A Comprehensive Analysis of Volumetric 68Ga-PSMA PET/CT Parameters, Clinical and Histopathologic Features: Evaluation of the Predictive Role.

Objectives: To evaluate the relationships between volumetric 68Ga-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) parameters, Gleason score (GS), prostate-specific antigen (PSA) levels, histopathological data, and metastatic status in newly diagnosed prostate cancer (PCa) patients and to assess the predictive factors for progression despite treatment. Methods: A total of 78 newly diagnosed patients with PCa who had 68Ga-PSMA PET/CT scans were included. Clinical parameters, histopathological data, and metastatic status were documented, and volumetric parameters of primary prostate lesions were measured. All obtained data were compared statistically. Results: Primary prostate tumor maximum standardized uptake value (SUVmax) and GS were significantly related to serum PSA levels (p<0.05). PSA levels and SUVmax values were significantly higher in patients with lymph node metastases than in those without. GS was found to be significantly increased in metastatic patients. PSMA-derived tumor volume (PSMA-TV) and total lesion PSMA of the primary lesion had a significant relationship with PSA value, GS, and regional lymph node metastases. Receiver operating characteristic analysis, conducted in patients with metastatic and localized disease, identified the cutoff value for SUVmax as 10.85. According to the results of the logistic regression analysis, PSMA-TV was found to be a predictive factor for progression despite treatment. Conclusion: 68Ga-PSMA PET/CT remains an invaluable imaging modality that should be considered first in PCa staging because of its superior compatibility with clinical and histopathologic data. The importance of this method goes beyond diagnostic accuracy; it also extends into the predictive domain, where the PSMA-TV value of primary prostate lesions is a potential predictor of treatment efficacy. This information is valuable for personalizing patient treatment, improving prognostic accuracy, and predicting clinical outcomes.

EFFECTIVE HALF-LIFE, EXCRETION AND RADIATION EXPOSURE OF 177LU-PSMA.

The study aims to evaluate the radiation safety conditions by detecting the patient's urine excretion rate, calculating the effective half-life, and determining the retention of 177Lu-PSMA in the body. Urine samples of patients were collected for 24 hours (6, 12, 18, and 24 hours) following the infusion, excretion rate and retention of 177Lu-PSMA in the body of patients were calculated. The measurements of dose rate were performed. Effective half-life calculated from dose rate measurements was found as 18.5 ± 11 h within the first 24 h and 48.1 ± 22.8 h between 24 and 72 h. Excreted activity in urine was found as 33.8 ± 20.7, 40.4 ± 20.3, 46.1 ± 22.4, and 53.3 ± 21.5% of total doses at 6, 12, 18, and 24 h after administration, respectively. External dose rates for 4 h and 24 h were 24.51 µSv/h, 16.14 µSv/h, respectively. Our results showed that 177Lu-PSMA treatment was suitable for outpatient treatment in terms of radiation safety.

Inguinoscrotal Bladder Hernia Mimicking Testicle Tumor.

Bladder hernias usually begin asymptomatically and are discovered incidentally at the time of discovery. Preoperative diagnosis of bladder hernias is important to reduce the risk of bladder injury during surgery. Although F-18 FDG PET/CT is applied for oncological purposes, benign conditions should also be taken into account when evaluating the implants. In this article, a case of bladder hernia, which can be confused with pathological cancer involvement, with the diagnosis of F-18 FDG PET/CT performed in a 73-year-old male patient with renal cell carcinoma is presented.

The effect of sodium iodide symporter protein on ablation success in patients with differentiated thyroid cancer.

OBJECTIVE: This study aimed to investigate immunohistochemical staining of sodium iodide symporter (NIS) and its effect on response to I-131 therapy in differentiated thyroid carcinoma patients. METHODS: We evaluated NIS expression, the intracellular distribution of NIS, iodine-131 uptake in residual tissues on post-ablation I-131 whole body scan, and the ablation status after 100 mCi I-131 therapy. We also investigated NIS expression and localization in tumoral paraffin-embedded tissues. RESULTS: In this retrospective study, 35 patients (mean age 44.17 ± 12.9 years, 27 female, 8 male) were studied. Twenty-one of these patients responded to radioiodine therapy, and 14 did not. NIS expression and iodine-131 uptake in residual tissues post-ablation I-131 whole body scan were not statistically significant. When we compared the patients who responded to radioiodine therapy and the poor responder group, NIS expression and iodine-131 uptake in residual tissues did not demonstrate statistically significant difference [(p = 0.308) (p = 0.985) respectively]. 47.6% of the patients in the successful ablation group and 85.7% in the unsuccessful ablation group had intracellular NIS immunostaining. The difference was not statistically significant (p = 0.139). 52.4% of the patients in the successful ablation group and 7% in the unsuccessful ablation group had NIS immunostaining at the basolateral membrane. The difference was statistically significant (p < 0.05). CONCLUSIONS: In conclusion, we did not find any significant difference between successful and unsuccessful ablation groups in terms of NIS expression; however, we concluded that the intracellular (cytoplasmic) localization of NIS is one of the leading causes of ablation failure regardless of NIS expression in DTC patients.

Contribution of Open Mouth Technique in 18F-FDG PET/CT Imaging in Patients with Malignant Lip Neoplasm.

Objectives: 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) plays an important role in evaluating head and neck cancers. However, localization and size evaluation in this region can be rough due to the multitude of the anatomic structures and physiologic uptakes. The aim of this study was to evaluate malignant lip lesions with the contribution of open mouth (OM) imaging technique at PET/CT. Methods: Fifty-six patients with malignant lip neoplasm underwent 18F-FDG PET/CT imaging. Each patient was imaged twice as whole-body PET/CT with routine closed mouth (CM) position; and OM head and neck image, standardized with a special device. Lesion maximum standard uptake value (SUVmax), localization, size, and involvement of lymph nodes were evaluated. Results: Lesion localization was correctly detected in 100% of the OM images. Lesion size in PET/CT was compared with clinical, radiological (magnetic resonance imaging and CT) and/or histopathological results and the size measurement was coherent at 47.1% and 95.6% for CM and OM images, respectively. It was observed that OM acquisition did not contribute additionally in detecting regional lymph node metastasis. Forty-one PET/CT scans with CT artifacts due to dental amalgams were evaluated and 46.3% dimensional and 53.7% localization errors were detected in the CM position. There was no statistically significant difference between OM and CM SUVmax (p>0.05). Conclusion: We concluded that additional OM head and neck imaging is useful and necessary to accurately determine the localization and size of the tumor, thus enhancing the value of PET/CT in staging, treatment response assessment, and restaging of patients with malignant lip cancer with or without dental amalgam.

Unexpected Metastatic Localizations of Prostate Cancer Determined by 68Ga PSMA PET/CT: Series of Four Cases.

Prostate-specific membrane antigen (PSMA) is a transmembrane protein with overexpression in most prostate cancer cells. Gallium-68-(68Ga) PSMA positron emission tomography/computed tomography (PET/CT) imaging is a game-changer in the management of prostate cancer. 68Ga PSMA PET/CT scan is advanced and a promising radioligand has high sensitivity in determining lesions of prostate cancer with a high tumor to background ratio. The most common areas of metastasis are the bone and pelvic lymph nodes. The prognosis of prostate cancer is mainly determined by the status of metastases. The presence and the localization of metastases affects treatment planning. In our cases, we presented some examples of uncommon sites of metastases such as the brain, adrenal glands, penis and orbit. Improvements in imaging techniques, such as 68Ga PSMA PET/CT have led to the possibility to make more determi nation of rare metastase sites in prostate cancer patients.

Somatostatin Receptor Scintigraphy Findings in a Patient with Metastatic Gastrinoma and MEN 1 Syndrome.

UNLABELLED: Liver metastases from neuroendocrine tumours frequently occur and significantly worsen their prognosis. Somatostatin receptor scintigraphy (SRS) is a valuable method for the detection of somatostatin receptor-positive lesions like gastrinoma. In this case report, the importance of SRS to localize the primary tumor and the spread of disease is emphasized in a patient with neuroendocrine liver metastases. A 45-year-old man was admitted to hospital with multiple liver metastasis of neuroendocrine carcinoma. Somatostatin receptor scintigraphy showed multiple intense radiotracer uptakes in the liver and a focal tracer uptake at the right side of the upper abdominal region corresponding to duodenum or pancreas. Elevated serum gastrin levels confirmed the gastrinoma diagnosis. CONFLICT OF INTEREST: None declared.