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Objective:To investigate the predictive value of stone composition prediction method based on dual-source stone energy spectrum CT for uric acid stones.Methods:The clinical data of 204 patients with urinary stones, 159 males and 45 females, admitted to Shanghai Sixth People's Hospital from July 2020 to July 2022 were retrospectively analyzed. The average age was (50.7±14.3) years. There were 187 cases of upper urinary tract (kidney, ureter) stones and 17 cases of lower urinary tract (bladder, urethra) stones. All patients underwent preoperative dual-source stone energy spectroscopy CT, measuring CT values at 150 kV and 100 kV, respectively, and the calculated dual energy ratio (Ratio) was used to predict stone composition. Of the 204 cases in this group, 33 cases underwent percutaneous nephrolithotomy and 171 cases underwent ureteroscopic lithotripsy. Postoperative stone specimens were analyzed for stone composition by infrared spectroscopy. Subject work characteristic (ROC) curves were used to analyze the efficacy of preoperative dual-source stone energy spectrum CT to predict uric acid stones.Results:In 204 patients, preoperative CT predicted 28 cases of uric acid stones and 176 cases of non-uric acid stones, including 136 cases of calcium oxalate stones, 38 cases of hydroxyapatite, and 2 cases of cystine stones. Postoperative IR spectral analysis detected 26 cases of uric acid stones and 178 cases of non-uric acid stones, including 129 cases of calcium oxalate stones, 47 cases of hydroxyapatite, and 2 cases of cystine stones. Compared with the preoperative CT results, there were 2 false positives and no false negatives in the classification of uric acid stones. The ROC curve showed that the sensitivity of the CT value for predicting uric acid stones at 100 kV was 96.2%, the specificity was 99.5%, and the area under the ROC curve (AUC) was 0.995, with the best prediction value of 620 HU.The sensitivity of the CT value for predicting uric acid stones at 150 kV was 96.2%, specificity was 85.5%, AUC was 0.916, and the best predictive value was 597.5 HU. The sensitivity of using Ratio values for predicting uric acid stones was 100.0%, specificity was 97.9%, AUC was 0.996, and the best predictive value was 1.14. The CT values for uric acid stones at 100 kV and 150 kV were (558.58±77.07) HU and (521.12±83.54) HU, CT values for calcium oxalate stones were (1 335.26±301.82) HU and (878.21±200.21) HU, CT values for hydroxyapatite were (1 104.09±203.61) HU and (710.38±178.44) HU, respectively.The CT values of cystine stones were (684.5±67.18) HU and (573.5±67.10) HU, respectively, and the differences between uric acid stones and other components were statistically significant ( P<0.01). The Ratio values of uric acid stones, calcium oxalate stones, hydroxyapatite, and cystine stones were 1.08±0.06, 1.52±0.08, 1.62±0.40, and 1.19±0.02, respectively, and the differences were statistically significant ( P<0.01) when comparing uric acid stones with other components. Conclusion:The CT and Ratio values of dual-source stone energy spectrum CT can effectively distinguish uric acid stones from other types of stones, and the accuracy, sensitivity, and specificity of this method for predicting uric acid stones are high.
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Objective To discuss 7Be and a 77.2 keV full-energy peak with short half-life found in the water sample from the 3D water phantom of a proton therapy system. Methods We measured the water sample from the 3D water phantom of a proton therapy system according to Determination of Radionuclides in Water by Gamma Spectrometry (GB/T 16140—2018). Results The activity concentration of 7Be in the water sample was 1.30 × 101 Bq·L−1 on December 24, 2018; 4.3 × 101 Bq·L−1 on March 22, 2019; and 1.41 × 101 Bq·L−1 at the time of sampling on December 19, 2018. On December 24, 2018, the net peak area of the 77.2 keV full-energy peak in the sample was 683 ± 45, and the measurement time was 26123.02 s; on March 22, 2019, the net peak area decreased to the background level of 194 ± 49, and the measurement time was 86400.00 s. Conclusion In the 3D water phantom of the proton therapy system, 7Be can be generated from the spallation reaction between high-energy neutrons and oxygen in water. In addition, we find a full-energy peak at 77.2 keV with short half-life. The activity concentration of 7Be in the water sample is lower than the exemption level, but the activity concentration at sampling may not be the maximum activity concentration in the process of quality control. The inductive radionuclide 7Be produced in the 3D water phantom should be identified and properly evaluated in the assessment of occupational radiation hazards of proton therapy system.
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Objective To compare the differences of energy spectrum CT between small cell lung cancer(SCLC)with mediastinal lymph node metastasis and mediastinal sarcoidosis.Methods Twenty-five SCLC patients with mediastinal lymph node metastasis(SCLC group)and 26 patients with mediastinal sarcoidosis(sarcoidosis group)confirmed by bronchoscopy and biopsy in Tangshan People's Hospital from January 2018 to June 2019 were selected as the research objects.The CT value,iodine concentration,water concentration and energy spectrum curve slope under different single energy levels were compared between SCLC group and sarcoidosis group.Results The single-energy CT values of 40-80 keV segments in the arterial phase of the SCLC group were significantly higher than those in the sarcoidosis group(all P 0.05).The single-energy CT values of 40-90 keV segments in venous phase of the SCLC group were significantly higher than those of the sarcoidosis group(all P 0.05).The concentrations of iodine in the arterial phase and venous phase of the SCLC group were(11.56±4.06)μg/cm
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Humans , Lung Neoplasms/diagnostic imaging , Lymph Nodes , Lymphatic Metastasis , Sarcoidosis/diagnostic imaging , Small Cell Lung Carcinoma/diagnostic imaging , Tomography, X-Ray ComputedABSTRACT
Objective The experiment project was designed to explore the variation of NaI (Tl) gamma spectrometer channels with environmental temperature. 60Co and 152Eu were used to verify the reliability of the correction methods. Methods Two correction methods were applicated, which were curve fitting correction method and known measurement peak correction method. Results The experimental results showed that temperature changes had an effect on NaI (Tl) measured spectra peak. The relative peak will shift to the right at 5℃ by 9.6%, and to the left at 60℃ by 16%, with the reference temperature set at 25℃. The two methods are based on the channel change due to temperature changes, and they could effectively correct the temperature peak-drift. Conclusion In order to make the measured spectrum information accurate and reliable in field monitoring, it is suggested to monitor the environmental temperature so as to correct the measured data.
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Objective:To explore the application value of single source dual energy CT (DECT) scanning technique in improving the image quality of the pancreas.Methods:Imaging data of 21 patients with normal pancreas and 36 patients with pancreas related diseases in the First Affiliated Hospital of Naval Medical University from July 2021 to August 2021 were collected. All the patients first underwent multi-slice CT (MDCT) scan with no-contrast, and then dynamic enhanced MDCT scan. And the DECT scan was used in the delay period. Virtual single energy images (VMI, 40~100keV) of normal pancreas and mixed energy images of pancreatic lesions (PI, 80 and 140kVp) were obtained. The regions of interest (ROI) of fat on abdominal wall, normal pancreas and abdominal aorta were delineated, the CT values and standard deviation (SD) of each ROI were measured and recorded, and the pancreatic signal-to-noise ratio (SNR) and contrast-to-noise ratio (SNR) of each energy image were calculated. The objective index and subjective score of VMI(40-100keV) and PI (80kVp and 140kVp) with iodine (water) base map and VMI best CNR were compared between groups. The correlation between VMI(40-100keV) and PI(80, 140kVp) with iodine (water) base map and VMIbest CNR was analyzed by univariate regression.Results:In VMI(40-100keV) of normal pancreas, the highest SNR value was VMI best CNR and iodine (water) base map, and the highest CNR values were VMI 60keV and iodine (water) base map. There were significant differences on SNR and CNR values between different energy VMI and iodine (water) base map ( P<0.05). Among the four images of PI 80kVp, PI 140kVp, VMI best CNR and iodine (water) base map for pancreatic lesions, the SNR and CNR values of iodine (water) base map were the highest. The SNR and CNR values of VMI best CNR were higher than those of PI 80kVp, and the differences were statistically significant ( P<0.05). The lesion significance and edge sharpness score of iodine (water) base map was the highest, which was better than other groups; the lesion significance and edge sharpness score of VMI best CNR was better than PI 140kVp, and the differences were statistically significant ( P<0.05). The results of univariate regression analysis showed that the SNR values of PI 80kVp, PI 140kVp and VMI best CNR for pancreatic lesions were positively correlated with those of the iodine (water) base map ( P<0.05), the CNR values of PI 140kVp and VMI best CNR images were positively correlated with the iodine (water) base map ( P<0.05), and the SNR and CNR values of PI 140kVp were positively correlated with VMI best CNR ( P<0.05). Conclusions:VMI with different energy and iodine (water) base maps can be obtained by single source DECT enhanced scanning of pancreas related diseases. The VMI best CNR was the best among all VMIs, while the SNR and CNR values of iodine (water) base maps were the highest in all images. The VMI best CNR and iodine (water) base maps can improve the image quality of pancreas related diseases.
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BACKGROUND: Ilizarov technique has obvious advantages in the treatment of tibial bone defect and can be used to treat various types of tibial bone defect. However, there are still many shortcomings in this technology, which need to be solved urgently. OBJECTIVE: To review the advantages, shortcomings and improvement strategies of Ilizarov technique in the treatment of tibia bone defect. METHODS: PubMed, CNKI and Wanfang databases from 1971 to 2019 were retrieved with the key words of “bone defect, bone transport, accordion maneuver, ultrasonography, energy spectrum CT, pin site infection” in English and Chinese, respectively. Totally 57 eligible articles were included to systematically summarize the advantages, shortcomings and improvement strategies of Ilizarov technique in the treatment of tibia bone defect. RESULTS AND CONCLUSION: (1) Ilizarov technology has obvious advantages in the treatment of the tibia bone defect, combined with soft tissue injury, infection and deformity of the tibia bone defect. (2) New disinfectants, accordion technology, color Doppler ultrasound and energy spectrum CT are effective treatment methods for complications of bone transport technology, such as pin site infection, poor mineralization of new bone in the transfer area, and difficulty in healing at the docking site. These methods can reduce the incidence of complications. (3) It is still necessary to improve the existing treatment techniques or choose new methods to further reduce the incidence of complications.
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Objective To compare monitoring value of energy spectrum CT and ultrasound in bone transport process. Methods Eighteen patients who underwent bone transport were examined with energy spectrum CT and ultrasonography at the 2nd, 4th, 6th week and 8th week after surgery, and the construction of lateral callus, the formation of callus in the intramedullary cavity, the range of organized hematoma and the nature of the vesicular area were observed, the length of bone extension area and organized hematoma were measured. The radiation dose of energy spectrum CT scan was also calculated. Results Primary callus structures were observed on CT and ultrasound at the 2nd to 8th week after surgery, and the callus and cortical bone could not be distinguished by ultrasound at the 8th weeks. At the 2nd to 8th week after surgery, both CT and ultrasound could observe the range of organized hematoma and the increased quantity of callus in the intramedullary cavity. There was no statistically significant difference of the length of systemic hematoma nor bone extension area measured with CT and ultrasound at the 2nd and 4th week after surgery (all P>0.05), while significant difference was detected in the length of systemic hematoma and bone extension area measured at the 6th weeks after surgery (both P0.05), while CT energy spectrum curve could identify the nature of fluid vesicles. The effective radiation dose of energy spectrum CT was (0.71±0.71)mSv. Conclusion Energy spectrum CT and ultrasound both have advantages in monitoring the formation of regenerated tissue during bone transport. Energy spectrum technology can be used as a new monitoring method.
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Objective To investigate the minimum dose of contrast medium when using spectral CT in cranial CTA. Methods Three groups of patients were required to undergo head CTA examination because of their condition,but different doses of contrast agents were injected.Among them,group 30 mL, group B, group 40mL, group C and group 50 mL were A. Results In group A,the lowest rate of excellent image (23.33%), B group, C group had higher rate of excellent image (93.33%, 96.67%), comparison of the data P<0.05; C group the highest rate of adverse reaction of contrast agent (P<0.05),data comparison P<0.05, A group, B group significantly adverse reactions of contrast agent there is no difference between the situation (P>0.05). Conclusion The use of 40 mL iodide contrast medium in the procedure of cranial CTA examination is effective and safe.
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Objective To investigate the minimum dose of contrast medium when using spectral CT in cranial CTA. Methods Three groups of patients were required to undergo head CTA examination because of their condition,but different doses of contrast agents were injected.Among them,group 30 mL, group B, group 40mL, group C and group 50 mL were A. Results In group A,the lowest rate of excellent image (23.33%), B group, C group had higher rate of excellent image (93.33%, 96.67%), comparison of the data P<0.05; C group the highest rate of adverse reaction of contrast agent (P<0.05),data comparison P<0.05, A group, B group significantly adverse reactions of contrast agent there is no difference between the situation (P>0.05). Conclusion The use of 40 mL iodide contrast medium in the procedure of cranial CTA examination is effective and safe.
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Objective:To discuss the effect of different reconstruction algorithms for the image quality of the computed tomographic angiography (CTA) with low dose on head and neck through comparing the images obtained from different reconstruction algorithms, which included filtering and reflection projection technique (FBP), adaptive statistical iterative (ASIR) model and based on iterative reconstruction (MBIR) after CTA with low dose was applied on head and neck.Methods:30 patients who were implemented the CTA on head and neck were enrolled in this study. The gem energy spectrum CT was applied to scan their head and neck, and the tube voltage was set in low dose (80 kVp), and 60-80 mL contrast agent (350 mg I/mL) was injected in elbow vein as 4mL/s. The other parameters were chosen as routine requirement. The obtained original images were reconstructed by using FBP, 60% ASIR and MBIR, and then the three kinds images were compared and scored by using relative statistical analysis.Results: For the using of different reconstruction algorithms (FBP, 60% ASIR and MBIR), the results of image noise showed MBIR60% ASIR>FBP, and the differences among them were significant. Finally, about the subjective score of image, the results showed MBIR>60% ASIR>FBP, and their differences also were significant.Conclusion: Under gem energy spectrum CT, the image noise of MBIR is lowest and its image quality is best, and it has diagnosis value and meaning in clinical practice.
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Objective To determine the utility of single energy CT value and spectrum energy curve in identifying different cause of diffuse spleen enlargement.Methods 43 patients confirmed by either surgical pathology,aspiration biopsy or clinical comprehensive diagnosis and follow-up were assessed,including lymphoma with spleen infiltration(lymphoma group,n=18) and cirrhotic splenomegaly(liver cirrhosis group,n=25).All patients underwent upper abdomen CT scans in GSI mode and the GSI data were transferred to the Workstation AW 4.6 to acquire single energy CT value(40-140 keV,10 keV's interval) and spectrum energy curve of the spleen on the venous phase.All single energy CT values and the slope of curves were comparatively analyzed through independent-samples t test.The diagnostic efficiency were evaluated by ROC analysis.Results Under 40-140 keV energy range,single energy CT values were significantly lower in the lymphoma group than in the liver cirrhosis group(all P＜0.05).The spectrum energy curve were both types of decreasing.Under 40-90 keV,100-140 keV energy range,the slop of curves in the lymphoma group(2.42 ± 0.70,0.27± 0.08) were also significantly lower than in the liver cirrhosis group (3.11 ± 0.62,0.34± 0.07),respectively(all P ＜0.05).When the slope of curve under 40-90 keV energy range was selected as a diagnostic indicator,the area under the curve(AUC) would reach 0.77.If threshold value of 1.39 was taken,the sensitivity and specificity would be equal to 86 ％ and 64 ％,respectively.Conclusion Single energy CT value and spectrum energy curve are helpful for differentiation of lymphoma with spleen infiltration from cirrhotic splenomegaly.
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Objective To validate the feasibility of the simulationmethod and the reliability of thesimulationresult through comparison between simulation and measurement of the energy spectrum from medical diagnostic X-ray (RQR-Radiation qualities in radiation beans emerging from the X-ray source assembly).Methods A simplified model of the medical diagnostic X-ray RQR radiation quality was established using code of BEAMnrc.The energy spectrum of the same RQR radiation quality were measured through a plane high-purity germanium spectrometer,and compared with the simulationresult.Results The difference of spectral distribution between measurement and simulation was less than 3％,in spite of the convolution processing not happened to the pulse height distribution measured by the spectrometer.And the spectral distribution,fluence,energy fluence,means energy distribution of the radiation was obtained using the code of BEAMDP.Conclusions As indicated above,it is possible to use the simulation of the energy distribution as a foundation for the establishment of X-ray RQR radiation quality.
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Objective To investigate the relationship between the single energy CT value and the tissue density and further evaluate the mass of thyroid.Methods Different substances respectively composed of liquid and solid,liquid and liquid,thyroid gland were selected,and the relationship was investigated between the single energy CT value and the tissue density.Results The CT value was closely related to the content of high atomic number substance.The CT value of thyroid was closely related to the content of iodine.Conclusion It is feasible to measure the thyroid density by the energy spectrum CT.
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Objective To evaluate the application value with Energy Spectrum CT multi -parameter quanti-tative value in differentiating pulmonary occupying lesions (>0.5cm in diameter).Methods Those were retrospec-tively analyzed on 58 cases in pulmonary occupying lesions performed spectrum dual -phase enhanced CT scan and confirmed by pathology,including malignant group 48 cases;10 cases of benign group.Iodine content(IC)was meas-ured in arterial phase(AP)and venous phase (VP)in iodine based on the image and the level of the aorta,and nor-malized iodine concentrations were calculated in the two phases lesions compared with aorta,and the difference between the two normalized iodine concentrations ICD (ICD =NICvp -NICap).To measure the CT value of lesions on 50keV and 100keV energy image,and calculate the energy attenuation curve slope,namely |Hu (100 kev -50kev)/Hu50 |.The differences of NIC,curve slope,and ICD were compared between benign and malignant pulmonary occupying lesions using independent sample t test method.Results In two phase scan,NIC,curve slope of the venous phase and ICD in malignant group were significantly higher than the benign group,(NIC,curve slope of the venous phase and ICD of the malignant group:NICap:0.180 ±0.051,NICvp:0.463 ±0.086,1.696 ±0.475,ICD:0.284 ± 0.071;NIC,curve slope of the venous phase and ICD of the benign group:NICap:0.123 ±0.062,NICvp:0.290 ± 0.119,1.169 ±0.582,ICD:0.166 ±0.073,),but there was no significant difference between the patients with benign and malignant lesions in curve slope of the arterial phase.Conclusion Energy spectrum CT dual -phase enhanced scan can differentiate the nature of benign and malignant pulmonary occupying lesions,and has certain clinical application value.
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Objective To establish a novel Monte Carlo simulation method for reconstruction of medical accelerator model and X?ray energy spectrum based on IAEA Varian 6 MV X?ray phase?space file and photon energy spectrum of the target accelerator. Methods The verified 6 MV X?ray phase?space files were preprocessed to elevate the energy of each particle. Particles were saved in different Phase?Space?Let ( PSL) files according to their position and energy, yielding an initial photon energy spectrum for Monte Carlo simulation of accelerator under an initial target energy. The initial photon energy spectrum was fit to a photon energy spectrum of an accelerator ( Elekta Precise 10 MV X?ray accelerator) under an unknown target energy to yield a fitting coefficient, which was the weight of each PSL. Finally, an accelerator model under an unknown target energy was reconstructed using the initial PSL files and the weight information. The percentage depth dose ( PDD) distribution was calculated in different square open fields. The effectiveness of this method was verified using one dimensional gamma passing rate. Results The peak position and overall distribution of the reconstructed 10 MV photon energy spectrum were in accordance with those of the verified 10 MV photon energy spectrum. The PDD calculated from the reconstructed 10 MV accelerator model agreed well with the measured PDD. The one?dimensional gamma passing rate was above 96%( 1%/1 mm, threshold=0%) . Conclusion The Monte Carlo reconstruction method proposed in this study is reliable, accurate, and effective.
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Objective To study the spectrum structure of X-ray and simplify the description method of it. Methods By the general program of Monte Carlo Geant4 to study X-ray spectrum structure and angular distribution of X-ray energy spectrum. Results The results of percentage depth doses and profile curves at different depths of any radiation fields in water phantom calculated by Monte Carlo Geant4 were consistent with the measurements. Conclusions In radiotherapy, X-ray with same nominal energy have very similar dosimetry characteristics, this indicates they have very similar energy spectrum and angular distribution of spectrum. the differences of dosimetric details reflect the different details of the X-ray spectrum structure and angular distribution of X-ray energy spectrum. These studies have very important significances to rapidly build precise virtual source modeling for Monte Carlo calculation based on dose curves measurements in water phantom.
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Recent radiotherapy dose planning system (RTPS) generally adapted the kernel beam using the convolution method for computation of tissue dose. To get a depth and profile dose in a given depth concerened a given photon beam, the energy spectrum was reconstructed from the attenuation dose of transmission of filter through iterative numerical analysis. The experiments were performed with 15 MV X rays (Oncor, Siemens) and ionization chamber (0.125 cc, PTW) for measurements of filter transmitted dose. The energy spectrum of 15 MV X-rays was determined from attenuated dose of lead filter transmission from 0.51 cm to 8.04 cm with energy interval 0.25 MeV. In the results, the peak flux revealed at 3.75 MeV and mean energy of 15 MV X rays was 4.639 MeV in this experiments. The results of transmitted dose of lead filter showed within 0.6% in average but maximum 2.5% discrepancy in a 5 cm thickness of lead filter. Since the tissue dose is highly depend on the its energy, the lateral dose are delivered from the lateral spread of energy fluence through flattening filter shape as tangent 0.075 and 0.125 which showed 4.211 MeV and 3.906 MeV. In this experiments, analyzed the energy spectrum has applied to obtain the percent depth dose of RTPS (XiO, Version 4.3.1, CMS). The generated percent depth dose from 6x6 cm2 of field to 30x30 cm2 showed very close to that of experimental measurement within 1% discrepancy in average. The computed dose profile were within 1% discrepancy to measurement in field size 10x10 cm, however, the large field sizes were obtained within 2% uncertainty. The resulting algorithm produced x-ray spectrum that match both quality and quantity with small discrepancy in this experiments.
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Particle Accelerators , UncertaintyABSTRACT
The photon energy spectrum of KRISS 60Co irradiation system (AECL Eldorado 8) was calculated by means of the Monte Carlo method. The collimators were modeled realistically, and the material and dimensions of the 60Co sealed source were extracted from the source certificate given by the manufacturer. It was confirmed that the photon energy spectrum of KRISS 60Co irradiation system was in similar shape with those of NRC and BIPM.
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Monte Carlo MethodABSTRACT
The Compound Bioceramic (CBC),a newly developed artificial bone material,were im- planted in the man-made defects on madibular bodies of four dogs.The an imals were sacri- ficed three months later.The specimens were prepared by routine procedures.The interfaces between the CBC materials and bones were studied by electromicroscope scanning and X-ray energy spectrum analysis:the results showed that the CBC materials could be bioconnected with bones (osseous bond as was called).The study suggested that the osseous bond mecha- nism of the CBC material be related to the ion migration and deposition of calcium and phosphate on the interfaces.
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Objective After the rabbits were electrocuted by 220V AC,we found that the pathological changes in the surface of the bones electrocuted could be one objective and quantitative index for the diagnosis of electrocution in the forensic pathology.Methods The experiment animals were divided into four groups,including: the antemortem electrical injury,postmortem electrical injury,putrefied and the normal.After specimens from each group being taken X ray examination,all specimens were then observed the morphological appearance of the surface of the bones with scanning electron microscopy(SEM),meanwhile,detected the kinds and contents of element in the electrical injury area with energy spectrum.Results①small holes on the surface of electrified area and the detection of contents of the elements in the high-density surrounding the holes could be a index for the diagnosis of AC injury and able to differentiate of the antemortem electrical injury,the postmortem electrical injury and the putrefied bones.②the morphologic changes of small holes and the alteration of the contents of elements such as calcium,phosphorus and carbon could be helpful to estimate the time of electrical injury.Conclusion The morphological appearances and the changes of elements in the surface of the bones electrocuted could be a useful index to analyse the differences among the antemortem electrical injury,postmortem electrical injury,putrefied and the normal bones.