Image quality in positron emission tomography(PET)is affected by random and scattered coincidences and reconstruction protocols.In this study,we investigated the effects of scattered and random coincidences from outsi...Image quality in positron emission tomography(PET)is affected by random and scattered coincidences and reconstruction protocols.In this study,we investigated the effects of scattered and random coincidences from outside the field of view(FOV)on PET image quality for different reconstruction protocols.Imaging was performed on the Discovery 690 PET/CT scanner,using experimental configurations including the NEMA phantom(a body phantom,with six spheres of different sizes)with a signal background ratio of 4:1.The NEMA phantom(phantom I)was scanned separately in a one-bed position.To simulate the effect of random and scatter coincidences from outside the FOV,six cylindrical phantoms with various diameters were added to the NEMA phantom(phantom II).The 18 emission datasets with mean intervals of 15 min were acquired(3 min/scan).The emission data were reconstructed using different techniques.The image quality parameters were evaluated by both phantoms.Variations in the signal-to-noise ratio(SNR)in a 28-mm(10-mm)sphere of phantom II were 37.9%(86.5%)for ordered-subset expectation maximization(OSEM-only),36.8%(81.5%)for point spread function(PSF),32.7%(80.7%)for time of flight(TOF),and 31.5%(77.8%)for OSEM+PSF+TOF,respectively,indicating that OSEM+PSF+TOF reconstruction had the lowest noise levels and lowest coefficient of variation(COV)values.Random and scatter coincidences from outside the FOV induced lower SNR,lower contrast,and higher COV values,indicating image deterioration and significantly impacting smaller sphere sizes.Amongst reconstruction protocols,OSEM+PSF+TOF and OSEM+PSF showed higher contrast values for sphere sizes of 22,28,and 37 mm and higher contrast recovery coefficient values for smaller sphere sizes of 10 and 13 mm.展开更多
Background:Intrahepatic cholangiocarcinoma(ICC)is a highly metastatic cancer.^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography(^(18)F-FDG PET/CT)enables sensitive tumor and metastasis detectio...Background:Intrahepatic cholangiocarcinoma(ICC)is a highly metastatic cancer.^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography(^(18)F-FDG PET/CT)enables sensitive tumor and metastasis detection.Our aim is to evaluate the influence of pre-treatment PET/CT on the N-and M-staging and subsequent clinical management in ICC patients.Methods:Between August 2010 and August 2018,660 consecutive ICC patients,without prior anti-tumor treatments nor other malignancies,were enrolled.The diagnostic performance of PET/CT on the N-and M-staging was compared with conventional imaging,and the preoperative staging accuracy and treatment re-allocation by PET/CT were retrospectively calculated.Survival difference was compared between patients receiving PET/CT or not after propensity score matching.Results:Patients were divided into group A(n=291)and group B(n=369)according to whether PET/CT was performed.Among 291 patients with both PET/CT and conventional imaging for staging in group A,PET/CT showed significantly higher sensitivity(83.0%vs.70.5%,P=0.001),specificity(88.3%vs.74.9%,P<0.001)and accuracy(86.3%vs.73.2%,P<0.001)than conventional imaging in diagnosing regional lymph node metastasis,as well as higher sensitivity(87.8%vs.67.6%,P<0.001)and accuracy(93.5%vs.89.3%,P=0.023)in diagnosing distant metastasis.Overall,PET/CT improved the accuracy of preoperative staging from 60.1%to 71.8%(P<0.001),and modified clinical treatment strategy in 5.8%(17/291)of ICC patients,with unique roles in different tumor-node-metastasis(TNM)stages.High tumor-to-non-tumor ratio(TNR)predicted poor overall survival[hazard ratio(HR)=2.17;95%confidence interval(CI):1.49-3.15;P<0.001].Furthermore,patients performing PET/CT had longer overall survival compared with those without PET/CT(HR=0.74;95%CI:0.58-0.93;P=0.011)after propensity score matching.Conclusions:PET/CT was valuable for diagnosing regional lymph node metastasis and distant metastasis in ICC patients,and facilitated accurate tumor staging and optimal treatment allocation.展开更多
Ewing sarcoma/primary neuroectodermal tumors are rare,invasive,and small round blue cell tumors.There are few reports of its occurrence in the urinary system.Here,we present the first middle-aged female patient whose ...Ewing sarcoma/primary neuroectodermal tumors are rare,invasive,and small round blue cell tumors.There are few reports of its occurrence in the urinary system.Here,we present the first middle-aged female patient whose Ewing sarcoma primary site was in the ureter.The main clinical manifestation was intermittent hematuria.She was in good health after complete surgical resection and adjuvant radiotherapy.To date,there has been no recurrence or metastasis.Accurate early diagnosis and appropriate treatment can help prolong survival.18F-fluorodeoxyglucose positron emission tomography/computed tomography is expected to be an effective means of evaluating treatment effects and detecting metastasis and recurrence.In this article,besides introducing a case of Ewing sarcoma/primitive neuroectodermal tumor of the ureter,we review the literature to discuss the current status of diagnosis and treatment.展开更多
基金supported by the Tehran University of Medical Sciences under Grant No.36291PET/CT and Cyclotron Center of Masih Daneshvari Hospital at Shahid Beheshti University of Medical Sciences。
文摘Image quality in positron emission tomography(PET)is affected by random and scattered coincidences and reconstruction protocols.In this study,we investigated the effects of scattered and random coincidences from outside the field of view(FOV)on PET image quality for different reconstruction protocols.Imaging was performed on the Discovery 690 PET/CT scanner,using experimental configurations including the NEMA phantom(a body phantom,with six spheres of different sizes)with a signal background ratio of 4:1.The NEMA phantom(phantom I)was scanned separately in a one-bed position.To simulate the effect of random and scatter coincidences from outside the FOV,six cylindrical phantoms with various diameters were added to the NEMA phantom(phantom II).The 18 emission datasets with mean intervals of 15 min were acquired(3 min/scan).The emission data were reconstructed using different techniques.The image quality parameters were evaluated by both phantoms.Variations in the signal-to-noise ratio(SNR)in a 28-mm(10-mm)sphere of phantom II were 37.9%(86.5%)for ordered-subset expectation maximization(OSEM-only),36.8%(81.5%)for point spread function(PSF),32.7%(80.7%)for time of flight(TOF),and 31.5%(77.8%)for OSEM+PSF+TOF,respectively,indicating that OSEM+PSF+TOF reconstruction had the lowest noise levels and lowest coefficient of variation(COV)values.Random and scatter coincidences from outside the FOV induced lower SNR,lower contrast,and higher COV values,indicating image deterioration and significantly impacting smaller sphere sizes.Amongst reconstruction protocols,OSEM+PSF+TOF and OSEM+PSF showed higher contrast values for sphere sizes of 22,28,and 37 mm and higher contrast recovery coefficient values for smaller sphere sizes of 10 and 13 mm.
基金supported by project grants from the National Natural Science Foundation of China(Nos.91859105,and 81961128025)the Program of Shanghai Academic Research Leader(No.19XD1420700)+1 种基金the Science and Technology Commission of Shanghai Municipality(No.20JC1418900)the Shanghai Municipal Key Clinical Specialty.
文摘Background:Intrahepatic cholangiocarcinoma(ICC)is a highly metastatic cancer.^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography(^(18)F-FDG PET/CT)enables sensitive tumor and metastasis detection.Our aim is to evaluate the influence of pre-treatment PET/CT on the N-and M-staging and subsequent clinical management in ICC patients.Methods:Between August 2010 and August 2018,660 consecutive ICC patients,without prior anti-tumor treatments nor other malignancies,were enrolled.The diagnostic performance of PET/CT on the N-and M-staging was compared with conventional imaging,and the preoperative staging accuracy and treatment re-allocation by PET/CT were retrospectively calculated.Survival difference was compared between patients receiving PET/CT or not after propensity score matching.Results:Patients were divided into group A(n=291)and group B(n=369)according to whether PET/CT was performed.Among 291 patients with both PET/CT and conventional imaging for staging in group A,PET/CT showed significantly higher sensitivity(83.0%vs.70.5%,P=0.001),specificity(88.3%vs.74.9%,P<0.001)and accuracy(86.3%vs.73.2%,P<0.001)than conventional imaging in diagnosing regional lymph node metastasis,as well as higher sensitivity(87.8%vs.67.6%,P<0.001)and accuracy(93.5%vs.89.3%,P=0.023)in diagnosing distant metastasis.Overall,PET/CT improved the accuracy of preoperative staging from 60.1%to 71.8%(P<0.001),and modified clinical treatment strategy in 5.8%(17/291)of ICC patients,with unique roles in different tumor-node-metastasis(TNM)stages.High tumor-to-non-tumor ratio(TNR)predicted poor overall survival[hazard ratio(HR)=2.17;95%confidence interval(CI):1.49-3.15;P<0.001].Furthermore,patients performing PET/CT had longer overall survival compared with those without PET/CT(HR=0.74;95%CI:0.58-0.93;P=0.011)after propensity score matching.Conclusions:PET/CT was valuable for diagnosing regional lymph node metastasis and distant metastasis in ICC patients,and facilitated accurate tumor staging and optimal treatment allocation.
文摘Ewing sarcoma/primary neuroectodermal tumors are rare,invasive,and small round blue cell tumors.There are few reports of its occurrence in the urinary system.Here,we present the first middle-aged female patient whose Ewing sarcoma primary site was in the ureter.The main clinical manifestation was intermittent hematuria.She was in good health after complete surgical resection and adjuvant radiotherapy.To date,there has been no recurrence or metastasis.Accurate early diagnosis and appropriate treatment can help prolong survival.18F-fluorodeoxyglucose positron emission tomography/computed tomography is expected to be an effective means of evaluating treatment effects and detecting metastasis and recurrence.In this article,besides introducing a case of Ewing sarcoma/primitive neuroectodermal tumor of the ureter,we review the literature to discuss the current status of diagnosis and treatment.
