F-FDG PET/CT and radiolabeled leucocyte scintigraphy single-photon emission computed tomography carry high performance in the diagnostic of LVAD infections. F-FDG PET/CT shows significantly higher sensitivity and could be proposed as first-line nuclear medicine procedure.
The human Matrix MetalloProtease-9 (hMMP-9) is overexpressed in tumors where it promotes the release of cancer cells thus contributing to tumor metastasis. We raised aptamers against hMMP-9, which constitutes a validated marker of malignant tumors, in order to design probes for imaging tumors in human beings. A chemically modified RNA aptamer (F3B), fully resistant to nucleases was previously described. This compound was subsequently used for the preparation of F3B-Cy5, F3B-S-acetylmercaptoacetyltriglycine (MAG) and F3B-DOTA. The binding properties of these derivatives were determined by surface plasmon resonance and electrophoretic mobility shift assay. Optical fluorescence imaging confirmed the binding to hMMP-9 in A375 melanoma bearing mice. Quantitative biodistribution studies were performed at 30 min, 1h and 2 h post injection of 99mTc-MAG-aptamer and 111In-DOTA-F3B. 99mTc radiolabeled aptamer specifically detected hMMP-9 in A375 melanoma tumors but accumulation in digestive tract was very high. Following i.v. injection of 111In-DOTA-F3B, high level of radioactivity was observed in kidneys and bladder but digestive tract uptake was very limited. Tumor uptake was significantly (student t test, p<0.05) higher for 111In-DOTA-F3B with 2.0%ID/g than for the 111In-DOTA-control oligonucleotide (0.7%ID/g) with tumor to muscle ratio of 4.0. Such difference in tumor accumulation has been confirmed by ex vivo scintigraphic images performed at 1h post injection and by autoradiography, which revealed the overexpression of hMMP-9 in sections of human melanomas. These results demonstrate that F3B aptamer is of interest for detecting hMMP-9 in melanoma tumor.
WHAT THIS PAPER ADDS This study is the second and the largest to compare 18 F-fluoro-D-glucose (FDG) positron emission tomography/ computed tomography (PET/CT) and white blood cell scan in the diagnosis of prosthetic vascular graft infections (PVGIs). The white blood cell scan was more accurate than 18 F-FDG PET/CT. Moreover, there was only one false negative 18 F-FDG PET-CT result under antibiotic therapy. Nuclear imaging results should be included in the diagnostic criteria for prosthetic vascular graft infections. Computed tomography angiography still remains the first radiological examination to perform when there is suspicion of PVGI. A white blood cell scan should be considered for patients with a suspicion of prosthetic vascular graft infection and negative or equivocal computed tomography angiography results. If a white blood cell scan is not readily available, 18 F-FDG PET/CT can be performed. If the result is negative, prosthetic vascular graft infections can be ruled out thanks to a good negative predictive value. However, a positive result should be interpreted with caution, especially for thrombosed grafts. Objectives: Prosthetic vascular graft infections (PVGIs) are associated with high mortality rates. To improve treatment outcome, an early and definite diagnosis is critical, and current diagnostic criteria are often insufficient. The accuracy of 2-deoxy-2-[fluorine-18]-fluoro-D-glucose positron emission tomography integrated with computed tomography (18 F-FDG PET/CT) and white blood cell (WBC) scan for the diagnosis of PVGI were compared. Methods: A retrospective single centre study was conducted on patients undergoing WBC scan and 18 F-FDG PET/ CT for a suspected PVGI between
Purpose
Selective internal radiotherapy with 90Y microspheres is widely used for the treatment of patients with liver cancer. A dosimetric analysis using the dosimetry software Simplicit90y (Boston Scientific, Natick, MA) was conducted to define doses to the tumor and healthy liver, and to determine a threshold tumor dose that could predict progression-free survival.
Methods
Patients experiencing hepatocellular carcinoma and treated with 90Y-labeled resin microspheres were included in a retrospective study. The time-to-progression of the target lesions (TTPLs) and overall survival (OS) were evaluated using Kaplan-Meier tests, and this comparison was based on a log-rank test.
Results
Twenty-four procedures for patients with portal vein thrombosis were realized. Median follow-up was 16 months. A threshold tumor dose of 125 Gy was determined with a sensitivity of 89% and a specificity of 100%. For patients with a tumor dose of less than 125 Gy, the median OS was 7.5 months (95% confidence interval [CI], 5–14 months) and the TTPL was 3 months (95% CI, 2–6 months) versus 33 months (95% CI, 22–39 months) and 23 months (95% CI, 7–38 months), respectively, for those with a tumor dose of 125 Gy or more (P = 0.002 and P = 0.0004).
Conclusions
Personalized dosimetry based on 99mTc-MAA SPECT/CT is predictive of TTPL and OS in patients with hepatocellular carcinoma. Customized dosimetry software is essential to optimize treatment planning.
Background
Transarterial radioembolization (TARE) is widely used for the treatment of hepatocellular carcinoma (HCC), but early treatment response can be very difficult to assess. The aim was to evaluate 18F-fluorocholine PET/computed tomography (CT) to assess the treatment response in patients with intermediate or locally advanced HCC.
Methods
Between March 2019 and July 2020, nine HCC patients treated with TARE, who underwent PET/CT at baseline and 1 month after treatment, were enrolled. The maximum, mean (SUVmean), and peak (SUVpeak) standardized uptake value (SUV), SUV normalized by lean body mass (SUL), and total lesion glycolysis (TLG) were measured. Statistical analysis used the Mann–Whitney test to evaluate the differences in parameters between responders (partial and complete response) and nonresponders (stable or progressive disease) at the 6-month follow-up, according to the modified Response Evaluation Criteria in Solid Tumors.
Results
Three patients were nonresponders (progressive disease and stable disease) and six were responders. Delta SUVmean, delta SUL, and delta TLG could predict an early response (P = 0.02, P = 0.04, and P = 0.02, respectively). None of the pre-therapeutic parameters were correlated with the response. Post-therapeutic SUL, SUVmean, TLG, and SUVpeak were also predictive of the response.
Conclusions
Our preliminary results showed that changes in certain metabolic parameters (from baseline PET to 1-month PET) are predictive of the response to TARE in HCC (Delta SUVmean, delta TLG, and delta SUL). The absence of post-treatment inflammation could lead to a better prediction than MRI evaluation. This study suggests that 1-month 18F-choline PET/CT could modify the clinical management predicting responders.
Video Abstract: http://links.lww.com/NMC/A193
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