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PS02.062: CONFOCAL LASER ENDOMICROSCOPY IN THE ASSESSMENT OF PERSISTENT/RECURRENT INTESTINAL METAPLASIA/NEOPLASIA AFTER ENDOSCOPIC TREATMENT OF BORN
摘要： Recent studies revealed that membrane proteins, such as ion transporters, are specifically activated in cancer stem cells (CSCs). Therefore, these molecules are receiving a great attention as new chemotherapeutic targets of malignant tumor. This study aimed to investigate the expression and activity of ion transport-related molecules in CSCs of esophageal squamous cell carcinoma (ESCC).
关键词： Esophageal squamous cell carcinoma,FDG-PET/CT,esophageal cancer,Esophageal cancer,stem cell,TRPV2,Tranilast,False positive,LncRNA
更新于2025-09-11 14:15:04
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Repeatability of <sup>18</sup> F-FDG PET Radiomic Features: a Phantom Study to Explore Sensitivity to Image Reconstruction Settings, Noise, and Delineation Method
摘要： Background: 18F-fluoro-2-deoxy-D-Glucose positron emission tomography (18F-FDG PET) radiomics has the potential to guide the clinical decision making in cancer patients, but validation is required before radiomics can be implemented in the clinical setting. The aim of this study was to explore how feature space reduction and repeatability of 18F-FDG PET radiomic features are affected by various sources of variation such as underlying data (e.g. object size and uptake), image reconstruction methods and settings, noise, discretization method, and delineation method.
关键词： 18F-FDG PET/CT radiomic features,delineation,image reconstruction settings
更新于2025-09-10 09:29:36
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The feasibility of dedicated breast PET for the assessment of residual tumor after neoadjuvant chemotherapy
摘要： Purpose To evaluate the utility of ring-type dedicated breast positron emission tomography (dbPET) for the detection of the residual tumor after neoadjuvant chemotherapy (NAC). Materials and methods This prospective study included 27 women with histologically proven breast cancer over a 37-month period. All patients underwent ring-type dbPET followed by whole-body PET-CT (WBPET) for preoperative tumor evaluation and re-staging after NAC. The maximum standardized uptake value (SUVmax) of the tumor lesion and the degree of confidence for the presence of the residual tumor were compared between pathological complete response (pCR) and non-pCR tumors. The sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) for the detection of a non-pCR tumor were compared between dbPET and WBPET. Results On dbPET, SUVmax was significantly higher in non-pCR than in pCR tumors (P = 0.030). The sensitivity for the detection of a non-pCR tumor was significantly higher with dbPET than with WBPET (84.2% vs 26.3%, P = 0.001). In the qualitative analysis, the sensitivity for the detection of a non-pCR tumor was also significantly higher with dbPET than with WBPET (57.9% vs 21.1%, P = 0.016). Conclusion The dbPET can provide more sensitive detection of residual tumor after NAC than can WBPET.
关键词： Breast cancer,Dedicated breast positron emission tomography,Neoadjuvant chemotherapy,Whole-body PET-CT,Residual tumor
更新于2025-09-10 09:29:36
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Cancer Theranostics || Multimodality Image-Guided Treatment
摘要： Recent advances in molecular biology and imaging technology with precision engineering have allowed in vivo imaging of anatomic structures at submillimeter ranges and pathologic processes at subnanomolar concentrations. Multimodality imaging is exemplified by the current practice of single photon emission computed tomography (SPECT-CT) and positron emission tomography computed tomography (PET-CT) [1]. Subcentimeter lesions on computed tomotraphy (CT) can be characterized by functional abnormalities identified on SPECT to enhance sensitivity of detecting radio-isotopes or PET, which routinely assess lesion glucose metabolism using F-18 FDG (fluorine-18 fluoro-2-fluorodeoxyglucose). Conversely, subcentimeter hypermetabolic lesions on SPECT or PET can be identified on CT to allow exact localization to guide various types of therapy including surgery, radiotherapy, and experimental therapies. Guided therapies target abnormal tissues, which often refer to, but are not limited to, neoplasms. For instance, drainage of an abdominal bacterial abcess may require scintigraphic confirmation of infection to determine the need of intervention and anatomic guidance from CT or magnetic resonance imaging (MRI) to access the lesion.
关键词： Cancer treatment,Radiotherapy,Multimodality imaging,PET-CT,SPECT-CT,Surgery,Image-guided therapy,Molecular imaging
更新于2025-09-10 09:29:36
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Compton camera based on Timepix3 technology
摘要： The Compton camera concept is based on the reconstruction of recorded Compton scattering events of incoming gamma rays. The scattering of primary gamma ray occurs in the first detector (called scattering detector — usually thin) recording the position and energy of the recoiled electron. The scattered gamma quantum continues towards the second detector (called absorption detector - usually thick) where it is absorbed. The second detector records the energy and the position of this scattered gamma. Using the Compton scattering equation it is possible to determine the scattering angle, and estimate possible directions of the original gamma ray as a surface of a cone. When the Compton camera records the number of such events, the location and the shape of the gamma source can be reconstructed. Timepix3, a hybrid single photon counting imaging pixel detector, is a perfect device for creation of a compact Compton camera. Timepix3 is an event based readout chip (every hit pixel is immediately sent to a readout) and can record the time-of-arrival (ToA) and energy of an incident gamma simultaneously in each pixel. The chip offers high energy resolution (1 keV at 60 keV, 7 keV at 356 keV), as well as time resolution (1.6 ns). The Timepix3 readout chip can be combined with different sensor materials (Si, CdTe, CZT). In this contribution, we present a very compact detector system for imaging with gamma-rays using the Compton camera principle. The system consists of at least two layers of hybrid pixel detectors Timepix3 with the sensors being optimized for gamma-ray tracking. The front detector layer (scattering) is made of silicon of 1 mm thickness, while the last layer (absorbing) is equipped with thick CdTe or CZT sensors up to 2 mm in thickness. The total absorption of the whole detector can be very high if several CdTe or CZT layers are used. The maximal number of layers is not limited, but the practical evaluation was performed with 2 layers. Thanks to Timepix3 simultaneous measurement of ToA and energy, it is possible to precisely detect coincidence events in the detector layers. Based on the energy and position of these events, it is possible to estimate the possible direction of the original gamma. The angular resolution of the presented Compton camera depends on the detected energy, and it is in the order of 1 degree.
关键词： PET PET/CT,coronary CT angiography (CTA),Gamma camera,Particle tracking detectors,Compton imaging,SPECT
更新于2025-09-09 09:28:46
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Simulation and evaluation of high-performance cost-effective positron emission mammography scanner
摘要： Breast cancer is the main cause of tumor deaths in women, thus several imaging modalities have been introduced recently to better diagnose the disease. New breast cancer cases were estimated to reach up to 246,660 in 2017, and the mortality rate was above 40,000. Early diagnosis is widely approved as being essential for an e?ective treatment and it also helps to reduce the incidences and mortality rates. Positron Emission Mammography (PEM) is a breast-dedicated imaging device which uses a pair of annihilation gamma photons to detect abnormalities in the breast tissue. PEM device is compact in nature with a reduced ?eld of view to cover the entire breast region, and it employs few detector modules which makes it cost-e?cient. To e?ectively diagnose breast cancer at a very early stage, a device with high spatial resolution and high sensitivity is required. PEM detectors based on semiconductor materials are characterized by an excellent intrinsic spatial resolution but are not cost-e?ective, whereas detectors based on scintillator crystals are cost-e?ective but have limited intrinsic resolution to detect small breast lesions. This study focuses on improving the resolution of scintillator detectors by simulating a PEM scanner employing 1 × 1 × 10 mm3 laser processed scintillator crystal. The simulation was done with a GEANT4 application for emission tomography (GATE) software, and performance evaluation tests were carried out according to the National Electrical Manufacturers Association (NEMA) standards. The scanner geometry has 90 mm transaxial ?eld of view (FOV) and 105 mm axial FOV. Evaluation results showed that the scanner has 10.6% system sensitivity, 1.0 mm spatial resolution at the center of the FOV (CFOV) and at 2.5 cm transaxial direction. The resolution at the axial 2.5 cm position is 2.1 mm. NEMA image quality test and Derenzo phantom study showed that the scanner can easily resolve 1 mm in diameter hot rods.
关键词： PET PET/CT,X-ray mammography and scinto- and MRI-mammography,coronary CT angiography (CTA),Gamma camera,SPECT
更新于2025-09-09 09:28:46
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PET-Computed Tomography and PET-MR Imaging and Their?Applications in the Twenty-First Century
摘要： Since the discovery of x-ray by Roentgen in 1895, planar radiography has remained a major imaging technique in assessing skeletal abnormalities with reasonable success. However, poor contrast between diseased sites and the background results in low sensitivity of this modality in detecting early disease and monitoring its course over time. The introduction of computed tomography (CT) in 1971 by Hounsfield further enhanced the role of x-ray-based disease assessment, and as such, XCT has played an important role in the day-to-day management of musculoskeletal (MSK) disorders. Since the early 1980s, when the first MR imaging instruments were introduced for human studies, the impact of imaging for examining soft tissue abnormalities in MSK disorders has been substantially enhanced. Currently, XCT and MR imaging are the main imaging modalities available in this domain but suffer from many deficiencies that need to be addressed by employing more advanced approaches. Since the early 1970s, 99m-Technitium (Tc)-labeled phosphates have been extensively used to detect benign and malignant disorders of the skeletal system. These radiotracers allow planar and tomographic imaging (SPECT [single-photon emission computed tomography]), but the quality of images generated is somewhat suboptimal for detection of the affected sites and quantification of the disease activity.
关键词： PET-CT-MRI,musculoskeletal disorders,radiotracers,FDG-PET,imaging,18F-NaF
更新于2025-09-09 09:28:46
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How to harmonize SUVs obtained by hybrid PET/CT scanners with and without point spread function correction
摘要： State of the art point-spread function (PSF) corrections implemented in positron emission tomography/computed tomography (PET/CT) reconstruction improved image quality and diagnostic performance but caused an increase in the standardized uptake value (SUV) compared to a conventional OSEM reconstruction system. The EANM suggested one produce two reconstructions, one optimised for maximum lesion detection and one for semi-quantitative analysis. In this work we investigated an alternative methodology, using a single reconstruction data set together with a post-reconstruction algorithm for SUV harmonization. Data acquisition was performed on a Siemens Biograph mCT system equipped with lutetium oxyorthosilicat crystals, PSF and time-of-flight algorithms and on a General Electric Discovery STE system equipped with BGO crystals. Both a EANM double reconstruction method and a dedicated post-reconstruction algorithm (marketed as EQ-filter) were tested to harmonize the quantitative values of the two PET/CT scanners. For phantom measurements we used a NEMA IQ phantom and a Jaszczak cylindrical phantom equipped with small spheres (lesion to background ratios of 8:1 and 4:1). Several different reconstruction settings were tested in order to provide a general methodology. Data obtained by phantom measurements were validated on seven oncologic patients who performed a one-bed extra acquisition on a different scanner. The evaluation regarded 39 small lesions (diameters: 0.3–2.6 cm) and was performed by two experienced nuclear medicine physicians. The SUV recoveries measured with the PSF reconstruction exceeded those obtained by the OSEM reconstruction with deviations ranging from 16% to 150%. These discrepancies resulted below 7% applying the optimized value of the EQ.filter or the double-reconstruction methods. For each reconstruction setting the optimal value of the EQ.filter was identified in order to minimize these discrepancies. Patient data, analyzed by Wilcoxon statistical test, confirmed and validated phantom measurements. EQ.filter can harmonize SUV values between different PET/CT scanners using a single reconstruction optimized to maximum lesion detectability. In this way, the second reconstruction proposed by EANM/EARL is avoided.
关键词： EQ.filter,PSF,EARL accreditation program,PET/CT scanners,SUV harmonization
更新于2025-09-09 09:28:46
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Radiobiological Modeling Based on 18F-Fluorodeoxyglucose Positron Emission Tomography Data for Esophageal Cancer
摘要： Background: We investigated the relationship of standardized uptake values (SUVs) to radiobiological parameters, such a 25 s tumor control probability (TCP), to allow for quantitative prediction of tumor response based on SUVs from 18F fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) before and after treatment for esophageal cancer. Methods: We analyzed data from 20 esophageal cancer patients treated with chemoradiotherapy (CRT) followed by surgery. Tumor pathologic response to CRT was assessed in surgical specimens. Patients underwent 18F-FDG PET imaging before and after CRT. Rigid image registration was performed between both images. Because TCP in a heterogeneous tumor is a function of average cell survival, we modeled TCP as a function of <SUVR>, a possible surrogate for average cell survival (<SUVR>=<SUVafter/SUVbefore>). TCP was represented by a sigmoid function with two parameters: SUVR50, the <SUVR> at which TCP=0.5, and γ50, the slope of the curve at SUVR50. The two parameters and their confidence intervals (CIs) were estimated using the maximum-likelihood method. The correlation between SUV before CRT and SUV change <SUVbefore – SUVafter> was also studied. Results: A TCP model as a function of SUV before and after treatment was developed for esophageal cancer patients. The maximum-likelihood estimate of SUVR50 was 0.47 (90% CI, 0.30-0.61) and for γ50was 1.62 (90% CI, 0-4.2). High initial SUV and larger metabolic response (larger <SUVbefore –SUVafter>) were correlated, and this correlation was stronger among responders. Conclusions: Our TCP model indicates that <SUVafter/SUVbefore> is a possible surrogate for cell survival in esophageal cancer patients. Although CIs are large as a result of the small patient sample, parameters for a TCP curve can be derived and an individualized TCP can be calculated for future patients. Initial SUV does not predict response, whereas a correlation is found between surrogates for initial tumor burden and cell kill during therapy.
关键词： Quantitative imaging,Esophageal cancer,18F-FDG PET/CT,Tumor response,Radiation therapy
更新于2025-09-09 09:28:46
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Utility of first positron emission tomography-computed tomography scan as a prognostic tool following treatment of sinonasal and skull base malignancies
摘要： Background: The prognostic value of the first posttreatment whole body integrated positron emission tomography-computed tomography (PET/CT) scanning in patients with sinonasal/skull base malignancies is undetermined. Methods: We retrospectively reviewed the data of all patients that underwent surgery for sinonasal/skull base malignancies in 2000-2015. The results of the pretreatment and posttreatment PET/CT findings and the clinical course were retrieved. Results: Thirty-eight patients (average age 60.6 years, 20 males) were included. Sensitivity and specificity, positive predictive value, and negative predictive value of the first PET/CT scan for predicting persistent/recurrent disease were 85.7%, 87.5%, 80%, and 91.3%, respectively. Overall 5-year survival was significantly lower in the first posttreatment PET/CT-positive group (35%) compared to the PET/CT-negative group (93%) (P = .0008). Conclusion: Posttreatment PET/CT findings are highly prognostic in patients with sinonasal/skull base malignancies. Negative findings on the first posttreatment PET/CT scan predict a significantly better overall survival.
关键词： sinonasal malignancy,skull base,prognosis,PET/CT,survival
更新于2025-09-09 09:28:46