AIM To clarify the association of malignancy with mesenteric panniculitis-like changes on computed tomography(CT).METHODS All abdominal CT scans performed at North Shore University HealthS ystem showing mesenteric pan...AIM To clarify the association of malignancy with mesenteric panniculitis-like changes on computed tomography(CT).METHODS All abdominal CT scans performed at North Shore University HealthS ystem showing mesenteric panniculitis from January 2005 to August 2010 were identified in the Radnet(Rad Net Corporation, Los Angeles, CA) database. Patients with a new or known diagnosis of a malignancy were included for this analysis. Longitudinal clinical histories were obtained from electronic medical records.RESULTS In total, 147794 abdominal CT scans were performed during the study period. Three hundred and fiftynine patients had mesenteric panniculitis(MP)-like abnormalities on their abdominal CT. Of these patients, 81 patients(22.6%) had a known history of cancer at the time of their CT scan. Nineteen(5.3%) had a new diagnosis of cancer in concurrence with their CT, but the majority of these(14/19, 74%) were undergoing CT as part of a malignancy evaluation. Lymphomas were the most common cancers associated with MPlike findings on CT(36 cases, 36%), with follicular lymphoma being the most frequent subtype(17/36). A variety of solid tumors, most commonly prostate(7) and renal cell cancers(6) also were seen. CT follow up was obtained in 56 patients. Findings in the mesentery were unchanged in 45(80%), worsened in 6(11%), and improved in 5 patients(9%). Positron emission tomography(PET) scans performed in 44 patients only showed a positive uptake in the mesenteric mass in 2 patients(5%). CONCLUSION A new diagnosis of cancer is uncommon in patients with CT findings suggestive of MP. MP-like mesenteric abnormalities on CT generally remain stable in patients with associated malignancies. PET scanning is not recommended in the evaluation of patients with mesenteric panniculitis-like findings on CT.展开更多
The pore structure images of ore particles located at different heights of leaching column were scanned with X-ray computerized tomography (CT) scanner, the porosity and pore size distribution were calculated and the ...The pore structure images of ore particles located at different heights of leaching column were scanned with X-ray computerized tomography (CT) scanner, the porosity and pore size distribution were calculated and the geometrical shape and connectivity of pores were analyzed based on image process method, and the three dimensional reconstruction of pore structure images was realized. The results show that the porosity of ore particles bed in leaching column is 42.92%, 41.72%, 39.34% at top, middle and bottom zone, respectively. Obviously it has spatial variability and decreases appreciably along the height of the column. The overall average porosity obtained by image processing is 41.33% while the porosity gotten from general measurement method in laboratory is 42.77% showing the results of both methods are consistent well. The pore structure of ore granular media is characterized as a dynamical space network composed of interconnected pore bodies and pore throats. The ratio of throats with equivalent diameter less than 1.91 mm to the total pores is 29.31%, and that of the large pores with equivalent diameter more than 5.73 mm is 2.90%.展开更多
Background: In 2010, the International Atomic Energy Agency launched the “3A’s campaign” as an effective tool for primary cancer prevention. In 2011, the American Association of Physicists in Medicine recommended t...Background: In 2010, the International Atomic Energy Agency launched the “3A’s campaign” as an effective tool for primary cancer prevention. In 2011, the American Association of Physicists in Medicine recommended the size specific dose estimate (SSDE). Objectives: To audit doses of Coronary CT Angiography (Coronary CTA) in tertiary care referral center. Methods: We reviewed 998 consecutive Coronary CTA (from 2007 to 2012). Doses (CTDIvol mGy), DLP (mGy*cm), effective dose (DLP*0.014, mSv) were on-line archived. SSDE was estimated retrospectively. Appropriateness score was evaluated for exams performed from the 2010. Results: Overall median dose per Coronary CTA was 49.7 mGy for CTDIvol, 55.5 mGy for SSDE, 994.96 mGy*cm for DLP, 13.9 mSv for effective dose. Median DLP decreased over time (1452.94 in 2007, 1605.56 in 2008, 1113.49 in 2009, 759.99 in 2010, 448.61 in 2011 and 497.88 mGy*cm in 2012, p < 0.0001). SSDE was proportional to the size dependent factor (SDF);in patients with SDF > 1 (88%) CTDIvol underestimated SSDE (48.49 vs 57.19 mGy), whilst in patients with SDF < 1 (12%) CTDIvol overestimated SSDE (56.46 vs 50.3 mGy). Scans were appropriate in 58%, uncertain in 24%, and inappropriate in 18% of cases. Doses were similar in appropriate, uncertain or inappropriate examinations and in excellent-to-good (81%) vs. sufficient-to-poor (19%) image quality exams. Conclusions: Coronary CTA reference doses can be very misleading. SSDE can allow individual technique optimization. The dose is similar in appropriate and inappropriate examinations, and unrelated to image quality. The rate of inappropriate examinations is still too high even after dissemination of guidelines.展开更多
Objectives To compare the different patterns of coronary artery calcification (CAC) in acute and chronic coronary syndromes utilizing electron beam computed tomography. Background Pathologic, angiographic, and intraco...Objectives To compare the different patterns of coronary artery calcification (CAC) in acute and chronic coronary syndromes utilizing electron beam computed tomography. Background Pathologic, angiographic, and intracoronary ultrasound studies revealed sharp differences in the plaque morphology between patients with acute versus chronic coronary syndromes. Whether there are different patterns of coronary artery calcification in patients with stable angina pectoris (SAP) and in those with unstable angina pectoris (UAP) or acute myocardial infarction (AMI), however, remains unclear. Methods Two hundred and sixty - four patients, including 67 with SAP, 94 with UAP and 103 with AMI were studied with electron beam computed tomography for analysis of coronary artery calcification and with selective coronary angiography for determination of atherosclerotic lesions. CAC prevalence and calcium score were compared among three groups, and relation of CAC to the severity of atherosclerotic disease in the SAP and UAP patients was separately analyzed. Results Prevalence of CAC was 100 % in the SAP patients, significantly higher than the 87. 23 % in UAP patients and 86. 41 % among the patients with AMI ( P < 0. 05) . More patients and arteries in the SAP group had severe forms of calcium than those in the UAP and AMI group ( P < 0. 01), and the mean LN [CS + 1] (natural logarithm transformation of calcium score) of the SAP patients was much greater than that of the UAP and AMI patients (P < 0.001). The distribution of vessels with various CAC by luminal stenosis was different between SAP and UAP patients. The average CAC extent of the infarct - related arteries was less severe than that of the noninfarct - related arteries. Conclusions U-tilizing electron beam computed tomography, we demonstrated that there exist different patterns of coronary artery calcification in patients with acute versus chronic coronary syndromes, which may provide insight into the differences observed in the clinical and pathologic development between these two types of coronary artery disease.展开更多
A tomography device based on a conventional laboratory x ray source, polycapillary parallel x ray lens （PPXRL）, and polycapillary collimating x ray lens （PCXRL） is designed. The PPXRL can collect the divergent x r...A tomography device based on a conventional laboratory x ray source, polycapillary parallel x ray lens （PPXRL）, and polycapillary collimating x ray lens （PCXRL） is designed. The PPXRL can collect the divergent x ray beam from the source and focus it into a quasi-parallel x ray beam with a divergence of 4.7 rarad. In the center of quasi-parallel x ray beam, there is a plateau region with an average gain in power density of 13.8 and a diameter of 630μm. The contrast of the image can be improved from 28.9% to 56.0% after adding the PCXRL between the sample and the detector.展开更多
A new type of solid-conversion gas detector is investigated for high energy X-ray industrial computed tomography (HECT). The conversion efficiency is calculated by using the EGSnrc Monte Carlo code on the Linux platfo...A new type of solid-conversion gas detector is investigated for high energy X-ray industrial computed tomography (HECT). The conversion efficiency is calculated by using the EGSnrc Monte Carlo code on the Linux platform to simulate the transport process of photons and electrons in the detector. The simulation results show that the conversion efficiency could be more than 65%, if the X-ray beam width is less than about 0.2 mm, and a tungsten slab with 0.2 mm thickness and 30 mm length is employed as a radiation conversion medium. Meanwhile the results indicate that this new detector has higher conversion efficiency as well as less volume. Theoretically this new kind of detector could take place of the traditional scintillation detector for HECT.展开更多
基金Supported by An unrestricted grant from the Keyser Family Fund(partly)
文摘AIM To clarify the association of malignancy with mesenteric panniculitis-like changes on computed tomography(CT).METHODS All abdominal CT scans performed at North Shore University HealthS ystem showing mesenteric panniculitis from January 2005 to August 2010 were identified in the Radnet(Rad Net Corporation, Los Angeles, CA) database. Patients with a new or known diagnosis of a malignancy were included for this analysis. Longitudinal clinical histories were obtained from electronic medical records.RESULTS In total, 147794 abdominal CT scans were performed during the study period. Three hundred and fiftynine patients had mesenteric panniculitis(MP)-like abnormalities on their abdominal CT. Of these patients, 81 patients(22.6%) had a known history of cancer at the time of their CT scan. Nineteen(5.3%) had a new diagnosis of cancer in concurrence with their CT, but the majority of these(14/19, 74%) were undergoing CT as part of a malignancy evaluation. Lymphomas were the most common cancers associated with MPlike findings on CT(36 cases, 36%), with follicular lymphoma being the most frequent subtype(17/36). A variety of solid tumors, most commonly prostate(7) and renal cell cancers(6) also were seen. CT follow up was obtained in 56 patients. Findings in the mesentery were unchanged in 45(80%), worsened in 6(11%), and improved in 5 patients(9%). Positron emission tomography(PET) scans performed in 44 patients only showed a positive uptake in the mesenteric mass in 2 patients(5%). CONCLUSION A new diagnosis of cancer is uncommon in patients with CT findings suggestive of MP. MP-like mesenteric abnormalities on CT generally remain stable in patients with associated malignancies. PET scanning is not recommended in the evaluation of patients with mesenteric panniculitis-like findings on CT.
基金Project(2004CB619205) supported by the National Key Fundamental Research and Development Program of ChinaProject(50325415) supported by the National Science Fund for Distinguished Young ScholarsProject(50574099) supported by the National Natural Science Foundation of China
文摘The pore structure images of ore particles located at different heights of leaching column were scanned with X-ray computerized tomography (CT) scanner, the porosity and pore size distribution were calculated and the geometrical shape and connectivity of pores were analyzed based on image process method, and the three dimensional reconstruction of pore structure images was realized. The results show that the porosity of ore particles bed in leaching column is 42.92%, 41.72%, 39.34% at top, middle and bottom zone, respectively. Obviously it has spatial variability and decreases appreciably along the height of the column. The overall average porosity obtained by image processing is 41.33% while the porosity gotten from general measurement method in laboratory is 42.77% showing the results of both methods are consistent well. The pore structure of ore granular media is characterized as a dynamical space network composed of interconnected pore bodies and pore throats. The ratio of throats with equivalent diameter less than 1.91 mm to the total pores is 29.31%, and that of the large pores with equivalent diameter more than 5.73 mm is 2.90%.
文摘Background: In 2010, the International Atomic Energy Agency launched the “3A’s campaign” as an effective tool for primary cancer prevention. In 2011, the American Association of Physicists in Medicine recommended the size specific dose estimate (SSDE). Objectives: To audit doses of Coronary CT Angiography (Coronary CTA) in tertiary care referral center. Methods: We reviewed 998 consecutive Coronary CTA (from 2007 to 2012). Doses (CTDIvol mGy), DLP (mGy*cm), effective dose (DLP*0.014, mSv) were on-line archived. SSDE was estimated retrospectively. Appropriateness score was evaluated for exams performed from the 2010. Results: Overall median dose per Coronary CTA was 49.7 mGy for CTDIvol, 55.5 mGy for SSDE, 994.96 mGy*cm for DLP, 13.9 mSv for effective dose. Median DLP decreased over time (1452.94 in 2007, 1605.56 in 2008, 1113.49 in 2009, 759.99 in 2010, 448.61 in 2011 and 497.88 mGy*cm in 2012, p < 0.0001). SSDE was proportional to the size dependent factor (SDF);in patients with SDF > 1 (88%) CTDIvol underestimated SSDE (48.49 vs 57.19 mGy), whilst in patients with SDF < 1 (12%) CTDIvol overestimated SSDE (56.46 vs 50.3 mGy). Scans were appropriate in 58%, uncertain in 24%, and inappropriate in 18% of cases. Doses were similar in appropriate, uncertain or inappropriate examinations and in excellent-to-good (81%) vs. sufficient-to-poor (19%) image quality exams. Conclusions: Coronary CTA reference doses can be very misleading. SSDE can allow individual technique optimization. The dose is similar in appropriate and inappropriate examinations, and unrelated to image quality. The rate of inappropriate examinations is still too high even after dissemination of guidelines.
文摘Objectives To compare the different patterns of coronary artery calcification (CAC) in acute and chronic coronary syndromes utilizing electron beam computed tomography. Background Pathologic, angiographic, and intracoronary ultrasound studies revealed sharp differences in the plaque morphology between patients with acute versus chronic coronary syndromes. Whether there are different patterns of coronary artery calcification in patients with stable angina pectoris (SAP) and in those with unstable angina pectoris (UAP) or acute myocardial infarction (AMI), however, remains unclear. Methods Two hundred and sixty - four patients, including 67 with SAP, 94 with UAP and 103 with AMI were studied with electron beam computed tomography for analysis of coronary artery calcification and with selective coronary angiography for determination of atherosclerotic lesions. CAC prevalence and calcium score were compared among three groups, and relation of CAC to the severity of atherosclerotic disease in the SAP and UAP patients was separately analyzed. Results Prevalence of CAC was 100 % in the SAP patients, significantly higher than the 87. 23 % in UAP patients and 86. 41 % among the patients with AMI ( P < 0. 05) . More patients and arteries in the SAP group had severe forms of calcium than those in the UAP and AMI group ( P < 0. 01), and the mean LN [CS + 1] (natural logarithm transformation of calcium score) of the SAP patients was much greater than that of the UAP and AMI patients (P < 0.001). The distribution of vessels with various CAC by luminal stenosis was different between SAP and UAP patients. The average CAC extent of the infarct - related arteries was less severe than that of the noninfarct - related arteries. Conclusions U-tilizing electron beam computed tomography, we demonstrated that there exist different patterns of coronary artery calcification in patients with acute versus chronic coronary syndromes, which may provide insight into the differences observed in the clinical and pathologic development between these two types of coronary artery disease.
基金supported by the National Natural Science Foundation of China(No.11375027)the Fundamental Research Funds for the Central Universities(No.2014k JJCA03)
文摘A tomography device based on a conventional laboratory x ray source, polycapillary parallel x ray lens （PPXRL）, and polycapillary collimating x ray lens （PCXRL） is designed. The PPXRL can collect the divergent x ray beam from the source and focus it into a quasi-parallel x ray beam with a divergence of 4.7 rarad. In the center of quasi-parallel x ray beam, there is a plateau region with an average gain in power density of 13.8 and a diameter of 630μm. The contrast of the image can be improved from 28.9% to 56.0% after adding the PCXRL between the sample and the detector.
基金supported by the National Natural Science Foundation of China (No.60672098)the Tackling Key Problems of Science and Technology of ChongQing (No.CSTC2009AC3047)
文摘A new type of solid-conversion gas detector is investigated for high energy X-ray industrial computed tomography (HECT). The conversion efficiency is calculated by using the EGSnrc Monte Carlo code on the Linux platform to simulate the transport process of photons and electrons in the detector. The simulation results show that the conversion efficiency could be more than 65%, if the X-ray beam width is less than about 0.2 mm, and a tungsten slab with 0.2 mm thickness and 30 mm length is employed as a radiation conversion medium. Meanwhile the results indicate that this new detector has higher conversion efficiency as well as less volume. Theoretically this new kind of detector could take place of the traditional scintillation detector for HECT.
