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Objective:To investigate the effect of the combination of Auto-prescription and ODM full on image quality and radiation dose of chest enhanced CT inorder to explore the feasibility of individualized low radiation dose chest enhanced CT. Methods:The phantoms PH-75 in two sizes were scanned with four scanning modes: group A, 120 kVp + Smart-mA; group B, 120 kVp + Smart-mA+ ODM full; group C, Auto-prescription + Smart-mA; group D, Auto-prescription + Smart-mA+ ODM full. The images of each group were reconstructed with 40%-80% ASIR-V (interval 20%), recorded as A 1-3-D 1-3. Image quality and radiation dose were evaluated in order to obtain optimal scanning modes. Totally 35 cases(from the First Hospital of Dalian Medical University during November 2021 to July 2022) of chest enhancement CT were collected prospectively in the clinical study using the parameters of D 2 group recorded as D patients. Patients in this group received chest enhancement CT scanning for the second time within three months. The CT parameters in first enhanced scanning recorded as A patient were as same as those in group A 1, and the parameters in second scanning recorded as D patient were as same as those in group D 2. The SNRs, CNRs, subjective grading and imaging findings of the lesion in two groups were compared. Results:In phantom study, the radiation dose of each group was statistically significant, and that in D group was the lowest. For two sizes of phantoms, A 1 was uesd as the control group in pairwise comparison. The SDs of B 1, C 1, and D 2 images had no statistical difference with that of A 1 ( P > 0.05), and SD of D 1was higher than that of A 1, and SDs of other groups were lower than that of A 1( F=10.77, 122.50, P<0.05). CNR of B 1 had no statistical difference with that of A 1, and the CNRs of other groups were higher( F=136.20, 30.21, P<0.05). Subjective scores of A 2, C 2, D 2 had no statistical difference with that of A 1 and those of other groups were lower than that of A 1( H=52.89, 43.95, P<0.05). In clinical study, 80 kVp was uesd for 22 cases and 100 kVp was used for 13 cases in D patients group. SNRs and CNRs in the D patients group were all higher than those in the A patients group ( P > 0.05). The consistency of image quality scores for two observers was good ( kappa = 0.754, P < 0.05). The median scores of the two groups were (4, 4). Conclusion:Auto-prescription combined with ODM full in chest enhanced CT imaging can achieve individualized low radiation dose with meeting the requirements of image quality and clinical diagnosis.
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Objective To investgate the application value of low-dose CT scanning in right adrenal vein imaging.Methods A total of 124 patients were enrolled in the study who were suspected as primary aldosteronism and requiring a contrast enhanced CT examination on adrenal glands.Four patients were excluded according to the exclusion criteria,so that the rest 120 patients were divided equally into three groups.Group A was a control group with conventional radiation dose using tube voltage of 120 kV and automatic mA.It was divided into A1,A2 and A3 groups according to arterial phase,portal venous phase and parenchymal phase.Group B was a experimental group with conventional tube voltage of 120 kV and automatic mA,which was divided into B1,B2 and n3 groups according to arterial phase,late arterial phase and portal venous phase.Group C was a low-dose experimental group with a tube voltage of 100 kV and a tube current of 150 mA only in the second phase,the remaining scanning parameters and method were the same as that of group B.The subjective scores of the images of groups A,B and C were statistically analyzed,and the CT values of the right adrenal vein(RAV),the right adrenal gland(RAG),and the fat of anterior abdominal wall at different scan phases were measured.The dose length products (DLP) were recorded and the signal-to-noise ratios (SNR),contrast-to-noise ratios (CNR),effective doses (E) of the three groups were calculated and compared.Results The subjective scores of the two observers were consistent (Kappa value =0.63);the subjective scores of the B2 images were statistically significant (H =7.18,P＜0.05).Difference of subjective scores between B2 and A2was statistically significant (t=-18.03,P＜0.05).The CT values of RAV,SNR,and CNR of the B2 group were higher than those of the A2 group (t=36.99,6.92,9.02,P＜0.05).The radiation dose comparison showed that the effective dose (E) was 45.52％ lower in the low-dose group than the conventional dose group with the statistically significant difference(t =12.19,P＜0.05).Conclusions Using MDCT scanning technique with lower tube voltage and lower tube current of 100 kV-150 mA,the detection rate of right adrenal vein can reach 95％ in the late arterial phase,and the effective dose can be reduced about 45.52％ on the basis of ensuring image quality.
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Objective To assess the image quality (IQ) of an iterative reconstruction (IR) technique(sinogram affirmed iterative reconstruction,SAFIRE) for upper limb intravascular fistula CT angiography on a second generation dual-source CT scanner and determine the optimal dose level using IR with IQ comparable to filtered back projection(FBP).Methods The experiment was a prospective study.A total of 150 patients were averagely divided into 5 groups to perform upper limb intravascular fistula CT angiography.The control group was scanned with conventional tube output (120 kV,110 mAs) and images were reconstructed with FBP.The tube current of the other 4 groups (reconstructed with SAFIRE) was successively reduced to 70％,60％,50％ and 40％ of that of control group.Quantitative measurements of signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were obtained in two regions of interest (ROI) in each group.The ROIs were placed at the subclavian artery near shoulder joint,and the stoma of radial artery and cephalic vein.Analysis of variance (ANOVA) was used for comparisons of objective evaluation parameters (SNR,CNR) and radiation dose (CTDIvol,DLP,E) among 5 groups.Two radiologists graded IQ in a blinded fashion on a 4-point scale (4-excellent,3-good,2-fair and 1-poor).The Kruskal-Wallis nonparametric test was performed for detection of differences in subjective evaluation of IQ among groups.Results The radiation doses of groups 77,66,55 and 44 mAs were 70％,55％,40％ and 25％ of the control group respectively.The differences of SNR and CNR among groups 77,66,44 mAs and the control group were statistically significant in ROI1 (F =24.018,20.386,P ＜ 0.05),SNR and CNR of group 77 and 66 mAs were higher than the control group while group 44 mAs was lower.The difference of SNR and CNR among group 55 mAs and the control group was not statistically significant in ROI1 (P ＞ 0.05).The differences of SNR and CNR among groups 77,66,55 mAs and the control group were statistically significant in ROI2 (F =15.934,13.818,P ＜ 0.05),and groups 77,66 and 55 mAs had higher SNR and CNR.The difference of SNR and CNR between group 44 mAs and the control group was not statistically significant in ROI2 (P ＞ 0.05).Groups 77,66,55 mAs and the control group had higher scores of the subjective IQ (≥ 3) which was descended in group 44 mAs.The differences of contrast,sharpness,noise and general impression of images among the 5 groups were statistically significant by Kruskal-Wallis nonparametric test(H =10.268,14.542,15.840,11.014,P ＜ 0.05).Using the criterion of excellent IQ(score 4),the ROC curve of dose levels and IQ acceptability established a reduction of 60％ of effective dose [Group 55 mAs:(3.545 ± 1.396) mSv] as an optimum cutoff point (AUC:0.844,95％ CI:0.705-0.982).Conclusions Iterative reconstruction technique could provide a dose reduction to 40％ (3.545 mSv) compared with the filtered back projection in upper limb intravascular fistula CT angiography without reducing equivalent image quality.
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Objective To explore the feasibility of low-concentration contrast agent and low-dose technology for pulmonary angiography by comparing the image quality and radiation doses to the patient by different tube voltages and concentrations of contrast agents.Methods Totally 60 patients suspected with pulmonary embolism were divided into C, L1 and L2 groups, of which,Group C had the scanning parameters of 120 kV and 350 mgI/ml,Group L1 had the parameters as 100 kV and 350 mgI/ml and Group L2 had the parameters of 100 kV and 270 mgI/ml.The three groups had the tube voltage as 500 mA, the contrast agent dose as 25 ml,physiological saline dose as 40 ml and flow rate as 4.5 ml/s.SPSS 19.0 software was used to compare and analyze the CT values of pulmonary artery segment,superior vena cava and ascending aorta,main pulmonary artery noises,the image quality as well as the radiation doses of volume scanning. Results The three groups had the main pulmonary aortas and their branches display clearly to meet clinical requirements.When compared with Group C,Group L1 had higher CT values of the main pulmonary aorta and its branches,higher image noise while lower radiation dose (P<0.01);Group L2 had equivalent CT values of the main pulmonary aorta and its branches (P>0.05),higher image noise while lower radiation dose (P<0.01).When compared with Group L1,Group L2 had lower CT values of the main pulmonary aorta and its branches (P<0.01),and equivalent image noise and radiation dose (P>0.05).Conclusion Low-concentration contrast agent and low-dose technology gains feasibility and advantages when used in 320-slice CT pulmonary angiography.
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Objective To investigate the impact of quantitative measurement for lung volume using iterative model reconstruction (IMR),hybrid iterative reconstruction (iDose4 )and filtered back projection (FBP),and to compare the image noise between different reconstruction methods.Methods 70 subjects were performed with low-dose chest CT scan (Philips Brilliance 256 iCT),and the original data were reconstructed with IMR (algorithm:Routine,SharpPlus,Soft Tissue,level:1 - 3 ),iDose4 and FBP respectively.We set less than -950 HU as emphysema threshold,calculated the total lung volume (TLV),total emphysema volume (TEV),emphysema index (EI)and objective image noise (OIN),and then compared the quantitative parameters and OIN between different groups.Results All parameters showed a significantly statistical difference (P =0.000)except TLV (P =1.000).The TEV and EI are significant higher in IMR-S group than in other groups.The OIN in IMR-S-L1 group was the highest,and the FBP group was the second-highest.OIN in iDose4 group was lower than that in IMR-S groups but higher than that in IMR-R and IMR-ST group.Conclusion SharpPlus algorithm of IMR will affect the quantitative measurement of lung volume under low-radiation-dose condition,and the OIN in IMR-S groups is obvious.Therefore SharpPlus algorithm is not recommended for quantitative analysis of lung volume.The Routine and Soft Tissue algorithm will not affect the quantitative measurement,and can distinctly reduce the OIN compared with idose4 and FBP.
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Objective To investigate the impact of quantitative measurement for lung volume using iterative model reconstruction (IMR),hybrid iterative reconstruction (iDose4 )and filtered back projection (FBP),and to compare the image noise between different reconstruction methods.Methods 70 subjects were performed with low-dose chest CT scan (Philips Brilliance 256 iCT),and the original data were reconstructed with IMR (algorithm:Routine,SharpPlus,Soft Tissue,level:1 - 3 ),iDose4 and FBP respectively.We set less than -950 HU as emphysema threshold,calculated the total lung volume (TLV),total emphysema volume (TEV),emphysema index (EI)and objective image noise (OIN),and then compared the quantitative parameters and OIN between different groups.Results All parameters showed a significantly statistical difference (P =0.000)except TLV (P =1.000).The TEV and EI are significant higher in IMR-S group than in other groups.The OIN in IMR-S-L1 group was the highest,and the FBP group was the second-highest.OIN in iDose4 group was lower than that in IMR-S groups but higher than that in IMR-R and IMR-ST group.Conclusion SharpPlus algorithm of IMR will affect the quantitative measurement of lung volume under low-radiation-dose condition,and the OIN in IMR-S groups is obvious.Therefore SharpPlus algorithm is not recommended for quantitative analysis of lung volume.The Routine and Soft Tissue algorithm will not affect the quantitative measurement,and can distinctly reduce the OIN compared with idose4 and FBP.
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Objective To investigate the feasibility of low-dose CT perfusion imaging(CTPI)examination combined with iterative model reconstruction (IMR) in the brain.Methods 80 patients with clinical suspicion of acute cerebral infarction underwent the cerebral CTPI were enrolled in this study.30 normal hemispheres on group A [35 cases,80 kV,150 mAs, filtered back projection(FBP)] and group B(45 cases,80 kV,30 mAs, IMR) were selected to evaluate respectively.The pictures' subjective scores, effective radiation dose (ED),CT value,SD,signal to noise ratio(SNR), contrast to noise ratio(CNR) and the perfusion parameters of the grey matter (GM) and white matter(WM) in each hemisphere of the middle cerebral artery(MCA) territory were respectively compared at ASPECTS level 2 for the two groups.Results The ED were 2.52,0.50 mSv for group A,B.There were no statistical significances in the perfusion parameters,CT value, SD, CNR of the ROIs of the GM and WM,the SNR of the ROIs of the GM and the pictures' subjective scores between group A, B (P>0.05).There was statistical significance in the SNR of the ROIs of the WM between group A,B (P<0.05).Conclusion IMR combined with 30 mAs of the CTPI can reduce the radiation dose apparently while maintain the stability of the image quality and perfusion parameters.
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Aim: The aim of this study was to evaluate the synergistic effect of low radiation dose with the chemotherapeutic drug in order to find possible way to lessen the harmful effects during chemo-radiotherapy. Study Design: Randomized controlled experiment. Place and Duration of Study: Experimental Animal Unit, Drug Radiation Research Department, National Center for Radiation Research and Technology, Cairo Egypt. Methodology: Estimation of antioxidant activity of low radiation dose on oxidative stress induced by cisplatin administration at a dose of 10 mg/kg b. wt. in male albino rat. Results: Results of experiment revealed that cisplatin administration caused a significant increase in serum alanine transaminase (GPT) activity (38.58±2.060) and FSH level (8.162±1.424) accompanied with a decrease in serum albumin (3.492±0.253), and Butyry Cholein Esterase (BChE) (65.35 12.61). In Liver and testis, GSH content (68.00±2.391 & 24.93±4.778) as well as cytochromes P450 levels (0.3875±0.0727 & 0.2167±0.0459) showed a significant decrease as compared to the normal control level respectively. In addition the level of Fe, Cu and Zn showed no significant changes in liver and appeared to be significantly decrease as in case of corresponding trace elements in testis organs. On the other hand, exposing to low dose of radiation (0.5 Gy) post-cisplatin treatment effectively prevented these alterations and maintained the antioxidant status. Conclusion: Data from present results revealed that low radiation dose have the existence as an antioxidant and antitumor agents which may be useful to use as a synergistic agents with the chemotherapeutic drug.
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Objective To study the feasibility of reducing radiation dose in aorto-iliac and lower extremity arteries CT angiography (CTA) with low tube voltage (100 kV) and automatic tube current modulation(ATCM).Methods Totally 61 patients requiting aorto-iliac and lower extremity arteries CTA for clinical reasons were prospectively enrolled in study.The patients were randomly assigned to 3 groups:Group A(120 kV),Group B (100 kV) and Group C (100 kV with automatic tube current modulation).Both quantitative and qualitative analysis were included in this research.Group C was divided into obese group(BMI≥ 24.9 kg/m2) and normal group(BMI ＜ 24.9 kg/m2).The radiation doses were analyzed respectively among two groups.Results The subjective evaluations of image quality for axial,MIP and VR were good.There were no significant differences among group A,B and C in SNR and CNR (P ＞0.05).The effective dose of group A,B and C was 8.20 mSv,5.36 mSv,and was 7.48 mSv,respectively Group B was 34.6％ less than group A.Group C was 39.5％ more than group B,and there was no significant differences between group A and C (P ＞ 0.05).The effective dose of group C1 was 7.11mSv,group C2 was 9.69 mSv,the E with group C1 were significantly less than group C2 (t =-3.163,P ＜0.05),the effective dose of group C1 was 13.3％ less than group A (Z =-2.822,P ＜ 0.05),but the group C2 was more than group A (P ＞ 0.05) and group B (Z =-3.426,P ＜ 0.05).Conclusions Lowkilovoltage (100 kV) CT scanning protocol is feasible in multi-detector CT angiography for aortoiliac and lower extremity arteries.Automatic low tube voltage (100 kV) with automatic tube current modulation (ATCM) scanning protocol can be used for someone with BMI less than 24.9 kg/m2.