GPU-accelerated three-dimensional reconstruction method of the Compton camera and its application in radionuclide imaging

A novel and fast three-dimensional reconstruction method for a Compton camera and its performance in radionuclide imaging is proposed and analyzed in this study. The conical surface sampling back-projection method with scattering angle correction(CSS-BP-SC) can quickly perform the back-projection process of the Compton cone and can be used to precompute the list-mode maximum likelihood expectation maximization(LM-MLEM). A dedicated parallel architecture was designed for the graphics processing unit acceleration of the back-projection and iteration stage of the CSS-BP-SC-based LM-MLEM. The imaging results of the two-point source Monte Carlo(MC) simulation demonstrate that by analyzing the full width at half maximum along the three coordinate axes, the CSS-BP-SC-based LM-MLEM can obtain imaging results comparable to those of the traditional reconstruction algorithm, that is, the simple back-projection-based LM-MLEM. The imaging results of the mouse phantom MC simulation and experiment demonstrate that the reconstruction results obtained by the proposed method sufficiently coincide with the set radioactivity distribution, and the speed increased by more than 664 times compared to the traditional reconstruction algorithm in the mouse phantom experiment. The proposed method will further advance the imaging applications of Compton cameras.

A novel approach for feature extraction from a gamma‑ray energy spectrum based on image descriptor transferring for radionuclide identification

This study proposes a novel feature extraction approach for radionuclide identification to increase the precision of identification of the gamma-ray energy spectrum set.For easier utilization of the information contained in the spectra,the vectors of the gamma-ray energy spectra from Euclidean space,which are fingerprints of the different types of radionuclides,were mapped to matrices in the Banach space.Subsequently,to make the spectra in matrix form easier to apply to image-based deep learning frameworks,the matrices of the gamma-ray energy spectra were mapped to images in the RGB color space.A deep convolutional neural network(DCNN)model was constructed and trained on the ImageNet dataset.The mapped gamma-ray energy spectrum images were applied as inputs to the DCNN model,and the corresponding outputs of the convolution layers and fully connected layers were transferred as descriptors of the images to construct a new classification model for radionuclide identification.The transferred image descriptors consist of global and local features,where the activation vectors of fully connected layers are global features,and activations from convolution layers are local features.A series of comparative experiments between the transferred image descriptors,peak information,features extracted by the histogram of the oriented gradients(HOG),and scale-invariant feature transform(SIFT)using both synthetic and measured data were applied to 11 classical classifiers.The results demonstrate that although the gamma-ray energy spectrum images are completely unfamiliar to the DCNN model and have not been used in the pre-training process,the transferred image descriptors achieved good classification results.The global features have strong semantic information,which achieves an average accuracy of 92.76%and 94.86%on the synthetic dataset and measured dataset,respectively.The results of the statistical comparison of features demonstrate that the proposed approach outperforms the peak-searching-based method,HOG,and SIFT on the synthetic and measured datasets.

EVALUATION OF RADIONUCLIDE BONE IMAGING FOR SKELETAL DISEASE

Whole body bone scan imaging of 99mTc-MDP was performed in 80 casesfrom Sept 1991 to Feb 1992. Among them 20 patients showed negtive bone imaging and56 patients showed positive bone imaging. There were false-positive bone imaging in 4 pa-tients. Bone scan imaging has been regarded as a useful method in the early diagnosis ofshelatal disease, especially in old patients with bone metastasis. But the final confirmationof malignancy should be still cautious.

Role of radionuclide imaging for diagnosis of device and prosthetic valve infections

Cardiovascular implantable electronic device(CIED) infection and prosthetic valve endocarditis(PVE) remain a diagnostic challenge.Cardiac imaging plays an important role in the diagnosis and management of patients with CIED infection or PVE.Over the past few years,cardiac radionuclide imaging has gained a key role in the diagnosis of these patients,and in assessing the need for surgery,mainly in the most difficult cases.Both ^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography(^(18)F-FDG PET/CT) and radiolabelled white blood cell single-photon emission computed tomography/computed tomography(WBC SPECT/CT) have been studied in these situations.In their 2015 guidelines for the management of infective endocarditis,the European Society of Cardiology incorporated cardiac nuclear imaging as part of their diagnostic algorithm for PVE,but not CIED infection since the data were judged insufficient at the moment.This article reviews the actual knowledge and recent studies on the use of ^(18)F-FDG PET/CT and WBC SPECT/CT in the context of CIED infection and PVE,and describes the technical aspects of cardiac radionuclide imaging.It also discusses their accepted and potential indications for the diagnosis and management of CIED infection and PVE,the limitations of these tests,and potential areas of future research.

Imaging assessment of photosensitizer emission induced by radionuclide-derived Cherenkov radiation using charge-coupled device optical imaging and long-pass filters

BACKGROUND Radionuclides produce Cherenkov radiation(CR),which can potentially activate photosensitizers(PSs)in phototherapy.Several groups have studied Cherenkov energy transfer to PSs using optical imaging;however,cost-effectively identifying whether PSs are excited by radionuclide-derived CR and detecting fluorescence emission from excited PSs remain a challenge.Many laboratories face the need for expensive dedicated equipment.AIM To cost-effectively confirm whether PSs are excited by radionuclide-derived CR and distinguish fluorescence emission from excited PSs.METHODS The absorbance and fluorescence spectra of PSs were measured using a microplate reader and fluorescence spectrometer to examine the photo-physical properties of PSs.To mitigate the need for expensive dedicated equipment and achieve the aim of the study,we developed a method that utilizes a chargecoupled device optical imaging system and appropriate long-pass filters of different wavelengths(manual sequential application of long-pass filters of 515,580,645,700,750,and 800 nm).Tetrakis(4-carboxyphenyl)porphyrin(TCPP)was utilized as a model PS.Different doses of copper-64(^(64)CuCl_(2))(4,2,and 1 mCi)were used as CR-producing radionuclides.Imaging and data acquisition were performed 0.5 h after sample preparation.Differential image analysis was conducted by using ImageJ software(National Institutes of Health)to visually evaluate TCPP fluorescence.RESULTS The maximum absorbance of TCPP was at 390-430 nm,and the emission peak was at 670 nm.The CR and CRinduced TCPP emissions were observed using the optical imaging system and the high-transmittance long-pass filters described above.The emission spectra of TCPP with a peak in the 645-700 nm window were obtained by calculation and subtraction based on the serial signal intensity(total flux)difference between^(64)CuCl_(2)+TCPP and^(64)CuCl_(2).Moreover,the differential fluorescence images of TCPP were obtained by subtracting the^(64)CuCl_(2)image from the^(64)CuCl_(2)+TCPP image.The experimental results considering different^(64)CuCl_(2)doses showed a dosedependent trend.These results demonstrate that a bioluminescence imaging device coupled with different longpass filters and subtraction image processing can confirm the emission spectra and differential fluorescence images of CR-induced TCPP.CONCLUSION This simple method identifies the PS fluorescence emission generated by radionuclide-derived CR and can contribute to accelerating the development of Cherenkov energy transfer imaging and the discovery of new PSs.

RADIONUCLIDE WHOLE BODY BONE IMAGING IN THE DIAGNOSIS OF SKELETAL METASTASES

Of 628 patients with extra-osseous malignancies diagnosed by surgery and/or pathology, 207 (33.0%) were identified as having skeletal metastasis by bone imaging. There was statistical significant difference in the incidence of metastasis in different malignancies (P<0.02). The metastatic rates of nasopharyn-geal, lung, prostate and breast cancers were higher than gastrointestinal, kidney, and other malignancies. There was significant differences in the different sites of skeletal metastasis (P<0.01). They were thorax, spine, pelvis, limbs and skull in order of incidence. Solitary metastatic rate was 15.9%. Biopsy is advised for patients suspected to have metastatic disease but with only one single 'hot spot' in skeletal imaging, particularly in the rib.

Neoadjuvant peptide receptor radionuclide therapy for an inoperable neuroendocrine pancreatic tumor

Pancreatic endocrine tumors are rare but are among the most common neuroendocrine neoplasms of the abdomen.At diagnosis many of them are already advanced and diff icult to treat.We report on an initially inoperable malignant pancreatic endocrine tumor in a 33-year-old woman,who received neoadjuvant peptide receptor radionuclide therapy(PRRT)as firstline treatment.This resulted in a signif icant downstaging of the tumor and allowed its subsequent complete surgical removal.Follow-up for eighteen months revealed a complete remission.This is the first report on neoadjuvant PRRT in a neuroendocrine neoplasm with subsequent successful complete resection.

Current update on imaging for pancreatic neuroendocrine neoplasms

Pancreatic neuroendocrine neoplasms(panNEN)are a heterogeneous group of tumors with differing pathological,genetic,and clinical features.Based on clinical findings,they may be categorized into functioning and nonfunctioning tumors.Adoption of the 2017 World Health Organization classification system,particularly its differentiation between grade 3,well-differentiated pancreatic neuroendocrine tumors(panNET)and grade 3,poorly-differentiated pancreatic neuroendocrine carcinomas(panNEC)has emphasized the role imaging plays in characterizing these lesions.Endoscopic ultrasound can help obtain biopsy specimen and assess tumor margins and local spread.Enhancement patterns on computed tomography(CT)and magnetic resonance imaging(MRI)may be used to classify panNEN.Contrast enhanced MRI and diffusion-weighted imaging have been reported to be useful for characterization of panNEN and quantifying metastatic burden.Current and emerging radiotracers have broadened the utility of functional imaging in evaluating panNEN.Fluorine-18 fluorodeoxyglucose positron emission tomography(PET)/CT and somatostatin receptor imaging such as Gallium-681,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid–octreotate PET/CT may be useful for improved identification of panNEN in comparison to anatomic modalities.These new techniques can also play a direct role in optimizing the selection of treatment for individuals and predicting tumor response based on somatostatin receptor expression.In addition,emerging methods of radiomics such as texture analysis may be a potential tool for staging and outcome prediction in panNEN,however further investigation is required before clinical implementation.

Comparative Study of _(99m)TcN(NOEt)_2 and ^(99m)Tc-MIBI Imaging in Mice Bearing Ehrlich Ascites Tumor

Objective To evaluate and compare the ability to detect tumor by bis (N-ethoxy-N-ethyl dithiocarbamato) nitrido99mTc(V) [99mTcN(NOEt)2] and99mTc hexakis-2- methoxyisobutyl isonitrile [99mTc-MIBI]. Methods 99mTcN(NOEt)2 was prepared and quality control was performed using ascending thin-layer chromatography. Four mice bearing Ehrich ascites tumor cells underwent whole body planar imaging at 30 min, 2 h and 4 h after injection of99mTc-MIBI or99mTcN(NOEt)2. ROIs were drawn around the tumor, head, chest, and contralateral limbs in whole body planar images, and ratios of radioactivity in tumor in head (T/H), chest (T/C), and contralateral limbs (T/L) were calculated. The mice of99mTcN (NOEt)2 group were killed, then blood was collected, and the tumor and organs were excised, weighed and the radioactivity was measured. Results 99mTcN(NOEt)2 was stable after 4h at the room temperature.99mTcN(NOEt)2 was delivered to the tumor selectively and efficiently.99mTcN(NOEt)2 was found to provide excellent tumor-to-nontumor contrast for all the tissue except the abdomen. The T/L ratios increased to their maximums (4.87) at 2 h after injection. There was significant difference between the99mTcN(NOEt)2 imaging group and99mTc-MIBI imaging group. In vitro the radioactivity ratios per unit weight of tumor to blood, muscle, skeleton, lung, heart, and spleen were much higher than those of tumor to liver, instestine. Conclusion In mice bearing Ehrich ascites tumor,99mTcN(NOEt)2 exhibits a set of features essential for a good tracer for tumor imaging, including a rapid washout from blood, high uptake rate in tumor tissue, prolonged retention and high tumor-to-nontumor uptake ratio. The imaging quality of99mTcN(NOEt)2 was superior to that of99mTc-MIBI. These features indicate that99mTcN(NOEt)2 may be a better tracer to detect tumor than99mTc-MIBI. Key words tumor - radionuclide imaging - NOEt - MIBI

Imaging of bone metastasis: An update

Early detection of skeletal metastasis is critical for accurate staging and optimal treatment. This paper briefly reviews our current understanding of the biological mechanisms through which tumours metastasise to bone and describes the available imaging methods to diagnose bone metastasis and monitor response to treatment. Among the various imaging modalities currently available for imaging skeletal metastasis, hybrid techniques whichfuse morphological and functional data are the most sensitive and specific, and positron emission tomography(PET)/computed tomography and PET/magnetic resonance imaging will almost certainly continue to evolve and become increasingly important in this regard.

Evaluation of ^(99m)Tc Labeled Diadenosine Tetraphosphate as an Atherosclerotic Plaque Imaging Agent in Experimental Models

The potential of ^99mTc labeled P^1, P^4-di （adenosine-5 ＇ ）-tetraphosphate （Ap4A） for imaging experimental atherosclerotic plaques was evaluated in New Zealand white （NZW） rabbits. To label the ^99mTc to Ap4A, stannous tartrate solution was used. ^99mTc-Ap4A was purified on a Sephadex G-25 column. The radiochemistry purities of ^99mTc-Ap4A were 85% to 91%. Biodistribution study revealed ^99mTc-Ap4A cleared from blood rapidly. Thirty min after ^99mTc-Ap4A administrated on NZW atherosclerotic rabbits, lesion to blood （target/blood, T/B） ratio was 3. 17 ±1.27, and lesions to normal （target/non-target, T/NT） ratio was 5.23 ±1.87. Shadows of atherosclerotic plaques were clearly visible on radioautographic film. Aortas with atherosclerotic plaques also could be seen on ex vivo gamma camera images. Atherosclerotic abdominal aortas were clearly visible on in vivo images 15 min to 3 h after ^99mTc-Ap4A administration. ^99mTc-labeled Ap4A can be used for rapid noninvasive detection of experimental atherosclerotic plaque.

A novel denoising framework for cerenkov luminescence imaging based on spatial information improved clustering and curvature-driven diffusion

With widely availed clinically used radionuclides,Cer enkov luminescence imaging(CLI)has become a potential tool in the field of optical molecular imaging.However,the impulse noises introduced by high-energy gamma rays that are generated during the decay of radionuclide reduce the image quality significantly,which affects the acauracy of quantitative analysis,as well as the three dimensional reconstruction.In this work,a novel denoising framework based on fuzzy dlustering and curvat ure driven difusion(CDD)is proposed to remove this kind of impulse noises.To improve the accuracy,the F u1zzy Local Information C-Means algorithm,where spatial information is evolved,is used.We evaluate the per formance of the proposed framework sys-tematically with a series of experiments,and the corresponding results demonstrate a better denoising effect than those from the commonly used median filter method.We hope this work may provide a useful data pre processing tool for CLI and its following studies.

THE VALUE OF^(99m) Tc-MIBI MYOCARDIAL PERFUSION SPECT IMAGING IN DETECTING CORONARY ARTERY DISEASE IN PATIENTS WITH VALVULAR DISEASE BEFORE OPERATION

The aim of this study was to detect coronary artery disease using 99m Tc MIBI myocardial perfusion imaging in patients with valvular disease. [WT5”BX]Methods.[WT5”BZ] Thirty patients with valvular disease confirmed by echocardiography underwent 99m Tc MIBI myocardial perfusion imaging using multiSPECT 1h after stress test (exercise, dipyridamole or dobutamine test) and were performed coronary angiography within 1 month before valvular operation. [WT5”BX]Results.[WT5”BZ]For 29 out of the 30 patients, the results of 99m Tc MIBI myocardial perfusion imaging were similar with those of coronary angiography, the concordance rate was 96 7% and the negative predictability was 100%. [WT5”BX]Conclusion.[WT5”BZ] 99m Tc MIBI myocardial perfusion imaging is a reliable non invasive method for detecting coronary artery disease in patients with valvular disease and so as to draw up suitable operation programs for them.

Studies on the Distribution and Radioimmunoimaging of ^(99m)Tc-Labeled 5-Fluorouracil Loaded Immunological Nanoparticles in Tissues and Human Gastric Carcinoma Xenografts

OBJECTIVE To explore the method of preparation of 99m↑Tc labeled AntiVEGF McAb 5-FU loaded polylactic acid nanoparticles （99m↑TC-5-FU-Ab-NPs）, and investigate the biological distribution of the nanoparticles in human gastric carcinoma xenografts. METHODS Anti-VEGF monoclonal antibodyes （MCAB）in 5-FU-Ab-NPs were labeled with 99m↑Tc using a modified Schwarz method. After isolation of the 99m↑TC-5-FU-Ab-NPs using a Sephadex G-250 column, the labeling percentage and radiochemical purity were determined using paper chromatography. The immunocempetence of the 99m↑TC-5-FU-Ab-NPs as tumor markers was determined using ELISA and immunohistochemistry. 99m↑TC-5-FU-Ab-NPs （experimental group）, 99m↑Tc-labelled murine multiclonal IgG loaded polylactic acid and nanoparticles （control group） were injected via the tail vein into SCID mice bearing human gastric carcinoma. A radio-immunity ECT image was developed at 2 and 6 h after the injection. Following the ECT imaging, the mice were sacrificed, their tissue and tumor radioactivity distribution determined, and percentage of the injected-dose per gram （%ID/g） and tumor/ nontumor （T/NT） ratio calculated. High performance liquid chromatography （HPLC） was used to determine the 5-FU concentration in the tumor tissue and blood in the mice of both groups. RESULTS The percentage of 99m↑TC-5-FU-Ab-NPs labeling was 90%-95%. There was no obvious decrease in the antibody activity before and after labeling. The radio-immuno-imaging （RII） showed that the tumor image had developed 2 h after injection of the 99m↑TC-5-FU-Ab-NPs, and with time it was clearer at the 6th hour following the injection. The %lD/g of the tumor tissue at both 2 h and 6 h after the injection was significantly higher compared to the control group. The tumor %lD/g and the tumor to blood activity ratio （TB） of the experimental group at 6 h following the injection increased compared to that at 2 h, and at the same time, 5-FU concentration in the tumor of the experimental group continuously increased over time, and showed a significant difference compared to the 5-FU concentration in the tumor of the control group. CONCLUSION The 99m↑TC-5-FU-Ab-NPs prepared in this study are adequate to meet the demands of the RII, and the immune targeting ability of the anti-VEGF MCAB is reliable. Six hours after injection, the 99m↑TC-5-FU-Ab-NPs showed a relatively high specific concentration shadow in the human gastric carcinoma xenografts.

Joint imaging of ^(99m)TcO_4^- and ^(99m)Tc-MIBI for thyroid carcinoma recurrence and cervical metastases

In this paper, the joint imaging of 99mTcO4- and 99mTc-methoxy isobutyl isonitrile was compared with neck Color Doppler Ultrasonography (CDU) to identify its value in thyroid carcinoma, postoperative recurrence or cervical metastases. Thyroid carcinoma patients (150 operated and 21 re-operated with suspected postoperative recurrence or cervical metastases) were retrospectively analyzed. Taking the pathological result as the gold standard, the thyroid foci (437 cases), the thyroid foci of ≥1-cm diameter (215 cases) and the suspected postoperative recurrence or cervical metastases (87 cases) were compared by diagnostic results of the joint imaging and the neck CDU. The sensitivity, specificity and accuracy of the joint imaging were 64.18%, 80.00% and 67.82%, and 44.78%, 40.00% and 43.68%, respectively, for the cases with suspected postoperative recurrence or cervical metastases. For thyroid carcinoma of ≥1-cm diameter, the sensitivity of the joint imaging was 97.75%, and the neck CDU was 89.89%, but both specificity and accuracy was similar for thyroid carcinoma independence on their diameter. For thyroid carcinoma, the sensitivity of the joint imaging was 81.99%, and the neck CDU was 89.10%. The results show that the joint imaging is sensitive for large diameter thyroid carcinoma.

Preclinical pharmacology study of neutral myocardial imaging agent ^(99m)TcN(NOEt)_2

To explore the biological properties of a new neutral myocardial imaging agent 99mTcN（NOEt）2,preparation and characterization of 99mTeN（NOEt）2, kinetics of blood-drug clearance in rabbits, biodistribution in rats, test of undue toxicity in mice and myocardial imaging in dogs were performed and volunteer imaging. Radiochemical purity of 99mTeN（NOEt）2 was over than 90% and stable for 6 hours at room temperature. Blood disappearance was analyzed with biexponential model, T1/2（α）=2.53 min, T1/2 （β）=330 min and Cl=378 mL/h were obtained. Biodistribution studies demonstrated that 99mTcN（NOEt）2 localized selectively in myocardium of rats. Cardiac uptake were 2.79, 2.25, 2.00 and 1.88%ID/organ at 5, 30, 60 and 90min of postinjection, respectively. The heart-to-lung activity ratio was 1.16 at 60 min. Images showed that pulmonary uptake decreased faster than cardiac uptake in a dog. The mean heart-to-lung activity ratios in a dog were 1.69, 2.40 and 2.55 at 10, 30 and 60min of postinjection, respectively. The heart was distinguishable on scans at 30min. Whole body imaging showed that cardiac uptake was 2.82%ID at 90min, but hepatic uptake was 30%ID and remained constant. The test of undue toxicity showed that the dose received by mice was 614 times as by human. Volunteer imaging suggests 99mTcN（NOEt）2 redistribution with time. 99mTcN（NOEt）2 exhibited favorable stabilities, biological properties and safety. It is worth for further studying in human.

The preclinical pharmacological study of dopamine transporter imaging agent ^(18)F-FP-β-CIT

The paper is to study pharmacologic characteristics of 18F-FP-β-CIT (18F-N-(3-fluoropropyl)-2β-carbomethoxy-3β- (4-iodophenyl)nortropane) as an imaging agent for dopamine transporter. The radiochemical purity of 18F-FP-β-CIT in aqueous solution was over 95% after standing at room temperature for 4h. Biodistribution displayed rapid uptake in rat brain (1.375 %ID/organ at 5min and 0.100 %ID/organ at 180 min) and the striatal uptake was 1.444, 0.731, 0.397, 0.230 and 0.146 %ID/g at 5, 30, 60, 120 and 180 min, respectively. The values of striatum/cerebellum, striatum /frontal cortex and striatum / hippocampus in rat's brain at 30 min were 3.38, 2.17 and 2.40 respectively. The uptake in striatum can be blocked by β-CFT, suggesting that 18F-FP-β-CIT binds to DAT peculiarly. The compound was rapidly cleared from monkey's blood. The striatal uptake was bilaterally decreased in the left-sided lesioned PD rats, compared with normal control. Brain PET imaging studies in normal monkey showed that 18F-FP-β-CIT was concentrated in striatum. The test of undue toxicity showed that the dose received by mice was 1250 times as by human, which indicates that 18F-FP-β-CIT is very safe. So 18F-FP-β-CIT is a promising PET imaging agent for DAT with safety and validity.

Research on the interaction mechanism between quantum dots and radionuclides for the improvement of Cerenkov luminescence imaging

Cerenkov luminescence imaging(CLI) is a relatively new optical molecular imaging technique. The nature of Stokes shift in quantum dots(QD) can be used to improve the quality of CLI. However, the interaction mechanism of QD with Cerenkov light remains unclear. In this work, the interaction mechanism between QD and radionuclides emitting β rays, γ rays, and Cerenkov light was investigated. The 96-well plates were used to test the different levels of radioactivity of radionuclides with different QD concentrations. Transparent vials were used to determine the relationship between QD fluorescence intensity and the distance from QD to the radionuclide. In addition, black paper was used to block the transmission of Cerenkov light through the QD vials. A linear relationship was found between the number of photons and the radioactivity of radionuclides when the QD concentration was kept constant. Similarly, the number of photons was linearly related to the QD concentration when the radioactivity of radionuclides was kept constant. Furthermore, with the increases in the distance between radionuclides and quantum dots, the number of photons was exponentially decreased. Meanwhile, the number of photons emitted from QD excited by Cerenkov light accounted for 20% the total number of photons excited by 131 I radionuclide. The result proved that QD was not only excited by Cerenkov light but also by other rays.

Recent advances in diagnosis and treatment of gastroenteropancreatic neuroendocrine neoplasms

Gastroenteropancreatic neuroendocrine neoplasms(GEP-NENs)are a rare group of tumors originating from neuroendocrine cells of the digestive system.Their incidence has increased over the last decades.The specific pathogenetic mechanisms underlying GEP-NEN development have not been completely revealed.Unfunctional GEP-NENs are usually asymptomatic;some grow slowly and thus impede early diagnosis,which ultimately results in a high rate of misdiagnosis.Therefore,many GEP-NEN patients present with later staged tumors.Motivated hereby,research attention for diagnosis and treatment for GEP-NENs increased in recent years.The result of which is great progress in clinical diagnosis and treatment.According to the most recent clinical guidelines,improved grading standards can accurately define poorly differentiated grade 3 neuroendocrine tumors and neuroendocrine carcinomas(NECs),which are subclassified into large and small cell NECs.Combining different functional imaging methods facilitates precise diagnosis.The expression of somatostatin receptors helps to predict prognosis.Genetic analyses of mutations affecting death domain associated protein(DAXX),multiple endocrine neoplasia type 1(MEN 1),alpha thalassemia/intellectual disability syndrome X-linked(ATRX),retinoblastoma transcriptional corepressor 1(RB 1),and mothers against decapentaplegic homolog 4(SMAD 4)help distinguishing grade 3 NENs from poorly differentiated NECs.The aim of this review is to summarize the latest research progress on diagnosis and treatment of GEP-NENs.

Image fusion using MIM software via picture archiving and communication system

The preliminary studies of the multimodality image registration and fusion were performed using an image fusion software and a picture archiving and communication system (PACS) to explore the methodology. Original image voluminal data were acquired with a CT scanner, MR and dual-head coincidence SPECT, respectively. The data sets from all imaging devices were queried, retrieved, transferred and accessed via DICOM PACS. The image fusion was performed at the SPECT ICON work-station, where the MIM (Medical Image Merge) fusion software was installed. The images were created by reslicing original volume on the fly. The image volumes were aligned by translation and rotation of these view ports with respect to the original volume orientation. The transparency factor and contrast were adjusted in order that both volumes can be visualized in the merged images. The image volume data of CT, MR and nuclear medicine were transferred, accessed and loaded via PACS successfully. The perfect fused images of chest CT/18F-FDG and brain MR/SPECT were obtained. These results showed that image fusion technique using PACS was feasible and practical. Further experimentation and larger validation studies were needed to explore the full potential of the clinical use.