Accuracy and precision assessment for activity quantification in individualized dosimetry of 177Lu-DOTATATE therapy

Background: In order to obtain a reliable 177Lu-DOTATATE therapy dosimetry, it is crucial to acquire accurate and precise activity measurements with the radionuclide calibrator, the SPECT/CT camera, and the NaI(Tl) well counter. The aim of this study was to determine, in a clinical context, the accuracy and the precision of their activity quantification over a range of activities and time. Ninety-three 177Lu sources from the manufacturer were measured in the radionuclide calibrator over 2.5 years to evaluate its calibration accuracy and precision compared to the manufacturer’s value. A NEMA 2012/IEC 2008 phantom was filled with a 177Lu activity concentration sphere-to-background ratio of five. It was acquired with the SPECT/CT camera to determine the reconstruction parameters offering the best compromise between partial volume effect and signal-to-noise ratio. The calibration factor was computed accordingly. The calibration quality was monitored over 2.5 years with 33 phantom acquisitions with activities ranging from 7040 to 0.6 MBq. Home-made sources were used to calibrate the well counter. Its reliability was evaluated with activities ranging from 150 to 0.2 kBq measured 34 times over 2.5 years. Results: For the radionuclide calibrator, median [interquartile range] for the error on activity measurement was −0.99 [1.31] %. The optimal SPECT reconstruction parameters were obtained with 16 iterations, 16 subsets and a 12-mm Gaussian post-filter. The calibration factor was 9.87 cps/MBq with an error of −1.05 [2.12] %. The well counter was calibrated with 31.5 cps/kBq, and the error was evaluated to −12.89 [16.55] %. Conclusions: The accuracy and the precision of activity quantification using dedicated quality control were found to be sufficient for use in dosimetry implemented in clinical routine. The proposed methodology could be implemented in other centres to obtain reproducible 177Lu-based treatment dosimetry.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Моделирование атмосферной колонны установки первичной переработки нефти с целью улучшения качества дизельной фракции

Объектом исследования является атмосферная колонна установки первичной переработки нефти. Целью работы является промежуточное циркуляционное орошение, исследование влияния расходов и температур возвратов промежуточных циркуляционных орошений основной атмосферной колонны на качество и количество получаемой дизельной фракции из основной атмосферной колонны с помощью математической модели действующей установки фракционирования нефти.The object of the study is the atmospheric column of a primary oil refinery. The aim of the work is intermediate circulating irrigation, a study of the influence of the costs and return temperatures of intermediate circulatory irrigation of the main atmospheric column on the quality and quantity of the diesel fraction obtained from the main atmospheric column using the mathematical model of an operating oil fractionation unit

18F-FDG PET/CT for early prediction of response to neoadjuvant lapatinib, trastuzumab, and their combination in HER2-positive breast cancer: results from Neo-ALTTO

Molecular imaging receives increased attention for selecting patients who will benefit from targeted anticancer therapies. Neo-ALTTO (Neoadjuvant Lapatinib and/or Trastuzumab Treatment Optimisation) enrolled 455 women with invasive human epidermal growth factor receptor 2 (HER2)-positive breast cancer and compared rates of pathologic complete response (pCR) to neoadjuvant lapatinib, trastuzumab, and their combination. Each anti-HER2 therapy was given alone for 6 wk, followed by 12 wk of the same therapy plus weekly paclitaxel. The early metabolic effects of the anti-HER2 therapies on the primary tumors and their predictive values for pCR were assessed in a subset of patients. Methods: eighty-six patients underwent (18)F-FDG PET/CT at baseline and weeks 2 and 6 of anti-HER2 treatment. An imaging core laboratory provided central validation, and 2 independent reviewers, masked to assigned treatment arm and clinical outcomes, performed consensus (18)F-FDG PET/CT readings. Maximum standardized uptake value (SUVmax) reductions from baseline were used to measure metabolic response. Results: seventy-seven of the 86 enrolled patients presented an evaluable baseline (18)F-FDG PET/CT scan; of these, 68 and 66 were evaluable at weeks 2 and 6, respectively. Metabolic responses in the primary tumors were evident after 2 wk of targeted therapy and correlated highly with metabolic responses at week 6 (R(2) = 0.81). pCRs were associated with greater SUVmax reductions at both time points. Mean SUVmax reductions for pCR and non-pCR, respectively, were 54.3% versus 32.8% at week 2 (P = 0.02) and 61.5% versus 34.1% at week 6 (P = 0.02). (18)F-FDG PET/CT metabolic response rates at weeks 2 and 6 were 71.6% and 60%, respectively using European Organization for Research and Treatment of Cancer criteria; pCR rates were twice as high for (18)F-FDG PET/CT responders than nonresponders (week 2: 42% vs. 21%, P = 0.12; week 6: 44% vs. 19%, P = 0.05). Conclusion: early metabolic assessment using (18)F-FDG PET/CT can identify patients with an increased likelihood of pCR after neoadjuvant trastuzumab, lapatinib, or their combination when given with chemotherapy

NEOadjuvant therapy monitoring with PET and CT in Esophageal Cancer (NEOPEC-trial)

Contains fulltext : 70883.pdf (publisher's version ) (Open Access)ABSTRACT: BACKGROUND: Surgical resection is the preferred treatment of potentially curable esophageal cancer. To improve long term patient outcome, many institutes apply neoadjuvant chemoradiotherapy. In a large proportion of patients no response to chemoradiotherapy is achieved. These patients suffer from toxic and ineffective neoadjuvant treatment, while appropriate surgical therapy is delayed. For this reason a diagnostic test that allows for accurate prediction of tumor response early during chemoradiotherapy is of crucial importance. CT-scan and endoscopic ultrasound have limited accuracy in predicting histopathologic tumor response. Data suggest that metabolic changes in tumor tissue as measured by FDG-PET predict response better. This study aims to compare FDG-PET and CT-scan for the early prediction of non-response to preoperative chemoradiotherapy in patients with potentially curable esophageal cancer. METHODS/DESIGN: Prognostic accuracy study, embedded in a randomized multicenter Dutch trial comparing neoadjuvant chemoradiotherapy for 5 weeks followed by surgery versus surgery alone for esophageal cancer. This prognostic accuracy study is performed only in the neoadjuvant arm of the randomized trial. In 6 centers, 150 consecutive patients will be included over a 3 year period. FDG-PET and CT-scan will be performed before and 2 weeks after the start of the chemoradiotherapy. All patients complete the 5 weeks regimen of neoadjuvant chemoradiotherapy, regardless the test results. Pathological examination of the surgical resection specimen will be used as reference standard. Responders are defined as patients with < 10% viable residual tumor cells (Mandard-score).Difference in accuracy (area under ROC curve) and negative predictive value between FDG-PET and CT-scan are primary endpoints. Furthermore, an economic evaluation will be performed, comparing survival and costs associated with the use of FDG-PET (or CT-scan) to predict tumor response with survival and costs of neoadjuvant chemoradiotherapy without prediction of response (reference strategy). DISCUSSION: The NEOPEC-trial could be the first sufficiently powered study that helps justify implementation of FDG-PET for response-monitoring in patients with esophageal cancer in clinical practice. TRIAL REGISTRATION: ISRCTN45750457

Optimizing the use of PET with selective internal radiation therapy

SCOPUS: cp.jinfo:eu-repo/semantics/publishe

Role of positron emission tomography in the management of head and neck cancer in the molecular therapy era.

The utility of positron emission tomography-computed tomography has increasingly been studied during the last years. Positron emission tomography-computed tomography offers a holistic approach of cancer diagnosis as it can integrate structural, functional, metabolic, and molecular information of tumour. The technique offers three-dimensional, high-resolution, whole body, and quantitative imaging. 18F-Fluoro-2-deoxy-D-glucose still remains the only tracer widely available. Other tracers have been designed for assessment of proliferation, amino acid uptake, and hypoxia.Journal ArticleReviewSCOPUS: re.jinfo:eu-repo/semantics/publishe

Thyroid cancer: 18F-Fluoro-2-Deoxy-D-Glucose positron emission tomography (an overview)

Thyroid carcinomas are fairly uncommon and include a broad range of disease types: 94% are differentiated thyroid carcinoma (DTC), 5% are medullary thyroid carcinoma (MTC), and the remaining 1% are anaplastic thyroid carcinoma (ATC). DTCs are derived from the follicular epithelial cells and are either papillary thyroid carcinoma or follicular thyroid carcinoma. MTC is a calcitonin and carcinoembryonic antigen (CEA) secreting neuroendocrine tumor of the parafollicular C-cells of the thyroid. ATC is a very aggressive tumor with poor prognosis characterized by extended local invasion and high frequency of distant metastases at the time of initial diagnosis. Positron emission tomography (PET) using 18F-fluoro-2-deoxy-D-glucose (FDG) as the radiotracer depicts cancer sites based on their increased glucose metabolism. The normal thyroid shows low avidity for FDG. The enhanced ability of thyroid cancers to transport and accumulate glucose is the basis for the use of FDG-PET to identify malignant tumors and metastases. More precisely, the increased FDG accumulation is based on an increased expression of glucose transporters (GLUT), together with an increase of hexokinase activity and a decreased activity of phosphatase seen in most types of tumors. The technique is increasingly used in cancer care because the molecular and metabolic mechanisms underlying the FDG uptake are completely independent of associated structural characteristics, resulting in a superior diagnostic specificity, and because metabolic changes precede structural changes, increasing its sensitivity for early disease stages and its potential for early assessment of the post-therapeutic effects. © 2008 Elsevier Inc.SCOPUS: ch.binfo:eu-repo/semantics/publishe