Recent years have seen the start of treatment of metastatic castration-resistant prostate cancer with prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (PRLT), especially 177 Lu-PSMA-617. However, PRLT has side effects on the salivary glands that limit the safety of the treatment. The current study aimed to show the effect of external cooling with ice packs on 177 Lu-PSMA-617 uptake by the parotid glands (PGs). Methods:The study included 19 patients (mean age, 72.9 y) with metastatic castration-resistant prostate cancer who had been referred for the first time for 177 Lu-PSMA-617 treatment and underwent pretreatment 68 Ga-PSMA-11 PET/CT. Before the initiation of PRLT, the SUV max and SUV mean of the right and left PGs were measured on 68 Ga-PSMA PET/CT. Frozen ice packs were then affixed over the right PG of each patient for approximately 5 h; 1 h after they were affixed, PRLT was administered. At 4 h after PRLT, head-and-neck SPECT/CT was performed, and at both 4 and 24 h after PRLT, whole-body planar scintigraphy was performed. Regions and volumes of interest were applied for the right and left PGs, and the counts and volumes were determined. Results: Before PRLT, 68 Ga-PSMA-11 PET/CT showed no significant difference in SUV max or SUV mean between the right and left PGs (P . 0.05). At 4 and 24 h after PRLT, planar imaging showed no significant difference in counts between the cooled and noncooled PGs (P . 0.05). Furthermore, at 4 h after PRLT, SPECT/CT showed no significant difference in counts or volumes between the cooled and noncooled PGs (P . 0.05). Conclusion: External cooling does not reduce uptake of 177 Lu-PSMA-617 by the PGs.

Kolorektal kanserde KRAS mutasyonu ve tümörün lokalizasyonu ile ilişkili prognostik etki tartışmalı bir konudur. Bu nedenle 18 F-floro-2deoksi-glukoz pozitron emisyon tomografi/bilgisayarlı tomografi ( 18 F-FDG PET/BT) görüntülemede FDG tutulum paterni ile kolon kanseri tanısı almış hastalarda KRAS mutasyonu ve tümör lokalizasyonu arasındaki ilişkiyi değerlendirdik. Bu üç faktörün prognoz ve sağkalım üzerindeki etkileri değerlendirildi. Yöntem: Kolorektal kanser tanılı 83 hasta retrospektif olarak bu çalışmaya dahil edildi. Tedavi öncesi evreleme için 18 F-FDG PET/BT çalışması yapıldı. Primer tümöre ait ortalama standart tutulum değeri (SUV maks ) ve sağkalım verileri gruplar arasında karşılaştırıldı. KRAS mutasyonları, parafine ÖzObjective: Prognostic effect of KRAS mutation and side of tumor in colorectal cancer is a highly controversial subject. Therefore, we evaluated the association between FDG uptake pattern in 18 F-fluoro-2-deoxy-glucose positron emission tomography/computed tomography ( 18 F-FDG PET/ CT) imaging and KRAS mutation and tumor localization in patients with a diagnosis of colon cancer and assessed the effects of these three factors on prognosis and survival. Methods: Eighty-three patients with colorectal cancer were retrospectively included in this study. 18 F-FDG PET/CT study was performed for pretreatment staging. The maximum standardized uptake value (SUV max ) of the primary tumor and survival data of patients were compared between groups. KRAS mutations were detected with the help of real-time Polymerase Chain Reaction technique through genomic DNA extracted from paraffin-embedded tumor tissue blocks. Tumor lesions with potential KRAS mutations were classified as mutant KRAS and wild type. Results: Twenty five patients were female while 58 were male. The mean age of the patients was 59.8±11.3 years. Mean follow-up was 35.5±18.9 months. Primary tumor was localized in the left colon in 83.1% of patients and in the right colon in 16.9%. KRAS mutation was detected in 54.2% (n=45) of patients. Mean SUV max of patients with primary tumor was estimated to be 21.1±9.1 (range= 6.0-47.5). Mean tumor SUV max of patients with a KRAS mutation (24.0±9.0) was found to be significantly higher than those without KRAS mutation (17.7±8.2) (p=0.001). Mean survival was significantly shorter in patients with locoregional nodal metastasis than in patients without locoregional nodal metastasis as well as in patients with distant nodal metastasis than in patients without distant nodal metastasis and in patients with organ metastasis in initial PET/ CT than in patients without organ metastasis. Also, mean survival was nearly statistically-significantly shorter in patients with tumors located in left colon (34.2±19.4) than in right colon (43.2±14.6) (p=0.059). However, we found no significant impact of KRAS mutation on survival. Conclusion:In our study, we found that tumor localization had no significant effect on prognosis in patients with colon cancer. On the other hand, FDG uptake was observed to be higher in th...

Objectives: This study aimed to compare the metabolic parameters obtained from 18 fluorine-fluorodeoxyglucose ( 18 F-FDG) positron emission tomography/computed tomography (PET/CT) and gallium-68 ( 68 Ga)-prostate-specific membrane antigen (PSMA) PET/CT and investigate the relationship between serum alpha-fetoprotein and PET scan parameters in patients with hepatocellular carcinoma. Methods: Fourteen patients were recruited after dynamic magnetic resonance imaging (MRI) of the upper abdomen, and 18 F-FDG and 68 Ga-PSMA PET/CT imaging studies were conducted. Regions of interest (ROIs) were drawn from lesion-free liver tissue, abdominal aorta (A), and right medial gluteal muscle (G) for the background activity. Maximum standard uptake value (SUV max ) of these regions were compared with the SUV max of primary tumor (T). Results: On visual assessment, five patients (36%) experienced low 18 F-FDG uptake in the primary lesion, three patients (21%) experienced moderate uptake, and six patients (43%) experienced high uptake. However, only one patient (7%) showed low 68 Ga-PSMA uptake, two patients (14%) showed moderate uptake, and 11 patients (79%) showed high uptake. Four patients with a low 18 F-FDG uptake showed high 68 Ga-PSMA uptake, while one patient exhibited low uptake with both 18 F-FDG and 68 Ga-PSMA. The number of lesions on 68 Ga-PSMA PET/CT and MRI was significantly higher than 18 F-FDG PET/CT (p=0.042 and 0.026, respectively). T/A and T/G values were significantly higher in 68 Ga-PSMA than 18 F-FDG (p=0.002 and 0.002, respectively). Conclusion: 68 Ga-PSMA PET/CT is superior to 18 F-FDG PET/CT in the staging of hepatocellular carcinoma. High 68 Ga-PSMA uptake could be promising for PSMA-targeted radionuclide treatments.

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