Objective To estimate the effective dose during 64-slice CT examination on head,chest and abdomen and determine the conversion coefficient of effective dose and dose length product(DLP).Methods The plain CT scan wag performed in 48 cases on head,50 cases on chest and 45 cages on abdomen using GE Lightspeed 64-slice spiral CT.1The Kv,Ma,scan time,CTDIvol,and DLP were recorded in each examination.Effective dose on patients Was estimated using the SR 250 software.Results The effective dose on head,chest and abdomen was(3.1±0.1),(6.9±0.1)and(8.0±0.1)mSv,and the conversion Coeffieient was 0.0025,0.0191 and 0.0166 mSv·mGy-1·cm-1 respectively.Conclusion CTDIvol、DLP and effective dose were recommended for patient dose control during CT examination.The conversion factor of effective dose and DLP were recommended for radiation risk evaluation during different X-ray examinations.

Objective to compare the calculated effective radiation dose variations in cardiac interventional procedures of coronary angiography (CAG) and percutaneous transluminal coronary angioplasty (PCI) by using the different tissue weighting factors recommended by ICRP Publication 60 with that recommended by ICRP Publication 103. Methods Measurements of organ doses were carried out with an anthropomorphic phantom equipped with thermoluminecent dosimetry. The effective radiation doses were separately calculated using the tissue weighting factors provided by ICRP 60 and provided by ICRP 103, and the results obtained from ICRP 60 were compared with that obtained from ICRP 103. Conversion factors of effective, radiation dose to dose area product (DAP) were also calculated according to different publication.Results The variations in the effective dose were 6.88% for CAG and 8.46% for PCI. The effective dose variations in CAG and PCI were. 7.25% and 8.76% for female and were 6.51% and 8.17% for male,respectively. The effective conversion factors of DAP were. 0.10 ～ 0.11 and 0.13 ～ 0.14 for CAG and PCI,respectively, according to ICRP 60 and 103. Conclusion The variation of conversion factors of effective dose indicates that in making estimation of effective radiation dose. by using the widely accepted conversion factors, the adjustment of organ weighting factors recommended by ICRP 103 should be considered.

Objective To assess the dose and image quality using a C-arm CT (DynaCT) system and compare the difference of image quality and radiation dose between DynaCT and Multi slice CT (MSCT). Methods Effective doses were measured from an anthropomorphic phantom with embedded thermoluminescence dosimeters (TLDs).For DynaCT,automatic exposure control (AEC) and high-quality (20 s rotation time) scans were used. For MSCT,scanning protocols for head were examined with conventional exposure conditions. Catphan phantom(Phantom Lab,USA) was used to evaluate the image quality for DynaCT and MSCT. Results For DynaCT,the effective doses from head scanning were 1.10 mSv; for MSCT,the effective doses from head scanning were 2.07 mSv,and there was a significant difference of organ dose between DynaCT and MSCT(P

Objective To investigate the influence of organ dose and effective dose on patients for different Z value during head,chest and abdomen CT scan. Methods With equispaced displacement on axis Z,organ dose and effective dose was estimated by using SR250 software with commonly used CT exposure parameters. Results Effective dose changed gradually for different Z value,some organ dose was sensitive to the Z location. Conclusion It is necessary to avoid X-ray sensitive organ in CT examination to minimize radiation risk.

Objective to compare the calculated effective radiation dose variations in cardiac interventional procedures of coronary angiography(CAG)and percutaneous transluminal coronary angioplasty (PCI)by using the different tissue weighting factors recommended by ICRP Publication 60 with that recommended by ICRP Publication 103.Methods Measurements of organ doses were carried out with an anthropomorphic phantom equipped with thermoluminecent dosimetry.The effective radiation doses were separately calculated using the tissue weighting factors provided by ICRP 60 and provided by ICRP 103,and the results obtained from ICRP 60 were compared with that obtained from ICRP 103.Conversion factors of effective radiation dose to dose area product(DAP)were also calculated according to different publication. Results The variations in the effective dose were 6.88%for CAG and 8.46%for PCI.The effective dose variations in CAG and PCI were 7.25%and 8.76%for female and were 6.51%and 8.17%for male, respectively.The effective conversion factors of DAP were 0.10～0.11 and 0.13～0.14 for CAG and PCI, respectively,according to ICRP 60 and 103.Conclusion The variation of conversion factors of effective dose indicates that in making estimation of effective radiation dose by using the widely accepted conversion factors,the adjustment of organ weighting factors recommended by ICRP 103 should be considered.

Objective: To study the application value of cortical somatosensory evoked potential (CSEP) monitoring in child scoliosis surgery. Methods: In surgeries of fifty-one children with scoliosis, the CSEP changes were continuously recorded by evoked potential instrument. The operations were performed under the guidance of CSEP monitoring. Results: Before propping and reshaping, the latencies and amplitudes in all cases had no change. During propping and reshaping, the latencies of all cases were slowly elongated, but all less than 10 percent. The amplitudes in 15 cases dropped to 55 percent, but returned to 80 percent 3-8 minutes after stopping the operations or partially loosening the propped rods at once. The amplitude in one case suddenly dropped to 37 percent and returned to 54 percent half an hour after loosening the propped rods at once and recovered to the normal range one day after operation. All cases got ideal orthopedic results and no one had neurological complications post operation. Conclusion: CSEP can accurately monitor the spinal injury and has a great value in preventing the spinal injury in child scoliosis surgery.

Adult ; Aged ; Female ; Humans ; Lymphoma ; pathology ; Male ; Middle Aged ; Retrospective Studies ; Splenic Neoplasms ; pathology

Objective To collect information of patient doses of interventional radiology in Beijing Xuanwu Hospital,and investigate correlation between the peak skin dose(PSD) and dose-area product(DAP).Methods Radiation doses from 135 patients have been studied including 84 coronary angiographies(CAG) and 51 percutaneous transluminal coronary angioplasties(PCI).Dose-area product(DAP) values,cumulative dose(CD) at interventional reference points,fluoroscopy times,total number of cine frames were collected for each patient.Skin dose measurements were made with thermoluminescent dosimeters(TLD) placed as a 10 ? 9 arrays of TLDs on the body.The grid of TLDs arrays was 5 ? 4 cm.Results Mean values for dose-area product were 2690.84 ?Gym2 for CAG and 7946.91 ?Gym2 for PCI.Mean values for CD were 431.6 mGy cm2 for CAG and 1395.3 mGy for PCI.Mean fluoroscopy times were 2.9 min for CAG and 10.9 min for PCI and mean number of frames were 544 and 945 for CAG and PCI,respectively.PSD values ranged from 26.18 to 120.37 mGy for CAG and 38.91 to 184.79 mGy for PCI.The relationship between DAP and PSD was r = 0.52 for CAG and r = 0.54 for PCI.The correlation of PSD with CD was r = 0.45 for CAG and r = 0.53 for PCI.Conclusion Comparison shows that patients DAP,CD and fluoroscopy time values were comparable with other publications.Skin dose values of investigated patients are below the threshold dose for radiation skin injury(2 Gy).There is no good relationship between DAP and PSD.So calculation of individual maximum skin dose based on DAP data is not reliable and needs to find a new reference value for skin dose.(J Intervent Radiol,2007,16:222-225)

Objective To evaluate the effect of one-visit endodontic treatment for infected root canals with combination of nickel-titanium instruments and ultrasonic technique and warm vertical technique.Methods According to treatment,90 teeth were randomly divided into experimental and control groups.Two groups were used nickel titarlium root canal preparation.Experimental group:51 teeth for ultrasonic root canal irrigation,and warm vertical technique was employed to fill the root canal.Control group:39 teeth for rinse syringes,and warm vertical technique was employed to fill the root canal.Washing fluid was 2％ sodium hypochlorite.The root canal filling was observed after a week and one year of postoperative pain response.Results A week later,two groups of post-operative pain showed that there was significant difference in responses (x2 =15.525,P ＜ 0.05).One year later,the two groups showed no significant difference in efficacy(x2 =0.085,P ＞ 0.05).Conclusion The combination of nickel-titanium instruments and ultrasonic irrigation technique and warm vertical obturation,for the treatment of infected root canals was a method to complete the root canal filling,could reduce both the number of patients subsquent visits and the postoperative pain response,while it could improve the quality of root canal filling.

Objective To establish an animal model of vulnerable plaque in abdominal aorta by pharmacological triggering of atherosclerosis in rabbits. Methods Thirty New Zealand white rabbits were randomly and equally divided into 3 groups: group A, receiving balloon injury together with high lipid diet; group B, receiving high lipid diet only, and group C, receiving regular diet only. After feeding for 12 weeks, all the rabbits in three groups underwent pharmacological triggering with Chinese Russell's viper venom (CRVV) and histamine to induce the rupture of the plaque and the formation of thrombosis. Results In 8 survival rabbits of group A, ten lesions with the stenotic degree over 50% were found, which had large lipid core with the thickness of fibrous cap being thinner than 65μm, by which these ten lesions were judged as vulnerable plaques. In 9 rabbits of group B, only 3 vulnerable plaques could be determined, while no single vulnerable plaque could be identified in the rabbits of group C. Conclusion For establishing an animal model of vulnerable plaque in abdominal aorta in rabbits, balloon injury combined with high lipid diet is a feasible and reliable method.