormone and calcium levels following total thyroidectomy with left lower parathyroidectomy for parathyroid carcinoma (PTC). Previously, the patient underwent ¹⁸Fluorine-fluorodeoxyglucose (¹⁸F-FDG) PET/CT. The latter method detected multiple mediastinal and hilar lymph nodes, as well as nodular lesions in lungs and osteolytic bone lesions with an increased tracer uptake, whereas ¹⁸F-FCH PET/CT detected an increased tracer uptake not only in lesions at all of the abovementioned areas, but also in the nodular lesion in the neck corresponding to a local relapse as well, with bone lesions showing higher avidity for ¹⁸F-FDG than for ¹⁸F-FCH. The case we present shows that ¹⁸F-FCH PET/CT has an additive value to ¹⁸F-FDG PET/CT in an evaluation of patients with PTC.

Objective: The aim of this retrospective study was to investigate the prognostic value of preoperative findings on ¹⁸F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (¹⁸F-FDG PET/MRI) in gastric cancer (GC) patients who underwent total or subtotal gastrectomy.

Methods: Patients with GC who underwent pretreatment staging with ¹⁸F-FDG PET/MRI and subsequently underwent total or subtotal gastrectomy were included in the study. Demographic and clinicopathologic features of patients were recorded. The maximum wall thickness of gastric tumors, the minimum apparent diffusion coefficient (ADC_min), the total number and maximum standard uptake values (SUV_max) of ¹⁸F-FDG-positive lymph nodes, the short-axis diameter of the largest lymph node, and the tumor SUV_max-to-liver SUV_mean ratio on ¹⁸F-FDG PET/MRI were recorded. Predictors of mortality were evaluated using Cox proportional hazards regression models. Survival analysis was conducted using the Kaplan-Meier method.

Results: Seventy-eight patients with GC who underwent gastrectomy were included in the study. The median follow-up duration was 23.9 months (interquartile range: 33.4); 39 patients (50.0%) died during follow-up. In the multivariate analysis, the tumor SUV_max/liver SUV_mean ratio (p=0.002) and tumor histopathologic group (p<0.001) were identified as independent predictors of overall survival. The mean overall survival was 42.7 months [95% confidence interval (CI): 35.8-49.6]. The mean overall survival in the signet-ring cell carcinoma/other subtypes group (31.4 months; 95% CI: 22.3-40.4) was significantly shorter than that in the adenocarcinoma group (49.2 months; 95% CI: 40.3-58.2) (p=0.019). Patients with a tumor SUV_max/liver SUV_mean ratio greater than 2.6 on ¹⁸F-FDG PET/MRI (35.7 months; 95% CI: 27.6-43.7) had a shorter overall survival than those with a ratio lower than 2.6 (57.1 months; 95% CI: 46.5-67.7) (p=0.005).

Conclusion: The tumor SUV_max-to-liver SUV_mean ratio may serve as a robust imaging biomarker for prognosis and for determining histopathologic subtype in GC patients who underwent total or subtotal gastrectomy.