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    18F-FDG PET/CT and 68Ga-FAPI-04 PET/CT Findings of Abdominal Leiomyosarcoma
    (Lippincott Williams & Wilkins, 2021) Guzel, Yunus; Can, Canan; Sogutcu, Nilgun; Gundes, Ebubekir; Gundogan, Cihan
    A 56-year-old woman presented with abdominal pain and vomiting. Her abdominal CT revealed an retroperitoneal mass in the left upper quadrant of the abdomen. F-18-FDG PET/CT performed for metabolic characterization showed low to moderate heterogenous FDG uptake. Ga-68-fibroblast activation protein-specific inhibitor (FAPI)-04 PET/CT performed according to a research carried out in our department showed high heterogenous radiopharmaceutical uptake. The patient was diagnosed with leiomyosarcoma after R0 tumor resection. This case showed that Ga-68-FAPI-04 PET/CT could be a promising radiopharmaceutical in the evaluation of leiomyosarcomas.
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    68GA-FAPI-04 PET/CT Versus 18F-FDG PET/CT in Imaging of Malignant Mixed Germ Cell Testicular Tumor
    (Lippincott Williams & Wilkins, 2023) Kaplan, Ihsan; Can, Canan; Guzel, Yunus; Alabalik, Ulas; Komek, Halil
    F-18-FDG PET/CT imaging was performed for restaging in in a 16-year-old boy who was operated on for right testicular tumor and was diagnosed with malignant mixed germ cell tumor. Mild FDG uptake was observed in 2 nodules in both lungs and retroperitoneal lymph node in the abdomen. Ga-68-FAPI (fibroblast activation protein inhibitor) 04 PET/CT showed moderate uptake of FAPI in lung nodules and retroperitoneal lymph node. In this case, Ga-68-FAPI-04 PET/CT was shown to be superior to F-18-FDG PET/CT in the evaluation of malignant mixed germ cell testicular tumor metastases.
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    68Ga-FAPI-04 PET/CT Versus 18F-FDG PET/CT in Malignant Peritoneal Mesothelioma
    (Lippincott Williams & Wilkins, 2022) Gundogan, Cihan; Guzel, Yunus; Komek, Halil; Etem, Hulya; Kaplan, Ihsan
    [Abstract Not Available]
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    Comparison of 18F-FDG PET/CT and 68Ga-FAPI-04 PET/CT in patients with non-small cell lung cancer
    (Lippincott Williams & Wilkins, 2022) Can, Canan; Kepenek, Ferat; Komek, Halil; Gundogan, Cihan; Kaplan, Ihsan; Tasdemir, Bekir; Guzel, Yunus
    Aim In this study, we aimed to compare the diagnostic accuracy of F-18-fluorodeoxyglucose (F-18-FDG) and Gallium-68 labeled fibroblast activator protein inhibitor (Ga-68-FAPI)-04 PET/CT in the tumor-node-metastasis (TNM) staging of patients with nonsmall cell lung cancer (NSCLC) and investigate whether adenocarcinoma (ADC) and squamous cell cancer (SCC) exhibit different uptake patterns on Ga-68-FAPI-04 PET/CT. Materials and method Twenty-nine patients with a histopathologically-confirmed diagnosis of NSCLC, who had no history of previous radiation therapy or chemotherapy and underwent F-18-FDG PET/CT and Ga-68-FAPI-04 PET/CT imaging between January 2021 and December 2021 were included in this retrospective study. Staging was performed using the 8th edition of the TNM staging system on both F-18-FDG PET/CT and Ga-68-FAPI-04 PET/CT images. Standardized uptake value (SUV)(max) and tumor-to-background ratios (TBR) were calculated on primary lesions and metastases. Results There was no statistically significant difference in primary lesions in terms of SUVmax and TBR values. However, Ga-68-FAPI-04 PET/CT was significantly superior to F-18-FDG PET/CT in terms of the number of lymph nodes and bone metastases revealed. The SUVmax and TBR values of lymph nodes, hepatic lesions and bone lesions were significantly higher on Ga-68-FAPI-04 PET/CT than on F-18-FDG PET/CT. Ga-68-FAPI-04 PET/CT changed the disease stage of three patients (10.9%). The diagnostic accuracy of Ga-68-FAPI-04 PET/CT was 100%, whereas the diagnostic accuracy of F-18-FDG PET/CT was 89.6% (P = 0.250). Conclusion Although Ga-68-FAPI-04 PET/CT detected more lesions and higher diagnostic accuracy than F-18-FDG PET/CT in NSCLC, neither method was statistically superior to each other in terms of diagnostic accuracy in TNM staging.
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    Evaluation of dual time-point fluorodeoxyglucose PET/computed tomography imaging in gastric cancer
    (Lippincott Williams & Wilkins, 2020) Tasdemir, Bekir; Guzel, Yunus; Komek, Halil; Can, Canan
    Background We aimed to evaluate the efficiency of dual time-point fluorodeoxyglucose (FDG) PET/computed tomography (CT) imaging in detecting primary and metastatic lesions in gastric cancer. Methods Between May 2019 and January 2020, 52 patients with gastric carcinoma were prospectively involved in our study. And dual time-point FDG PET/CT imaging performed to the patients. Of detected primary and metastatic lesions, the ones that are better visualized or only appear in delayed imaging were visually identified. Also, maximum standardized uptake value (SUVmax) of the primary and metastatic lesions and the intact liver tissue were measured in early and delayed imaging. Acquired SUVmax values and SUVmax ratios were compared statistically. Results In delayed images, lesions were better visualized in 32 patients (61.5%) and extra lesions were detected in 4 patients (7.7%). SUVmax of primary tumor, SUVmax of liver metastases, SUVmax of lymph node metastases, primary tumor SUVmax/liver SUVmax ratio and lymph node metastasis SUVmax/liver SUVmax ratio were significantly higher in delayed images (P < 0.001, P = 0.022, P < 0.001, P < 0.001, P < 0.001, respectively). However, SUVmax of liver parenchyma was significantly lower in delayed images (P < 0.001). Conclusions There is a visually and statistically significant increase in the number and detectability of lesions seen in delayed images and dual time-point FDG PET/CT imaging seems useful in detecting primary and metastatic lesions in gastric cancer.
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    False-Positive 68Ga-Fibroblast Activation Protein-Specific Inhibitor Uptake of Benign Lymphoid Tissue in a Patient With Breast Cancer
    (Lippincott Williams & Wilkins, 2021) Gundogan, Cihan; Guzel, Yunus; Can, Canan; Alabalik, Ulas; Komek, Halil
    Ga-68-fibroblast activation protein-specific inhibitor (FAPI)-04 PET/CT was performed in a patient with left lower outer quadrant breast cancer who had F-18-FDG PET/CT imaging. Ga-68-FAPI-04 PET/CT showed higher accumulation of radiotracer in primary tumor and axillary lymph nodes than F-18-FDG PET/CT. In addition, focal increased FAPI uptake was observed in another nodular lesion in the lower inner quadrant in the same breast, which was considered malignant. However, Tru-Cut biopsy of this lesion was reported as benign lymphoid tissue. This case showed that all FAPI accumulation in breast tissue should not be interpreted in favor of malignancy; histopathological confirmation is required.
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    Local imaging to interpret tumor size in F18 fluorodeoxyglucose positron emission tomography/CT in lung cancers
    (Assoc Medica Brasileira, 2024) Tuzcu, Sadiye Altun; Kaplan, Ihsan; Ibiloglu, Ibrahim; Uyar, Ali; Guzel, Fatih; Guzel, Yunus; Tasdemir, Bekir
    OBJECTIVE: This study aimed to determine the thoracic and extra-thoracic extension of the disease in patients diagnosed with lung cancer and who had whole-body F18-fluorodeoxyglucose positron emission tomography/CT imaging and to investigate whether there is a relationship between tumor size and extrathoracic spread. METHODS: A total of 308 patients diagnosed with lung cancer were included in this study. These 308 patients were first classified as group 1 (SPN 30 mm>longest lesion diameter >= 10 mm) and group 2 (lung mass (longest lesion diameter >= 30 mm), and then the same patients were classified as group 3 (nodular diameter of <= 20 mm) and group 4 (nodular size of >20 mm). Group 1 was compared with group 2 in terms of extrathoracic metastases. Similarly, group 3 was compared with group 4 in terms of frequency of extrathoracic metastases. F18 fluorodeoxyglucose positron emission tomography/CT examination was used to detect liver, adrenal, bone, and supraclavicular lymph node metastasis, besides extrathoracic metastasis. RESULTS: Liver, bone, and extrathoracic metastasis in group 1 was statistically lower than in group 2 (p<0.001, p<0.01, and p=0.03, respectively). Liver, extrathoracic, adrenal, and bone metastasis in group 3 was statistically lower than that in group 4 (p<0.001, p=0.01, and p=0.04, p<0.01, respectively). The extrathoracic extension was observed in only one patient in group 3. In addition, liver, adrenal, and bone metastases were not observed in group 3 patients. CONCLUSION: Positron emission tomography/CT may be more appropriate for cases with a nodule diameter of <= 20 mm. Performing local imaging in patients with a nodule diameter of <= 20 mm could reduce radiation exposure and save radiopharmaceuticals used in positron emission tomography/CT imaging.
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    Nivolumab-Related Dry Mouth and Dry Eye: Cross-Sectional Study
    (Taylor & Francis Inc, 2021) Yildirim, Ozgen Ahmet; Poyraz, Kerem; Erdur, Erkan; Can, Canan; Gundogan, Cihan; Guzel, Yunus; Etem, Hulya
    To evaluate ICIs related dry eye and dry mouth in nivolumab therapy, 24 patients receiving nivolumab (group 1), 30 patients in remission without treatment for 6 months (group 2), 30 healthy participants (group 3) were cross-sectionally examined. Schirmer's 1, 2, TSH blood tests, serological analysis, salivary flow scintigraphy and minor-salivary gland biopsy were performed. Schirmer's tests were performed with anesthetic (1) and without anesthetic (2). Schirmer's scores were lower in group 1 with more frequent reduced tear production (p < 0.001). TSH levels negatively correlated with Schirmer's scores. Functional insufficiency was detected by salivary flow scintigraphy in 7 out of 10 patients with Schirmer's test positivity. In Schirmer's positive patients, lymphocytic sialadenitis was confirmed in 4 patients (focus score > 1) and CD4 T lymphocyte precipitation was observed in 6 patients. Nivolumab therapy may be associated with ICIs related immune sicca.
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    Perirenal Infiltration of Signet Ring Cell Colon Carcinoma Shown by 68Ga-FAPI PET/CT
    (Lippincott Williams & Wilkins, 2022) Guzel, Yunus; Kaplan, Ihsan; Kepenek, Ferat; Sogutcu, Nilgun; Komek, Halil
    A soft tissue lesion surrounding the left kidney was detected in F-18-FDG PET/CT performed with suspicion of recurrence in a patient who was operated for descending colon cancer and showed mild FDG uptake. Intense fibroblast activation protein-specific inhibitor (FAPI) uptake in the perirenal soft tissue was observed in Ga-68-FAPI-04 PET/CT. Tru-cut biopsy of the left perirenal lesion revealed signet ring cell colon carcinoma metastasis. This case demonstrated that Ga-68-FAPI-04 PET/CT could be a promising radiopharmaceutical for the evaluation of signet ring cell colon carcinomas.
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    Role of 68Ga-PSMA PET/CT parameters in treatment evaluation and survival prediction in prostate cancer patients compared with biochemical response assessment
    (Hellenic Soc Nuclear Medicine, 2021) Can, Canan; Gundogan, Cihan; Yildirim, Ozgen Ahmet; Poyraz, Kerem; Guzel, Yunus; Komek, Halil
    Objective: In this study, we aimed to evaluate the concordance of biochemical treatment response with gallium-68-prostate specific membrane antigen (Ga-68-PSMA) positron emission tomography/computed tomography (PET/CT) treatment response in prostate cancer (PCa) and investigate their prognostic effects on survival. Materials and Methods: One hundred and fifty-one patients with PCa, who underwent Ga-68-PSMA PET/CT imaging in our clinic between May 2016 and December 2019, were on treatment, and had pre-treatment and post-treatment imaging studies were included in our study. The treatment patients received and prostate-specific antigen (PSA) levels at the time of PET/CT imaging were recorded. Pre- and post-treatment whole-body metabolic tumor volume (MTVw), whole-body total lesion PSMA (TLPw), percent change in PSA (Delta PSA), Delta MTV, and Delta TLP values were calculated in all patients. Survival time of all patients was measured from the time of initial PET imaging. Results: Median age of patients included in our study was 71 years (range: 51-88). When Delta PSA response and Delta TLP response were evaluated together (r:0.71, P<0.001 and k:0.541, P<0.001), statistically significance strong correlation and moderate concordance was observed. Delta PSA response and Delta MTV treatment response had statistically significant moderate correlation and moderate concordance (r: 0.66, P<0.01 and k: 0.454, P<0.001, significantly). Between Delta PSA response and Delta TLP and Delta MTV response had stronger correlation and higher concordance when PSA levels were above 10. Multivariate analyses using multiple Cox regression analysis revealed MTVw1 and Delta MTV parameters to be independent prognostic factors for mortality (P:0.003 and P:0.001, respectively). Conclusion: We observed that biochemical response and whole-body volumetric Ga-68-PSMA PET/CT parameter response showed correlation and concordance in all groups with PCa, which was more significant when PSA level was >= 10ng/mL. MTVw1 and Delta MTV parameters obtained via Ga-68-PSMA PET/CT were independent prognostic factors for mortality in Pca. Gallium-68-PSMA PET/CT is a valuable imaging technique for diagnostic purposes as well as follow-up and prognostic evaluation.
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    Role of volumetric parameters obtained from 68 Ga-PSMA PET/CT and 18F-FDG PET/CT in predicting overall survival in patients with mCRPC receiving taxane therapy
    (Springer, 2023) Guzel, Yunus; Komek, Halil; Can, Canan; Kaplan, Ihsan; Akdeniz, Nadiye; Kepenek, Ferat; Gundogan, Cihan
    ObjectiveThe aim of this study was to determine the prognostic role of volumetric parameters and Pro-PET scores obtained from (68) Ga-prostate-specific membrane antigen (PSMA) PET/CT and F-18-FDG PET/CT in patients with metastatic castration-resistant prostate cancer (mCRPC) receiving taxane therapy.Materials and methodsThe study included 71 patients who underwent simultaneous PSMA and F-18-FDG PET/CT imaging between January 2019 and January 2022, had a Pro-PET score of 3-5 and had received taxane therapy after imaging. F-18-FDG tumor volume (TV-F) and PSMA tumor volume (TV-P) values of the lesions and total lesion glycolysis (TL-G) and total lesion PSMA (TL-P) values of the lesions were calculated on both imaging studies and the effects of these parameters on overall survival (OS) were investigated.ResultsThe median age of the patients included herein was 71 years (56-89) and the median prostate-specific antigen (PSA) level was 16.4 (0.01-1852 ng/dL). According to the Kaplan-Meier survival analysis, TTV-P >= 78.5, TTL-P >= 278.8, TTV-F >= 94.98, TTL-G >= 458.3, TTV-P + F >= 195.45, TTL-G + P >= 855.78, lymph node (L)TV-FDG >= 3.4, LFDG-SUVmax >= 3.2, LFDG-SUVmean >= 2.25, LFDG-SUVpeak >= 2.55, and bone (B)TV-F >= 51.15 values were found to be prognostic factors in predicting short OS. Multivariate Cox regression analysis showed that a Vscore >= 3 (95% confidence interval [CI]: 7.069-98.251, p < 0.001) and TTL-G + P >= 855.78 (95% CI: 4.878-1037.860, p = 0.006) were found to be independent prognostic factors in predicting short OS.ConclusionVolumetric parameters and Pro-PET scores obtained from (68) Ga-PSMA PET/CT and F-18-FDG PET/CT imaging have been shown to have an impact on OS in patients with mCRPC receiving taxane therapy.
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    Roles of metabolic tumor volume and total lesion glycolysis on 18F-FDG PET/CT, CA19-9 levels, and complete blood parameters in predicting survival in patients with unresectable or metastatic pancreatic cancer
    (Edizioni Luigi Pozzi, 2022) Erdur, Erkan; Guzel, Yunus; Yildirim, Ozgen Ahmet; Poyraz, Kerem; Yildirim, Mehmet Serdar; Kaplan, Ilsan
    AIM: In this study, we aimed to investigate the roles of volume based F-18-FDG PET/CT parameters, CA19-9 levels, and complete blood count parameters in predicting survival in patients with unresectable and/or metastatic pancreatic ductal adenocarcinoma. MATERIALS AND METHOD: Fifty-seven pancreatic cancer patients who were followed in University of Health Sciences Gazi Yasargil Training and Research Hospital between January 2017 and June 2020, declined surgical treatment and/or radiation therapy or had medically inoperable, unresectable, or metastatic disease, and received chemotherapy were included in the study. F-18-FDG PET/CT images of patients were evaluated and calculated metabolic tumor volume (MTV) and total lesion glycolysis (TLG) parameters were compared with CA19-9 levels and complete blood count parameters. Patients were assessed in two groups as survivors and non-survivors. RESULTS: Total MTV and total TLG on F-18-FDG PET/CT were significantly higher among non-survivors than survivors (p: 0.023 and 0.034, respectively). Multivariate Cox regression analysis revealed that TLG higher than 46 g/ml.cm(3), MTV higher than 11.02 cm(3) (OR 0.987, 95%CI 0.976-0.999, p:0.029 and OR 0.246, 95%CI 0.089-0.685, p: 0.007, respectively) and elevated MPV (OR:0.785, 95% CI 0,574-0.976, p:0.042) were independent prognostic factors for predicting mortality. CONCLUSION: TLG >46 g/ml.cm(3) and MTV >11.02 cm(3) in F-18-FDG PET/CT and elevated MPV in complete blood count are independent prognostic factors for predicting mortality in patients with unresectable or metastatic pancreatic cancer who are treated with chemotherapy.
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    Superiority of 18F-FDG PET/CT to 68GA-FAPI PET/CT in Adrenocortical Tumor Imaging
    (Lippincott Williams & Wilkins, 2023) Kaplan, Ihsan; Can, Canan; Kepenek, Ferat; Ibiloglu, Ibrahim; Guzel, Yunus
    F-18-FDG PET/CT was performed to evaluate the response to treatment in a 62-year-old female patient who was operated for adrenocortical carcinoma. High FDG uptake was observed in recurrent lesion in the left adrenal gland site and metastatic lesions. In the Ga-68-FAPI-04 PET/CT study, low FAPI uptake was observed in both recurrences and metastases. In this case, we demonstrated the superiority of F-18-FDG PET/CT over Ga-68-FAPI-04 PET/CT in the evaluation of adrenocortical carcinoma.