Metastatic Renal Cell Cancer Treated With Antiangiogenic Therapy Monitoring by 18F-FDG PET/CT.

Renal cell carcinoma (RCC) is resistant to chemotherapy and radiotherapy in most cases, and surgery is the preferred option in patients with local tough advanced disease. Even in metastatic RCC, patient survival has been reported to improve after surgery. Considering the importance of angiogenesis in RCC pathogenesis, new inhibitors of vascular endothelial growth factor pathway show promising results. Imaging monitoring with F-FDG PET/CT may allow selecting the appropriateness and right time to implement these drugs, according to disease outcome.

Therapeutic Algorithm Guided by Sequential 11C-Choline PET/CT in a Patient With Metastatic Castration-Resistant Prostate Cancer.

Antiandrogen therapy alone or combined with radical therapy is the first choice in diagnosis and recurrence of patients with metastatic prostate cancer. However, patients on androgen deprivation frequently show treatment resistance. In recent years, new treatments for metastatic castration-resistant prostate cancer have been developed. Clinical studies with docetaxel have shown its usefulness for first-line therapy, and different therapeutic algorithms with second-line drugs like abiraterone or cabazitaxel have also been proposed. Sequential metabolic study with PET/CT imaging with ¹¹C-choline may be important for assessing the right moment for administration each one of the therapeutic options.

Dual-phase 11C-choline PET/computed tomography in the early evaluation of prostate cancer recurrence.

PURPOSE: The aim of this study was to assess dual-phase 11C-choline PET/computed tomography (CT) for differentiating benign from malignant lesions in patients with biochemical recurrence of prostate cancer. MATERIALS AND METHODS: We prospectively studied 56 patients with prostate cancer treated by surgery (n=22) or radiotherapy (n=34) who had hypermetabolic foci on 11C-choline PET/CT determined for biochemical recurrence (prostate-specific antigen 1.23-9.9 ng/ml). We used the dual-phase technique, calculating the standardized uptake value (SUV) for early (SUVearly) and late (SUVdelay) acquisitions and the difference between the two (SUVvariation) to determine whether tracer uptake remained stable or increased (accumulative pattern) or decreased (washout pattern). We used t-tests to compare mean and receiver operating characteristic curve analysis (SUVearly/SUVdelay/SUVvariation vs. benign/malignant). RESULTS: We identified 106 hypermetabolic foci (34 local, 10 inguinal, 34 infradiaphragmatic, 14 supradiaphragmatic, and 14 in bone). We identified 34 local foci (eight after prostatectomy and 26 after radiotherapy). The eight postsurgical foci had an accumulative pattern and recurrence was confirmed (three histology, five follow-up). Of the 26 postradiotherapy foci, three had a washout pattern and follow-up ruled out recurrence; 23 had an accumulative pattern and recurrence was confirmed (14 histology, nine follow-up). The 10 inguinal foci had a washout pattern and were reactive (three histology, seven follow-up). The 34 infradiaphragmatic foci had an accumulative pattern and were malignant (34 follow-up). Of the 14 supradiaphragmatic foci, the three with a washout pattern were benign (three histology) and the 11 with an accumulative pattern were malignant (11 histology). Of the 14 foci in bone, two had a washout pattern and corresponded with signs of spondyloarthropathy. On the receiver operating characteristic curve analysis, SUVvariation best discriminated benign from malignant lesions [area under the curve (AUC)=0.993], followed by SUVdelay (AUC=0.933) and finally SUVearly (AUC=0.665). CONCLUSION: Dual-phase PET/CT with 11C-choline is technically feasible despite this tracer's short physical half-life and is useful for discriminating benign from malignant lesions. SUVvariation accurately discriminated between benign and malignant lesions.

Detección de infección del electrodo del DAI mediante tomografía por emisión de positrones-tomografía computarizada con 18F-fluorodesoxiglucosa / Detection of ICD Electrode Infection using 18F-fluorodeoxyglucose Positron Emission Tomography-computed Tomography

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Incidental diagnosis of diffuse large B-cell lymphoma by 11C-choline PET/CT in a patient with biochemical recurrence of prostate cancer.

The main indication for C-choline PET/CT in prostate cancer patients is the early localization of biochemical recurrence after radical treatment. However, any C-choline uptake should be assessed in terms of physiological distribution and patterns of tumor spread. Therefore, tracer-avid lesions in unexpected sites should be carefully addressed because the diagnosis of other malignancies has important therapeutic implications. We present a patient with biochemical recurrence of prostate cancer treated with radiotherapy. C-choline PET/CT showed local recurrence and inguinal lymph node uptake. Because of its location beyond typically prostatic lymphatic spread, resection was performed. Histology confirmed a diffuse large B-cell lymphoma.

Influence of subcutaneous administration of rapid-acting insulin in the quality of (18)F-FDG PET/CT studies.

OBJECTIVE: The aim of this study was to develop a protocol for normalizing blood glucose levels in diabetic patients by subcutaneously administering rapid-acting insulin before administering (18)F-fluorodeoxyglucose ((18)F-FDG) without hindering the quality of PET/computed tomography (CT) studies. MATERIALS AND METHODS: The study included 120 patients, who were divided into four groups: Group I: This group comprised 30 diabetic patients with blood glucose levels lower than 160 mg/dl at the time of arrival at our center; in these patients, (18)F-FDG was injected without prior administration of subcutaneous rapid-acting insulin. Group II: This group comprised 30 diabetic patients with blood glucose levels ranging from 168 to 260 mg/dl; in these patients, subcutaneous rapid-acting insulin was administered and then (18)F-FDG was injected when blood glucose levels dropped below 160 mg/dl (30-115 min). Group III: This group included 30 diabetic patients with blood glucose levels ranging from 192 to 324 mg/dl; in these patients, subcutaneous rapid-acting insulin was administered and then (18)F-FDG was injected 4 h later. Blood glucose levels dropped below 160 mg/dl (range, 58-159 mg/dl) in all patients. CONTROL GROUP: This group included 30 nondiabetic patients with normal blood glucose levels (72-104 mg/dl). We calculated the mean standardized uptake value (SUV) of muscle from the maximum SUV in five consecutive axial slices in the proximal middle third of the rectus femoris muscle of the right thigh. RESULTS: The quality of the PET-CT studies was considered suboptimal when muscle uptake was more than 2 SDs greater than the mean muscle uptake in the control group (1.15±0.2). The mean SUV of muscle was as follows: Group I, 1.09 (σ=0,26); group II, 1.98 (σ=0,32); group III, 1.98 (σ=1,13); and control group IV, 1.15 (σ=0,2). The quality of PET-CT studies was considered suboptimal in 18 patients in group II (60%) and in four patients (13%) in group I. The quality was optimal in all studies conducted in group III patients. CONCLUSION: Subcutaneous administration of rapid-acting insulin normalizes blood glucose levels without compromising the quality of PET-CT studies when (18)F-FDG is administered not earlier than 4 h later.

Bone metastases from prostate cancer: 18F-fluoride PET/CT in a patient with discordant bone scintigraphy and 11C-choline PET/CT.

Bone scintigraphy has been used extensively in prostate cancer patients to detect bone involvement. (11)C-choline PET/CT is indicated when a biochemical recurrence is suspected, as this procedure is able to detect local recurrence, lymph-node infiltration, and metastases.In cases where the results of these 2 procedures do not coincide, MRI is then usually performed. (18)F-fluoride may become an alternative to MRI for bone imaging.In our patient series, all bone lesions with (11)C-choline uptake were metastases. (18)F-Fluoride did not increase specificity of (11)C-choline but increased sensitivity of bone scintigraphy. CT helped in the interpretation of osteoarthritis and trauma lesions.