Dual 177 Lu-Prostate-Specific Membrane Antigen and 177 Lu-DOTATATE Therapy in Metastatic Castration-Resistant Prostate Cancer With Neuroendocrine Differentiation.

ABSTRACT: We present an 87-year-old man diagnosed with prostate cancer and neuroendocrine differentiation, posttherapy results to consecutive 177 Lu-prostate-specific membrane antigen and 177 Lu-DOTATATE. Despite hormonal therapy and chemoradiotherapy, the patient progressed rapidly, and multiple liver and bone metastases showed regression after 177 Lu-prostate-specific membrane antigen and 177 Lu-DOTATATE treatment. Prostate cancer with neuroendocrine differentiation is resistant to treatments; however, treatment with the combination of 177 Lu-DOTATATE therapy may be promising.

Two Rare Benign Lesions on 18F-FDG PET/CT: Peliosis Hepatis and SANT.

Peliosis hepatis (PH) and sclerosing angiomatoid nodular transformation of the spleen are uncommon benign lesions. Diagnosis can be difficult in some patients. Herein, we present the case of a 28-year-old woman referred with abdominal pain who had spleen lesions. 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography revealed multiple non-FDG avid lesions in the liver and hypermetabolic lesions in the spleen. In addition, abdominal magnetic resonance imaging was performed. Histopathology revealed sclerosing angiomatoid nodular transformation in the spleen and PH in the liver.

68 Ga-PSMA PET/CT Found Lower Respiratory Tract Inflammation Due to Inhaler Use.

ABSTRACT: Prostate-specific membrane antigen (PSMA) is a transmembrane protein physiologically expressed in nonprostatic tissues. Inflammation and infectious diseases could show false-positive PSMA uptake. Herein, we present a 55-year-old patient's findings of inflammation in the lower respiratory tract due to inhaler use in 68 Ga-PSMA PET/CT in a patient with prostate cancer.

Contribution of 68 Ga-DOTA-FAPI-04 PET/CT to Prostate Cancer Imaging : Complementary Role in PSMA-Negative Cases.

PURPOSE: Prostate-specific membrane antigen (PSMA)-targeted PET/CT is a well-established imaging method in prostate cancer (PC) for both staging and restaging, and also for theranostic applications. An alternative imaging method is crucial for 15% PSMA-negative cases. We aimed to investigate the contribution of 68 Ga-DOTA-FAPI-04 PET/CT to PC imaging. PATIENTS AND METHODS: Thirty-six patients diagnosed with PC were included. Patients underwent both 68 Ga-PSMA PET/CT and 68 Ga-DOTA-FAPI-04 PET/CT imaging within 1 week. In staging group, primary tumor uptake values were compared, and also correlations were done with histopathological findings, MRI findings, and total PSA levels. In biochemical recurrence group, the uptake values in prostatic region and metastases were evaluated to define the local recurrence or metastatic disease. RESULTS: In staging group, PSMA PET showed increased uptake in the primary lesion area in 14/27 (52%) patients, whereas 20/27 (74%) patients were positive in FAPI-04 PET. FAPI-04 positivity was found to be quite high, such as 54%, in PSMA-negative patients. A significant difference was observed between ISUP grade 1-3 patients and ISUP grade 4-5 patients in FAPI-04 PET ( P = 0.03). Local recurrence was detected in 3 patients, pelvic lymph node metastasis in 1 patient, and sacrum metastasis in 1 patient in biochemical recurrence group, and all of the lesions had more intense uptake in PSMA PET than FAPI-04 PET. CONCLUSIONS: FAPI PET imaging seems to have a potential to contribute PSMA PET imaging with FAPI positivity in more than half of PSMA-negative cases. Also, FAPI-targeted radionuclide therapy may be a promising method in patients resistant to PSMA-targeted therapy.

Pneumonia with Intense 68Ga-FAPI Uptake Mimicking Metastasis on 68Ga-FAPI PET/CT in a Patient with Rectal Cancer.

A 70-year-old man with newly diagnosed rectum adenocarcinoma was referred to 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for staging, and 68Ga-fibroblast activation protein inhibitor (FAPI)-04 PET/CT for ongoing trial. Both 18F-FDG PET/CT and 68Ga-FAPI-04 PET/CT showed intense uptake in the primary rectal tumor, and also in nodular areas in the right lung. Due to intense 68Ga-FAPI-04 and 18F-FDG uptake, the lung lesions were considered as metastases. However the lesions were reduced in size on CT after 20 days antibiotherapy and diagnosed as pneumonia.

The potential role of 68Ga-FAPI-04 PET/CT for screening malignancy in suspected colonic lesions.

AIM: Benign colonic lesions like tubular adenoma may show intense uptake on F-18-FDG PET/CT and can be mistaken for malignancy. In this study, we evaluated the role of 68Ga-FAPI-04 PET/CT for discriminating the benign and malignant colonic lesions. METHODS: Forty patients with diagnosis of colorectal cancer who had undergone 18F-FDG-PET/CT and 68Ga-FAPI-04 PET/CT for initial staging were retrospectively analyzed. The unexpected foci of uptake in colon on 18F-FDG PET/CT were compared with 68Ga-FAPI-04 PET/CT with lesion and background SUVmax. RESULTS: The primary colorectal lesion SUVmax on both PET/CTs was similar. A total of 9 incidental colon lesions in 7 patients were detected showing intense 18F-FDG uptake and no 68Ga-FAPI-04 uptake. All of the lesions were consistent with tubular adenoma histopathologically. CONCLUSION: 68Ga-FAPI PET/CT may have a crucial role for discrimination of benign and malignant colonic lesions and avoid the unnecessary interventions and extended surgeries in patients with colorectal cancer.

68 Ga-FAPI-04 PET/CT in Selected Breast Cancer Patients With Low FDG Affinity : A Head-to-Head Comparative Study.

PURPOSE: In this prospective study, PET findings of 18 F-FDG PET/CT in breast cancer staging were compared with 68 Ga-FAP inhibitor (FAPI) 04 PET/CT findings in selected cases with relatively low 18 F-FDG uptake in the primary tumor or with suspected nodal or distant metastases. PATIENTS AND METHODS: Twenty-four women with a median age of 45 years (range, 36-67 years) who underwent initial staging 18 F-FDG PET/CT for breast cancer underwent 68 Ga-FAPI-04 PET/CT imaging within the same week. SUV max and quantities of primary tumors and locoregional and distant metastatic lesions were recorded from both images, and these data were compared statistically. RESULTS: The histological subtypes of primary tumors were 11 invasive lobular, 8 invasive ductal, and 5 mucinous subtypes. More intense 68 Ga-FAPI-04 uptake (mean, 17.1 ± 7.9; 7.4-38.5) was detected in all primary tumoral lesions compared with 18 F-FDG (mean, 6.3 ± 3.9; 1.5-20.5) ( P = <0.001, Z = 4.107). Additional lesions showing 68 Ga-FAPI-04 uptake in the breast were detected in 29.2% (n = 7) of patients. In 8.3% (n = 2) of the patients, the primary lesion showed only 68 Ga-FAPI-04 uptake. In 68 Ga-FAPI-04 PET/CT, 25% (n = 6) of the patients showed more lymph node involvement and more intense uptake in the ipsilateral axilla. In addition, infraclavicular (level 3) lymph nodes in 4 patients (16.7%), supraclavicular lymph nodes in 1 patient, and internal mammary lymph nodes in 1 patient were detected only on 68 Ga-FAPI-04 PET/CT. In a patient with lung and bone metastases, 68 Ga-FAPI-04 uptake was higher, and the lung nodule showed only 68 Ga-FAPI-04 uptake. CONCLUSIONS: In selected low-FDG-affinity breast cancer patients, 68 Ga-FAPI-04 PET/CT showed the primary tumor with higher sensitivity and higher SUV max values compared with 18 F-FDG PET/CT. In addition, it is believed that this method may contribute to the management of patients' treatment by increasing the nodal stage.

68Ga-FAPI-04 PET/CT Findings in Patients with Liver Cirrhosis.

Fibroblast activation protein (FAP) is expressed as a pro-inflammatory agent from fibrous tissue in liver cirrhosis and in the tumor microenvironment. Cirrhosis is the last stage of any chronic liver disease, and the natural course of cirrhosis is the progression from the asymptomatic phase to the symptomatic decompensated phase with the development of ascites. Although various clinical features suggest cirrhosis in patients with chronic liver disease, non-invasive methods should follow the clinical approach before a definitive diagnosis. Herein, we present three cases of liver cirrhosis with fibroblast activation protein inhibitor (FAPI) uptake to demonstrate the usefulness of 68Ga-FAPI-04 positron emission tomography/computed tomography (PET/CT) scan in cirrhosis.

Testicular Metastasis of Jejunal Neuroendocrine Tumor on 68Ga-DOTATATE PET/CT.

Neuroendocrine tumors are slow-growing tumors originating from neuroendocrine cells and capable of metastasis. Most of them are found in the gastrointestinal tract; however, they can also be rarely seen in other organs. Testicular neuroendocrine tumors account for less than 1% of all testicular neoplasms. They may present as primary testicular or secondary tumors from extratesticular sources. Jejunal neuroendocrine tumor metastasis to the testis is extremely rare. We present the case of a 61-year-old man with a jejunal neuroendocrine tumor and metastases to bilateral testicles revealed on Gallium-68-DOTATATE positron emission tomography/computed tomography.

The roles of 68 Ga-PSMA PET/CT and 18 F-FDG PET/CT imaging in patients with triple-negative breast cancer and the association of tissue PSMA and claudin 1, 4, and 7 levels with PET findings.

AIM: Aim of study is to compare the results of Gallium-68-prostate-specific membrane antigen ( 68 Ga-PSMA) and 18 F-fluorodeoxyglucose ( 18 F-FDG) positron emission tomography(PET)/computed tomography (CT), to evaluate the correlation between PET findings and the level of PSMA, Claudin (Clau) 1, 4, and 7 receptors obtained by immunohistochemical (IHC) analysis, and to determine potential predictive and prognostic values in TNBC. METHODS: Forty-seven lesions of 42 subjects diagnosed TNBC both underwent PET/CT scan for preoperative staging/restaging were prospectively included study. PSMA, Clau 1, 4, and 7 expressions were IHC evaluated from the biopsy samples of the primary tumor (PT). Maximum standardized uptake value(SUV max) of the PT, lymph node, and distant organ metastases (DOMs) on 18 F-FDG and 68 Ga-PSMA PET/CT were compared with PSMA, Clau 1, 4, and 7 receptor expressions. RESULTS: IHC analyses on 29 BC lesions to demonstrate Clau expression showed 86% (25/29) Clau 1, 86% (25/29) Clau 4, 45% (13/29) Clau 7, and 48% (14/29) PSMA-positive. The mean DOM (SUVmax) was 15.5 ± 11.6 for 18 F-FDG and 6.0 ± 2.9 for 68 Ga-PSMA. Axial diameter of BC PT had a significant positive correlation with 18 F-FDG SUVmax, 68 Ga-PSMA SUVmax, and PSMA scores. BC lesions 68 Ga-PSMA SUVmax had a significant negative correlation with the Ki-67 index. Axial diameter of the primary tumor had significant negative correlation with Clau 7 scores ( r = -0.409, P = 0.034). Absence of Clau 1 expression found to significantly increase the rate of DOM (100% vs. 28%) ( P = 0.014). All patients with axillary lymph node (ALN) metastases ( n = 17, 100%) exhibited Clau 4 positivity ( P = 0.021). The presence of PSMA expression observed to significantly increase the rate of ALN metastases (64.7% vs. 25%) ( P = 0.035). CONCLUSION: Confirming PSMA expression with PET imaging would be significant as PSMA, a theranostic agent, may be a considerable potential agent for radionuclide treatment strategies, in addition to its additional diagnostic contribution to FDG, especially in patients with metastatic TNBC, which is an aggressive, heterogeneous disease.

Effect of Leflunomide Use on 68Ga-DOTATATE Biodistribution in a Case With Neuroendocrine Tumor.

ABSTRACT: A 58-year-old man who underwent surgery for a well-differentiated neuroendocrine tumor of pancreatic origin was evaluated with 68Ga-DOTATATE PET/CT imaging in the follow-up period. After PET/CT findings consistent with disease remission, the patient was started on leflunomide treatment with the diagnosis of rheumatoid arthritis. The patient received leflunomide for 6 months. Then, 68Ga-DOTATATE PET/CT scan was repeated to evaluate the primary disease outcome. Besides the disease remission, we also observed alterations in DOTATATE uptakes of some tissues and organs. In this case, we present the changes in 68Ga-DOTATATE PET/CT scan findings after leflunomide use.

Role of 68 Ga-FAPI PET/CT in Screening Malignancy of Familial Adenomatous Polyposis.

ABSTRACT: A 57-year-old man with familial adenomatous polyposis (FAP) and newly diagnosed colonic adenocarcinoma was referred to 18 F-FDG PET/CT for staging and 68 Ga-FAPI-04 PET/CT for ongoing trial. 18 F-FDG PET/CT showed equal intense 18 F-FDG uptake in the tumor and multiple hypermetabolic polypoid lesions in the entire colorectum. 68 Ga-FAPI-04 PET/CT showed intense 68 Ga-FAPI-04 uptake only at the colonic tumor, without uptake at polypoid lesions.

Chronic Gastritis Mimicking Malignancy on 68 Ga-FAPI-04 PET/CT.

ABSTRACT: We present 2 patients mimicking malignancy with intense gastric 68 Ga-FAPI-04 uptake on PET/CT. Both patients showed low to moderate 18 F-FDG uptake. Histopathology revealed chronic active gastritis. Chronic gastritis may resemble gastric malignancies by showing false-positive 68 Ga-FAPI-04 uptake.

Increased FDG Uptake in Skin Rashes Caused by EGFR Inhibitors.

ABSTRACT: Most patients treated with epidermal growth factor receptor inhibitors develop cutaneous advance effects. The extent and severity of treatment-related skin rashes are associated with good treatment response and prognosis. Herein, we presented increased uptake of the 18F-FDG in skin rashes after treatment with epidermal growth factor receptor inhibitors in 2 patients diagnosed with metastatic colorectal cancer.

Mild 68Ga PSMA-11 Uptake in Incidental Pituitary Adenoma.

A 76-year-old man with metastatic prostate cancer was referred to 68Ga prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) for restaging. A consecutive 18F-fluorodeoxyglucose (FDG) PET/CT was performed due to the history of lung cancer in the left lung treated with stereotactic radiotherapy. Intense 18F-FDG uptake was detected in the pituitary gland despite the mild uptake of 68Ga PSMA. Contrast-enhanced magnetic resonance imaging confirmed pituitary adenoma.

Diagnostic impact of F-FDG PET/CT imaging on the detection of immune-related adverse events in patients treated with immunotherapy

Introduction: Immunotherapy is an effective treatment method for cancer cells with humoral and cellular immune mechanisms of action but triggers an inflammatory response and disrupts standard protective immune tolerance. Early detection of immune-related adverse events (irAEs) on PET/CT is crucial for patient management and subsequent therapy decisions. In this study, we aimed to evaluate the impact of 18F-FDG PET/CT on detecting of irAEs in patients receiving immunotherapy.Patients and methodsForty-six patients with advanced RCC (n: 32), malign melanoma (n: 9), lung cancer (n: 4), and laryngeal carcinoma (n: 1), who underwent 18F-FDG PET/CT imaging for response assessment after immunotherapy, were enrolled in the study. Newly detected findings associated with irAEs on posttreatment PET/CT images were compared with the pretreatment PET/CT, both qualitatively and semi-quantitatively.ResultsTwenty-eight (61%) patients developed irAEs as observed on PET/CT. Enteritis/colitis was the most frequent irAE visualized on PET/CT with 13 patients (28.2%), followed by gastritis (17.3%), thyroiditis (13%), and myositis/arthritis (13%). Hepatitis (6.5%), pneumonitis (6.5%), sarcoid-like reaction (4.3%), and hypophysitis (4.3%) were observed to a lesser extent. The median time between the appearance of irAEs on PET/CT and the initiation of immunotherapy was 4.3 months. There were no significant differences in age, sex, and treatment response status of patients with and without irAEs.Conclusion18F-FDG PET/CT plays a fundamental role in cancer immunotherapy with the potential to show significant irAEs both in the diagnosis and in follow-up of irAEs. IrAEs were present on PET/CT images of more than half of the patients who received immunotherapy in our study. (AU)

18 F-FDG PET/CT in Urethral Metastases From Bladder Cancer.

ABSTRACT: Urethral metastasis of bladder cancer after surgery is rare. We present a 63-year-old man who had surgery for invasive bladder carcinoma and prostate adenocarcinoma 4 years ago and referred for urethral hemorrhage. 18 F-FDG PET/CT was performed for restaging and showed intense linear 18 F-FDG activity in the proximal urethra. The patient underwent urethrectomy, and histopathology determined urethral metastasis.

Comparison of 18F-FDG and 68Ga-FAPI PET/CT in Gastric Kaposi Sarcoma.

ABSTRACT: Herein, we present the results of 18F-FDG PET/CT and 68Ga-FAPI-4 PET/CT of a patient with metastatic Kaposi sarcoma. A 47-year-old man with suspected gastric cancer was referred to 18F-FDG PET/CT for diagnosis and staging. PET/CT detected increased 18F-FDG uptake in metastatic lymphadenopathies and liver lesions. 68Ga-FAPI-4 PET/CT was performed for ongoing clinical trial. Although 68Ga-FAPI-4 PET/CT may be a better alternative than 18F-FDG for the imaging of primary tumoral infiltrations in the stomach, 18F-FDG seems to be a more useful agent for the Kaposi sarcoma in determining the extent of the disease and the localization of metastatic lesions.

Late-Term Findings of Pancreatitis on 68 Ga-PSMA PET/CT in a Patient With Prostate Cancer.

ABSTRACT: The 68 Ga-PSMA PET/CT imaging modality is used to evaluate biochemical recurrence, response to treatment, and staging in prostate cancer. Prostate-specific membrane antigen (PSMA) receptor activation can be seen in benign and malignant diseases as well as in many physiological tissues. Many pitfalls and artifacts have been reported when reporting 68 Ga-PSMA PET/CT. In this case, diffuse moderate PSMA receptor activation in pancreatic tissue due to the previous pancreatitis is presented in 68 Ga-PSMA PET/CT imaging modality that was performed for restaging of prostate cancer.