Process – property relationship control during magnesium sheet manufacturing is demanding due to the complexity of involved physical parameters and the sensitivity of the system to small changes. ...Here, data science might help to extract crucial information on interdependencies between processing parameters and sheet quality. In this paper we suggest a dedicated machine learning framework, which enables the possibility of correlating material property determining concepts such as pole figure to processing parameters, namely temperature and deformation degree without knowledge on prior dependencies of physical variables. Despite the impacts that using a relatively small data set can have, for Mg-AZ31 alloy we show that some projections of crystallographic texture can be reliably predicted from mechanical measurement data set. In general, the framework is useful for those processing parameters, which conventionally can be represented by a mathematical basis in the context of interpolation. In the future with access to more data it is proposed that applying our approach might allow predicting and controlling in-situ the rolling process route.
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•Process-structure-property correlation for AZ31 based on machine learning is realized.•Machine learning framework to be applied for process-property relation is proposed.•Approach for intelligent rolling process is suggested.
Molecular Imaging of Prostate Cancer Wibmer, Andreas G; Burger, Irene A; Sala, Evis ...
Radiographics,
01/2016, Letnik:
36, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Prostate cancer is the most common noncutaneous malignancy among men in the Western world. The natural history and clinical course of prostate cancer are markedly diverse, ranging from small indolent ...intraprostatic lesions to highly aggressive disseminated disease. An understanding of this biologic heterogeneity is considered a necessary requisite in the quest for the adoption of precise and personalized management strategies. Molecular imaging offers the potential for noninvasive assessment of the biologic interactions underpinning prostate carcinogenesis. Currently, numerous molecular imaging probes are in clinical use or undergoing preclinical or clinical evaluation. These probes can be divided into those that image increased cell metabolism, those that target prostate cancer-specific membrane proteins and receptor molecules, and those that bind to the bone matrix adjacent to metastases to bone. The increased metabolism and vascular changes in prostate cancer cells can be evaluated with radiolabeled analogs of choline, acetate, glucose, amino acids, and nucleotides. The androgen receptor, prostate-specific membrane antigen, and gastrin-releasing peptide receptor (ie, bombesin) are overexpressed in prostate cancer and can be targeted by specific radiolabeled imaging probes. Because metastatic prostate cancer cells induce osteoblastic signaling pathways of adjacent bone tissue, bone-seeking radiotracers are sensitive tools for the detection of metastases to bone. Knowledge about the underlying biologic processes responsible for the phenotypes associated with the different stages of prostate cancer allows an appropriate choice of methods and helps avoid pitfalls.
Prostate-specific membrane antigen (PSMA) radioligand therapy (RLT) has shown encouraging results for treatment of metastatic castration-resistant prostate cancer (mCRPC) in the prospective, ...multicenter, randomized phase II TheraP study. The inclusion criteria for that study comprised a pretherapeutic
Ga-PSMA-11 PET scan showing sufficient tumor uptake using a predefined threshold and the absence of
F-FDG-positive, PSMA ligand-negative tumor lesions. However, the prognostic value of these PET-based inclusion criteria remains unclear. Therefore, we evaluated the outcome of mCRPC patients treated with PSMA RLT using TheraP as well as other TheraP-based PET inclusion criteria.
First, patients were dichotomized into 2 groups whose PSMA PET scans did (TheraP contrast-enhanced PSMA cePSMA PET-positive) or did not (TheraP cePSMA PET-negative) fulfill the inclusion criteria of TheraP. Notably, unlike in TheraP,
F-FDG PET was not performed on our patients. Prostate-specific antigen (PSA) response (PSA decline ≥ 50% from baseline), PSA progression-free survival, and overall survival (OS) were compared. Additionally, patients were further dichotomized according to predefined SUV
thresholds different from those used in TheraP to analyze their potential impact on outcome as well.
In total, 107 mCRPC patients were included in this analysis (TheraP cePSMA PET-positive,
= 77; TheraP cePSMA PET-negative,
= 30). PSA response rates were higher in TheraP cePSMA PET-positive patients than in TheraP cePSMA PET-negative patients (54.5% vs. 20%, respectively;
= 0.0012). The median PSA progression-free survival (
= 0.007) and OS (
= 0.0007) of patients were significantly longer in the TheraP cePSMA PET-positive group than in the TheraP cePSMA PET-negative group. Moreover, being in the TheraP cePSMA PET-positive group was identified as a significant prognosticator of longer OS (
= 0.003). The application of different SUV
thresholds for a single hottest lesion demonstrated no influence on outcome in patients eligible for PSMA RLT.
Patient selection for PSMA RLT according to the inclusion criteria of TheraP led to a better treatment response and outcome in our preselected patient cohort. However, a relevant number of patients not fulfilling these criteria also showed substantial rates of response.
L-methyl-(11)Cmethionine (MET)-positron emission tomography (PET) has a high sensitivity and specificity for imaging of gliomas and metastatic brain tumors. The short half-life of (11)C (20 minutes) ...limits the use of MET-PET to institutions with onsite cyclotron. O-(2-(18)Ffluoroethyl)-L-tyrosine (FET) is labeled with (18)F (half-life, 120 minutes) and could be used much more broadly. This study compares the uptake of FET and MET in gliomas and metastases, as well as treatment-induced changes. Furthermore, it evaluates the gross tumor volume (GTV) of gliomas defined on PET and magnetic resonance imaging (MRI).
We examined 42 patients with pretreated gliomas (29 patients) or brain metastases (13 patients) prospectively by FET- and MET-PET on the same day. Uptake of FET and MET was quantified by standardized uptake values. Imaging contrast was assessed by calculating lesion-to-gray matter ratios. Tumor extension was quantified by contouring GTV in 17 patients with brain gliomas. Gross tumor volume on PET was compared with GTV on MRI. Sensitivity and specificity of MET- and FET-PET for differentiation of viable tumor from benign changes were evaluated by comparing the PET result with histology or clinical follow-up.
There was a strong linear correlation between standardized uptake values calculated for both tracers in cortex and lesions: r = 0.78 (p = 0.001) and r = 0.84 (p < 0.001), respectively. Image contrast was similar for MET- and FET-PET (lesion-to-gray matter ratios of 2.36 ± 1.01 and 2.33 ± 0.77, respectively). Mean GTV in 17 glioma patients was not significantly different on MET- and FET-PET. Both MET- and FET-PET delineated tumor tissue outside of MRI changes. Both tracers provided differentiated tumor tissue and treatment-related changes with a sensitivity of 91% at a specificity of 100%.
O-(2-(18)Ffluoroethyl)-L-tyrosine-PET and MET-PET provide comparable diagnostic information on gliomas and brain metastases. Like MET-PET, FET-PET can be used for differentiation of residual or recurrent tumor from treatment-related changes/pseudoprogression, as well as for delineation of gliomas.
Preclinical and clinical studies have indicated that somatostatin receptor (sst)-expressing tumors demonstrate higher uptake of radiolabeled sst antagonists than of sst agonists. In 4 consecutive ...patients with advanced neuroendocrine tumors, we evaluated whether treatment with (177)Lu-labeled sst antagonists is feasible.
After injection of approximately 1 GBq of (177)Lu-DOTA-Cpa-c(DCys-Aph(Hor)-DAph(Cbm)-Lys-Thr-Cys)-DTyr-NH2 ((177)Lu-DOTA-JR11) and (177)Lu-DOTATATE, 3-dimensional voxel dosimetry analysis based on SPECT/CT was performed. A higher tumor-to-organ dose ratio for (177)Lu-DOTA-JR11 than for (177)Lu-DOTATATE was the prerequisite for treatment with (177)Lu-DOTA-JR11.
Reversible minor adverse effects of (177)Lu-DOTA-JR11 were observed. (177)Lu-DOTA-JR11 showed a 1.7-10.6 times higher tumor dose than (177)Lu-DOTATATE. At the same time, the tumor-to-kidney and tumor-to-bone marrow dose ratio was 1.1-7.2 times higher. All 4 patients were treated with (177)Lu-DOTA-JR11, resulting in partial remission in 2 patients, stable disease in 1 patient, and mixed response in the other patient.
Treatment of neuroendocrine tumors with radiolabeled sst antagonists is clinically feasible and may have a significant impact on peptide receptor radionuclide therapy.
The role of molecular imaging technologies in detecting, evaluating, and monitoring cardiovascular disease and their treatment is expanding rapidly. Gradually replacing the conventional anatomical or ...physiological approaches, molecular imaging strategies using biologically targeted markers provide unique insight into pathobiological processes at molecular and cellular levels and allow for cardiovascular disease evaluation and individualized therapy. This review paper will discuss currently available and developing molecular-based single-photon emission computed tomography (SPECT) and positron emission tomography (PET) imaging strategies to evaluate post-infarction cardiac remodeling. These approaches include potential targeted methods of evaluating critical biological processes, such as inflammation, angiogenesis, and scar formation.
PET with the glucose analog 18F-FDG is increasingly being used to monitor the effectiveness of therapy in patients with malignant lymphomas and a variety of solid tumors. The use of integrated PET/CT ...instead of stand-alone PET for treatment monitoring poses some methodologic challenges for the quantitative analysis of PET scans but also provides the opportunity to integrate morphologic information and functional information. This integration may allow the definition of new parameters for assessment of the tumor response and will also facilitate the use of PET in research studies as well as in clinical practice. This review addresses how CT-based attenuation correction may affect the quantitative analysis of 18F-FDG PET scans and summarizes the results of recent studies with PET/CT for treatment monitoring for lung cancer and gastrointestinal stromal tumors. The review concludes with an outlook on how PET/CT could make a difference in drug development and clinical management for patients.
Gastrin-releasing peptide (GRP) receptors (GRPr) are frequently overexpressed in human prostate cancer, and radiolabeled GRPr affinity ligands have shown promise for in vivo imaging of prostate ...cancer with PET. The goal of this study was to develop a dual-modality imaging probe that can be used for noninvasive PET imaging and optical imaging of prostate cancer.
We designed and synthesized an IRDye 650 and DOTA-conjugated GRPr antagonist, HZ220 (DOTA-Lys(IRDye 650)-PEG
-D-Phe
, Sta
-BN(6-14)NH
), by reacting DOTA-Lys-PEG
-D-Phe
, Sta
-BN(6-14)NH
(HZ219) with IRDye 650 N-hydroxysuccinimide (NHS) ester. Receptor-specific binding of gallium-labeled HZ220 was characterized in PC-3 prostate cancer cells (PC-3), and tumor uptake in mice was imaged with PET/CT and fluorescence imaging. Receptor binding affinity, in vivo tumor uptake, and biodistribution were compared with the GRPr antagonists HZ219, DOTA-PEG
-D-Phe
, Sta
-BN(6-14)NH
(DOTA-AR), and DOTA-(4-amino-1-carboxymethyl-piperidine)-D-Phe
, Sta
-BN(6-14)NH
(DOTA-RM2).
After hydrophilic-lipophilic balance cartridge purification,
Ga-HZ220 was obtained with a radiochemical yield of 56% ± 8% (non-decay-corrected), and the radiochemical purity was greater than 95%. Ga-HZ220 had a lower affinity for GRPr (inhibitory concentration of 50% IC
, 21.4 ± 7.4 nM) than Ga-DOTA-AR (IC
, 0.48 ± 0.18 nM) or Ga-HZ219 (IC
, 0.69 ± 0.18 nM). Nevertheless,
Ga-HZ220 had an in vivo tumor accumulation similar to
Ga-DOTA-AR (4.63 ± 0.31 vs. 4.07 ± 0.29 percentage injected activity per mL %IA/mL at 1 h after injection) but lower than that of
Ga-DOTA-RM2 (10.4 ± 0.4 %IA/mL). The tumor uptake of
Ga-HZ220 was blocked significantly with an excessive amount of GRP antagonists. IVIS spectrum imaging also visualized PC-3 xenografts in vivo and ex vivo with a high-contrast ratio. Autoradiography and fluorescent-based microscopic imaging with
Ga-HZ220 consistently colocated the expression of GRPr.
Ga-HZ220 displayed a higher kidney uptake than both
Ga-DOTA-AR and
Ga-DOTA-RM2 (16.9 ± 6.5 vs. 4.48 ± 1.63 vs. 5.01 ± 2.29 %IA/mL).
Ga-HZ220 is a promising bimodal ligand for noninvasive PET imaging and intraoperative optical imaging of GRPr-expressing malignancies. Bimodal nuclear/fluorescence imaging may not only improve cancer detection and guide surgical resections, but also improve our understanding of the uptake of GRPr ligands on the cellular level.
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