Molecular Imaging and Radionuclide Therapy最新文献

An 82-year-old patient with high-risk prostate adenocarcinoma, previously treated with radiotherapy and hormone therapy, presented with biochemical recurrence, as evidenced by a prostate-specific antigen level of 10 ng/mL. A positron emission tomography/computed tomography (PET/CT) scan using ¹⁸F-prostate-specific membrane antigen (PSMA ) 1007 revealed significant uptake at the prostate apex and multiple hypermetabolic osseous lesions in the sternum and L3, suggestive of local recurrence and metastasis. However, several hypermetabolic foci in the abdominopelvic region raised suspicion for potential involvement of the lumbar-aortic lymph nodes due to their moderate to intense uptake. After further investigation, these findings were attributed to active aortic calcifications. This case highlights a rare cause of false-positive results in ¹⁸F-PSMA 1007 PET/CT imaging and underscores the need for additional evaluations, such as abdominopelvic magnetic resonance imaging and renal and phosphocalcic assessments, when such results are suspected.

A 68-year-old man with progressive exertional dyspnea after an upper respiratory tract infection underwent contrast-enhanced thorax computed tomography (CT) to exclude pulmonary thromboembolism. The radiological findings suggested pneumonia or alveolar edema. ¹⁸F-Fluorodeoxyglucose positron emission tomography/CT (¹⁸F-FDG PET) scan was conducted due to progressive radiological findings. It revealed increased FDG uptake in the prostate gland, mediastinal, abdominopelvic multiple lymph nodes and bilateral lung lesions. ⁶⁸Ga- prostate-specific membrane antigen-11 (PSMA) PET/CT scan was performed due to low FDG uptake in the lymph nodes and elevated plasma total prostate-specific antigen values. Moderate to high PSMA uptake corresponded to the localizations of FDG uptake on PET/CT. Furthermore, histopathological and immunohistochemical examinations demonstrated that the bilateral lung lesions and bilateral pleural effusion were compatible with metastases from prostate adenocarcinoma.

Prostate-specific membrane antigen (PSMA)-targeted radionuclide therapy has become an established treatment option for metastatic castration-resistant prostate cancer. Although lutetium-177 (¹⁷⁷Lu) PSMA therapy has shown promising clinical benefits, terbium-161 (¹⁶¹Tb) PSMA is an emerging theranostic agent offering potential advantages due to its combination of beta and Auger electron emissions. This work presents the first documented case in Thailand and Southeast Asia of a patient treated at Ramathibodi Hospital with ¹⁶¹Tb-PSMA following progression on ¹⁷⁷Lu-PSMA therapy. This report describes the clinical application of this novel radiopharmaceutical, the implementation of quantitative imaging protocols, single photon emission computed tomography/computed tomography calibration processes, and absorbed dose estimations from voxel-based dosimetry that contributed to individualised treatment planning.

A 44-year-old female presented with recent history of ischemic strokes and hypercoagulability and chronic alcoholic cirrhosis. ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography was performed during the workup for vasculitis. PET features of vasculitis were not identified, but liver showed multiple hepatic FDG avid foci, concerning for malignant or metastatic disease in the background of cirrhosis of liver. To characterize these lesions, liver magnetic resonance imaging was subsequently performed which revealed hepatic vascular shunts corresponding to the sites of the FDG avid foci. This case highlights potential interpretation n pitfall arising due to FDG avidity in the vascular shunts resembling malignant or metastatic lesions.

Objectives: To develop and evaluate automated segmentation models for the liver and hepatic tumors on ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) using SwinUNETR and residual UNET architectures, and to assess their accuracy in complex clinical cases.

Methods: In this single-center retrospective study, 100 patients (48 males, 52 females; mean age 61±14 years) with ¹⁸F-FDG-avid hepatic lesions from various primary malignancies were included. Liver segmentation was performed on non-contrast CT images using pairs of SwinUNETR and residual UNET models, and tumor segmentation was performed on masked PET images using separately trained pair of SwinUNETR and residual UNET model. Model performance was evaluated using the dice similarity coefficient (DSC), volumetric bias, and Bland-Altman analysis for metabolic tumor volume (MTV) and total lesion glycolysis (TLG).

Results: For liver segmentation, SwinUNETR achieved a median DSC of 97.59% (range: 95.41-98.93%) with a median volumetric bias of -0.94% (LoA: -3.76% to +0.50%), while residual UNET achieved a median DSC of 97.85% (range: 94.81-98.80%) with a median volumetric bias of -0.34% (LoA: -2.63% to +1.16%). For tumor segmentation, SwinUNETR achieved a median DSC of 92.62% (range: 80.75-97.46%), an MTV bias of -8.60% (LoA: -31.62% to +1.21%), and a TLG bias of -6.40% (LoA: -25.58% to +0.76%). Residual UNET achieved a median DSC of 93.07% (range: 80.74-98.18%), MTV bias of -4.33% (LoA: -24.36% to +10.12%), and TLG bias of -11.10% (LoA: -30.8% to +4.52%). Most MTV and TLG measurements were within ±10% of reference values.

Conclusion: Both SwinUNETR and Residual UNET achieved excellent liver segmentation accuracy and clinically acceptable tumor segmentation performance on ¹⁸F-FDG PET/CT, with SwinUNETR showing slightly better performance in liver volumetric measurements. These open-source models could be integrated into clinical workflows to automate segmentation tasks, facilitate treatment planning for liver-directed therapies, and support reproducible quantitative imaging analyses.

A 49-year-old premenopausal woman with a history of left modified radical mastectomy and axillary lymph node dissection for invasive lobular carcinoma three years ago, underwent ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) due to gradually increasing CA15-9 and CEA levels during routine follow-up. Compared with previous ¹⁸F-FDG PET/CT images, the left ovary in the current images showed increased size and radiotracer uptake. Subsequently, total abdominal hysterectomy and bilateral salpingo-oophorectomy were performed, and histopathological evaluation confirmed unilateral metastasis in the left ovary due to primary breast cancer. Although rare, possible isolated ovarian metastasis should be considered in patients with breast cancer who have increased size and radiotracer uptake in ovarian tissue on follow-up ¹⁸F-FDG PET/CT scans.

Positron emission tomography/computed tomography (PET/CT) with Galium-68 prostate-specific membrane antigen (⁶⁸Ga-PSMA) PET/CT) is a valuable tool for initial staging, recurrence detection, and assessment of treatment response in men with prostate cancer. Metastatic spread to regional and distant lymph nodes, bone, lung and liver is well known and expected in patients with castration-resistant disease. However, the application of a highly sensitive whole-body imaging modality such as ⁶⁸Ga-PSMA PET/CT can reveal metastatic foci in rare or unusual locations. We present the case of an 82-year-old patient with prostate adenocarcinoma who underwent long-term androgen deprivation therapy. A ⁶⁸Ga-PSMA PET/CT scan was performed in June 2021 due to significant prostate-specific antigen elevation and revealed disease progression with widespread regional and distant metastases, including a soft-tissue mass in the right breast that demonstrated intense radiotracer uptake; this mass was subsequently resected and histologically confirmed. This case underscores the excellent diagnostic performance of ⁶⁸Ga-PSMA PET/CT for atypical metastatic sites.

A hydatid cyst is a zoonotic infection caused by Echinococcus granulosus. The liver and lungs are the most affected organs. Although rare, osseous involvement by hydatid cyst disease can occur because the rigid bone trabeculae prevent formation of the characteristic adventitia. While fluorodeoxyglucose (FDG) positron emission tomography (PET) findings in hepatic and pulmonary hydatid cysts are well described, this case, to the best of our knowledge, represents the first report of bone hydatid disease located in an extremity evaluated by ¹⁸F-FDG PET/computed tomography.

Tuberculosis (TB) remains a significant public health problem in developing countries, but its diagnosis can be challenging as it may mimic malignancy or other granulomatous diseases. Although pulmonary TB is the most common form, TB can spread hematogenously, lymphatically, or by direct extension to any tissue or organ. We report a 62-year-old female who underwent ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for malignancy evaluation, was diagnosed with extrapulmonary TB, and had her treatment response assessed with ¹⁸F-FDG PET/CT.