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OBJECTIVE@#To investigate the effects of on the acoustic characteristics of tumor tissue and how such acoustic changes affect the efficacy of high-intensity focused ultrasound (HIFU) ablation in nude mice.@*METHODS@#Forty mice bearing human breast cancer cell (MDA-MB-231) xenograft were randomized into experimental group (=20) and control group (=20) for intravenous injection of suspension (200 μL, 4 × 10 cfu/mL) and PBS (200 μL) for 3 consecutive days, respectively. Before and at 3 and 7 days after the first injection, shear wave elastography was used to evaluate the hardness of the tumor tissue. On day 7 after the first injection, 10 mice from each group were sacrificed and the sound velocity and sound attenuation of the tumor tissues were measured. The changes in the collagen fibers in the tumors were evaluated using Masson staining, and neovascularization in the tumor was assessed with immunohistochemistry for platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31). The remaining 10 tumor-bearing mice in each group were subjected to HIFU ablation, and the ablation efficiency was evaluated by assessing the changes in irradiation gray values, coagulative necrosis volume, energy efficiency factor (EEF) and irradiation area and by pathological examination with HE staining.@*RESULTS@#In the experimental group, the collagen fibers in the tumor tissues were strong and densely aligned, and the tumors contained fewer new blood vessels showing strip-or spot-like morphologies. In the control group, the collagen fibers in the tumors were thin and loosely arranged, and the tumors showed abundant elongated or round new blood vessels. colonized in the tumor 7 days after the injection, and the tumor hardness was significantly greater in the experimental group than in the control group (=0.01); the acoustic velocity (=0.001) and the acoustic attenuation (=0.000) of the tumor tissues were also greater in the experimental group. HIFU irradiation resulted in significantly greater changes in the gray scale of tumor (=0.0006) and larger coagulative necrosis volume (=0.0045) in the experimental group than in the control group, and the EEF was significantly smaller in the experimental group (=0.0134).@*CONCLUSIONS@# can cause changes in collagen fiber content, acoustic velocity and attenuation in the tumor tissue and reduce the EEF of HIFU irradiation, thereby improving the efficacy of HIFU irradiation.
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Animals , Humans , Mice , Acoustics , Bifidobacterium , Virulence , Breast Neoplasms , Pathology , Collagen , Elasticity Imaging Techniques , High-Intensity Focused Ultrasound Ablation , Mice, Nude , Neoplasm Transplantation , Random AllocationABSTRACT
Objective To explore the impact of different angles between blood vessels and acoustic axis in the target area on pulse high intensity focused ultrasound (PHIFU) peripheral ablation.Methods Thirty New Zealand rabbits were selected,and the thoracic aortas were obtained.Models of tissue mimicking material were used via embedding the rabbit thoracic aorta into the center of the target barrier area.Then the models were divided into 0°,45° and 90° groups according to the angles with the acoustic axis,and the control group was set up as well (each n =10).Under B-ultrasound monitoring,PHIFU peripheral ablation was performed with the same parameters in each group.The temperature was measured during ablation.After ablation,the models were cut step by step for macroscopic and ultrasound observation.The total volumes (V) were calculated and compared,and the target blood vessels were sampled for pathological examination.Results The peripheral region in control group showed strong echo on ultrasound image,while in 0°,45° and 90° group the blood vessels showed low echo accordingly.The maximal temperatures in control group,0°,45° and 90° group was (98.60 ± 5.76) ℃,(98.90 ± 7.09) ℃,(71.10 ± 13.85) ℃ and (70.20 ± 9.14) ℃,respectively.Statisticaldifference was found between control group and 45°,90° group (all P＜0.05).The total volume in control group,0°,45° and 90° group was (40 709.70 ± 3 193.31) mm3,(40 029.02 ± 3 580.17) mm3,(34 562.59 ± 3 883.26) mm3 and (36 737.01± 3 278.68)mm3,respectively,while no statistical difference was found between control group and 0° group (P＞0.05).Pathological examination showed that the elastic fibers fractured partly,and disruption of cell nucleus were observed in 45° and 90° group.Conclusion When the angle between the blood vessel and acoustic axis is 0°,its impact on energy deposition is minimally,while the destruction of the vascular wall becomes stronger when the angle is 45°and 90°.
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Objective To investigate the effect of blood vessels at different locations and angles between blood vessel and sonic axis within the target area on HIFU peripheral ablation.Methods Totally 56 phantoms containing rabbit thoracic a orta were divided into group A (different vessel locations) and B (different vessel angles).According to the distance (d)between the blood vessel center and the deepest (top) layer of the peripheral scanning,group A was divided into A1 (d=0),A2 (d=10 mm),A3 (d=20 mm) subgroups.According to the angle (α) between the vessel long axis and the acoustic axis,group B was divided into B1 (α=0-5°),B2(α=60° 65°),B3 (α=90°-95°),B4 (α=115°-120°) subgroups.A4,B5 subgroups were set as the control groups.The vessel diameter and vessel wall thickness were measured.The lesion morphology was observed and the energy efficiency factor (EEF) was calculated.Results There was no significant difference in vessel diameter and vessel wall thickness in both group A and B (all P＞0.05).There was no residual area in the target area of A1,B1 subgroup,while there was residual area in the target area of the other subgroups.EEF of group A in ascending order were A4,A1,A2 subgroup,and statistically significant differences in pairwise comparisons (all P＜0.05) except for A1 and A3 subgroup (P＞0.05).EEF of group B in ascending order were B5,B2,B3 subgroup,respectively,and statistically significant differences in pairwise comparisons (all P＜0.05) except for B2 and B4,B5 and B1 subgroup (both P＞0.05).Conclusion It is 10 mm that the distance between the blood vessel center and the deepest (top) layer of the pe ripheral scanning,and 90°-95° that the angle between the vessel long axis and the acoustic axis has the greatest influence on the ablation of the target area.
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Objective To discusse the influence of permeating perfluoropentane drops-encapsulated mesoporous silica nanocapsules (MSNC-PFP) on HIFU surface ablation in vitro bovine liver.Methods Fifity bovine liver tissues were divided into 5 groups:Control group,0.25 mg/ml group,0.50 mg/ml group,1.00 mg/ml group,2.00 mg/ml group according to the concentration of MSNC-PFP.The synergistic agent was injected along the ablation line path under the guiding of ultrasound.The surface ablation model was structured by 6 coagulation necrosis side by using HIFU linear scanning,inner region without melting,and the ultrasonographic changes were observed in the melt area.The coagulation necrosis range was assessed by TTC staining,and necrosis degree was observed by HE staining.The coagulation necrosis volume was measured,the coverage index (CI),external volume index (EI),energy efficiency factor (EEF) were used to evaluate the ablation effect in each group.Results The MSNC-PFP more than 1.00 mg/ml was shown as strong echo in ultrasonic image,fade after 3-5 min.The grey value was changed in HIFU ablation area related to the concentration of MSNC-PFP.The total ablation volume of 0.50 mg/ml group,1.00 mg/ml group,2.00 mg/ml group were more than control group,the EEF was lower than that of the control group (all P＜0.01).The CI and EI of 1.00 mg/ml group and 2.00 mg/ml group were higher than those of the other group (all P＜0.01).The coagulation necrosis became complete when the concentration of MSNC-PFP above 0.50 mg/ml.Conclusion MSNC-PFP can increase the volume of coagulation necrosis,decrease the EEF and increase the efficiency of HIFU surface ablation of bovine liver in vitro.
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Guided by the demands of society,we have conducted a survey involving job distribution data,knowledge structure,curriculum setting,practical ability and innovation ability training on graduates,and made the investigation and discussion of graduates' quality and social needs.And according to the feedbacks,we have carried out the reform of Biomedical Engineering by insisting on the management philosophy and characteristics of student-centre and the combination of medical science with engineering,making the training goal definite further,constructing a curricula system of the combination of medical science with engineering,outstanding engineering characteristics and strengthening students' engineering practice ability,and carrying out innovation and entrepreneurship education through the whole process of teaching,to improve the teaching quality of Biomedical Engineering specialty.
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Objective To investigate the feasibility and effectiveness of focused ultrasound on the acne of rabbit ear.Methods Eighteen male rabbits were randomly divided into blank control group,model control group and ultrasound irradiation group.Acne rabbit ear model was established by Kligman's method in model control group and ultrasound irradiation group.Then,continuous ultrasonic irradiation was given in ultrasound irradiation group.Pathological changes were observed at the time of before and after ultrasound irradiation and 14 days after ultrasound irradiation.Results After modeling,hair follicle expansion,hyperkeratosis,acupoint hypertrophy were observed in blank control group.Compared with blank control group,the thickness of horn layer,the sebaceous gland diameter and other index in model controlgroup were statistically significant (P＜0.01);After irradiation,there were hyperemia and edema in epidermis,angiotelectasis and inflammatory infiltrating,but coagulative necrosis in slice was not observed,14 days later,hair follicle mild expansion,mild keratosis,spiny thinning were observed in ultrasound irradiation group,when compared with model control group,the thickness of horn layer,sebaceous gland diameter and other index were decreased in ultrasound irradiation group,and the differences were statistically significant(P＜0.01).Conclusion The ultrasonic focusing treatment on rabbit ear acne is feasible and effective.
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In order to improve students' overall quality,Biomedical Engineering College of Chongqing Medical University has carried out quality development training in the 6 session of the 450 students.The content includes development projects,the queue training,humanities lectures,inspirational film etc.; the objective is to develop the students' mind,develop their team spirit and interpersonal communication skills.College has recruited and assisted professional instructors in the whole training.The centralized training in specific situations gives students a strong spiritual shock and strong positive energy.Before and after the training we use the same questionnaire to students,the results of which have shown that their comprehensive ability,EQ,and cohesion of the class have been improved.
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This paper discussed on the innovative efforts of establishing production-teaching-research platform and multi-channel international cooperation model by Chongqing Medical University. Measures taken included offering theoretical courses across the first-level disciplines of medicine and engineering and encouraging research tasks that involve the cooperation among hospitals , businesses and universities, creating education environment for postgraduates combing medicine and engineering and launching the cultivation of biomedical engineering postgraduates. The aim of these measures was to incorporate the achievements of scientific research innovation into postgraduate education and to improve its quality.
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<p><b>OBJECTIVE</b>To investigate the accuracy of ultrasound monitoring during pulsed high intensity focused ultrasound (PHIFU) treatment and improve the sensitivity of ultrasound monitoring of tissue necrosis caused by PHIFU treatment.</p><p><b>METHODS</b>Bovine liver ex vivo was dot-exposed with HIFU at the therapeutic doses of 2000 J (group A) and 1440 J (group B). The two groups were further divided into groups A1 (power 100 W, duty cycle 100%, irradiate 20 s) A2 (power 100 W, duty cycle 50%, irradiate 40 s), A3 (power 100 W, duty cycle 40%, irradiate 50 s), B1 (power 120 W, duty cycle 100%, irradiate 12 s), B2 (power 100 W, duty cycle 50%, irradiate 24 s), and B3 (power 100 W, duty cycle 40%, irradiate 30 s). The gray scale changes in the ultrasonic images after the exposures were observed, and the correlation function of the image was calculated before and after the exposure. The accuracy of evaluations based on the correlation function and gray-scale changes was compared.</p><p><b>RESULTS</b>The correct rate of gray scale-based evaluation of tissue necrosis caused by PHIFU was only 51%, while that by correlation function-based evaluation reached 85%.</p><p><b>CONCLUSION</b>Monitoring of tissue necrosis caused by PHIFU treatment can not rely solely on evaluation of gray-scale change of the ultrasound images, and the correlation function-based evaluation can be more accurate and sensitive for that purpose.</p>
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Animals , Cattle , High-Intensity Focused Ultrasound Ablation , Methods , In Vitro Techniques , Likelihood Functions , Liver , Diagnostic Imaging , UltrasonographyABSTRACT
<p><b>OBJECTIVE</b>To compare the effect of ablations with pulsed and continuous high-intensity focused ultrasound (HIFU) on the target area containing large blood vessels in isolated perfused porcine liver.</p><p><b>METHODS</b>An isolated perfused liver model was established by perfusing the isolated porcine liver with autologous blood through the portal vein and hepatic artery using an cardiopulmonary bypass machine. With B-mode ultrasound guidance, a blood vessel about 4 mm in diameter was selected, and pulsed and continuous HIFU ablation at the same dose was delivered along the blood vessel at 3 mm to the vascular wall. After the ablation, the damages of the blood vessels as the acoustic channel and the target area were inspected, and the tissues at the interface of target volume and blood vessels were sampled for pathological examination.</p><p><b>RESULTS</b>Neither pulsed nor continuous HIFU caused noticeable injuries of the acoustic channel vessels, but the volume of necrotic tissues in the target area differed significantly between the two groups (P<0.05). HE staining and vessel staining did not show any injuries of the blood vessels in the pathway of ultrasound ablation in neither of the groups (P>0.05).</p><p><b>CONCLUSION</b>When the target area contains large blood vessels in the pathway of ultrasound ablation, pulsed HIFU can have better therapeutic efficiency to effectively induce tissue damages without affecting the blood vessels.</p>
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Animals , Disease Models, Animal , Extracorporeal Circulation , Hepatic Artery , Pathology , Hepatic Veins , Pathology , High-Intensity Focused Ultrasound Ablation , Methods , Liver , Pathology , SwineABSTRACT
<p><b>OBJECTIVE</b>To explore the feasibility of establishing an isolated porcine liver machine perfusion model and assess its value in high-intensity focused ultrasound studies.</p><p><b>METHODS</b>Twenty-one isolated porcine livers were perfused with autologous blood for 4 h through dual vessels (portal vein and hepatic artery) cannulation using an extracorporeal circulation machine under a sub-normothermic perfusion condition. The perfusion model was assessed by monitoring the liver color, texture, liver weight gain, hemodynamic parameters, color Doppler flow imaging, bile output and histopathology.</p><p><b>RESULTS</b>Nineteen isolated porcine livers were successfully cannulated with dual vessels, and failure of hepatic artery intubation occurred in two porcine livers. After machine perfusion for 4 h, the isolated livers maintained a soft texture with stable hemodynamic levels within relative normal physiological ranges. The bile output was more than 3 ml/h within the initial 3 h of perfusion. Histopathological examination demonstrated no morphological or structural changes of the liver tissues.</p><p><b>CONCLUSION</b>The isolated porcine liver perfusion model is stable and feasible, and can be used for high-intensity focused ultrasound studies.</p>
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Animals , Equipment Design , Extracorporeal Circulation , Methods , Hemodynamics , Liver , Diagnostic Imaging , Liver Circulation , Physiology , Swine , UltrasonographyABSTRACT
Medical treatment technology has made a lot of breakthrough because of the rapid development of the medical devices industrial.Minimally-invasive and noninvasive medicine is the development tendency of the future medicine.To adapt to the needs of the future medicine,Chongqing medical university exerted much efforts on training of minimally-invasive and noninvasive medical talents.We explored and practiced in aspects of fixing educational conception and goal,building curriculum and teaching content,constructing professional teaching team and developing practice and innovation abilities in order to fill the void of personnel training in the minimally-invasive and noninvasive medical field.
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Objective To observed the effect of high-intensity focused ultrasound (HIFU) in combination of submicrobubble on ablation of breast tumor VX2 in rabbits.Methods Submicrobubble was prepared,and the appearance,distribution,diameter,and zeta potential were measured.The rabbits were injected with the tumor tissue suspension in bilateral breast tissues.HIFU(150 W,120 W,5 s,3 s) combined with submicrobubble to damage rabbit breast VX2 tumors.The coagulation necrosis was assessed by HE staining.The grayscale changes of the target area before and after HIFU irradiation were recorded automatically by computer.Results The diameter of the submicrobubble was 498.9 nm on average.HE staining showed the area of coagulation necrosis was significantly larger in the HIFU + submicrobubble group than the HIFU + PBS group.The injury range of 150 W irradiation was larger than that of 120 W irradiation,given the same irradiation time.The injury range of 5 s irradiation was larger than that of 3 s irradiation,given the same irradiation strength.The gray scale change in the target area was significantly higher in the HIFU + submicrobubble group than the HIFU + PBS group.Conclusions The submicrobubble exhibited sound imaging performance,and it can be use in the ultrasound therapeutics in the future.
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<p><b>OBJECTIVE</b>To improve the detection sensitivity of coagulative necrosis caused by high intensity focused ultrasound (HIFU) exposure.</p><p><b>METHODS</b>Sixty rabbits bearing VX2 breast neoplasms at the second bilateral breast were divided randomly into 3 groups (n=20) for targeted HIFU exposure at 90, 120, or 150 W for 3 s. With the right breast neoplasms as the control, the left ones were irradiated following nanoscale bubble injection. The ultrasonograms generated before and immediately after the exposure were analyzed for changes in the gray scale values and for computation of the related functions in the target area. The accuracy and sensitivity of gray evaluation and analysis of the related functions were compared in the detection of coagulative necrosis.</p><p><b>RESULTS</b>Analysis of the related functions of the 120 samples showed an significantly higher accuracy (83.3%) than gray scale-based evaluation (68.3%) in detecting the coagulative necrosis (P<0.05). Under the same irradiation conditions, the mean values of the related function was significantly lower in microbubble group than in the control group (P<0.05).</p><p><b>CONCLUSION</b>Analysis of the related functions of the ultrasonographic data can be used to evaluate the coagulative necrosis in the target exposure area following HIFU with a greater sensitivity and accuracy than gray-scale evaluation.</p>
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Animals , Female , Rabbits , Breast Neoplasms , Diagnostic Imaging , Contrast Media , High-Intensity Focused Ultrasound Ablation , Likelihood Functions , Microbubbles , Nanostructures , Necrosis , UltrasonographyABSTRACT
ObjectiveTo explore the PBL mode in training students' ability,improve the quality of teaching effect,in the teaching of Clinical therapeutic ultrasound and the teaching method based on problems with discussion method.MethodsTo 31 subjects of study who were randomly divided into five groups,each 6 people,a PBL teaching mode was used for 12 periods by proposing and study,group discussion,the whole class exchange and commenting on summary.ResultsThe survey shows that 93.6％ students think the teachers' design has gained their ends,71％ students are impressed by the knowlege and 96.8％ of the students show the good learning attitude,64.5％ of the students raised their interest in learning,which shows teaching results are effective.ConclusionPBL mode is superior to LBL teaching mode in training students' ability,improving the quality of teaching effect.
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Objective To explore the relationship between therapeutic dosage of ultrasound ablation in treatment of uterine fibroids and imaging characteristics of bloody supply of uterine fibroids by color Doppler ultrasound imaging. Methods One hundred and forty-two patients with 168 fibroids were treated by ultrasound ablation. Before treatment, bloody supply of fibroids were classified into grade 0 -4 by ultrasonography. Three patients lost follow-up with contrast MRI exam within 1 month after treatment, so 165 fibroids were enrolled in this study. Bloody supplies were 9 fibroids in grade 0, 34 fibroids in grade 1, 35 fibroids in grade 2, 55 fibroids in grade 3 and 32 fibroids in grade 4. After 1 month treatment, the treated area without blood supply and ratio of ablation were measured by contrast MRI to evaluate the efficacy of thermal ablation and compare status of blood supple based different therapeutic dosage. According to International Reditherapy for Society ( SIR ) standard, adverse effect and score of pain were evaluated. Results ( 1) Ratio of ablation based; ratios of ablation were 79% in grade 0, 89% in grade 1, 92% in grade 2, 86% in grade 3, 71% in grade 4. It reached statistical difference when blood supply of grade 0 compared with those of grade 2 and 3 (P ＜ 0. 05 ) and blood supply of grade 4 compared with those of grade 1, 2, 3 ( P ＜ 0. 05). (2) Factor of energy efficiency:factor of energy efficiency were 13.19 J/mm3 in degree 0, 9. 54 J/mm3 in degree 1, 12. 91 J/mm3 in degree 2, 17. 83 J/mm3 in degree 3 and 28. 10 J/mm in degree 4. Factor of energy of ablation in degree 4 was significantly higher than those in degree 1, 2 and 3 blood supply (P ＜ 0. 05). It exhibit the positive relationship between blood supply and factor of energy of ablation ( r = 0. 354 ,P ＜ 0. 01). ( 3 ) Score of pain and adverse effect: nearly 85% ( 120/142 ) patients could tolerate this treatment very well. Those scores of pain were in range of 0 to 4. All patients did not extend their hospitalization and C to F of SIR standard was not recorded. Conclusion blood supply of myoma measured by ultrasound could predict dosage of ultrasound ablation, it could help select indicated well patients.
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High intensity focused ultrasound (HIFU) is a novel physical tumor therapeutic technology which applies the ultrasound well targeting, focusing, tissue absorbing property, and so on. It focused outer transducer low intensity ultrasound wave and targeted in the tumor, whichcan raise the temperature above 60℃ rapidly and induce tissue irreversible coagulation necrosis, with no damage to the surrounding normal tissue. It is a new physical tumor treatment technology.
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Requirement for Medical English teaching in physical medicine physicians training has been on the agenda to fit the new condition of globalization. According to the development of physical medicine in China and students English level, courses of medical English were set to match the requirements of both scientific research and clinic works. We try to improve students' medical English level through lectures in multimedia classroom and a lot of practical activities after class.
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Objective To assess the influence of pre-exposure to non-ablating ultrasound on the effect of high intensity focused ultrasound(HIFU)ablation.Methods Forty rabbits with transplanted VX2 tumors on their livers were divided into three pre-exposure groups(60 W,80 W and 100 W)and a control group(O W),with 10 rabbits in each group.Each group was pre-exposed to lower intensity focused ultrasound at the corresponding power.From each group,5 rabbits were randomly selected to be exposed to HIFU on the next day.Each group received 14scans.The rabbits were sacrificed 24 h later to take tissue samples for tfipheny tetrazolium chloride(TTC)staining to measure the amount of coagulative necrosis.Hematoxylin and eosin(HE)staining and succinate dehydrogenase (SDH)were also measured to observe the structure and activation of pre-exposed tumors.Results After HIFU exposure,the ablated volumes increased with pre-exposure acoustic intensity,and all volumes were larger than those in the control group.The ablating efficiency in the 100 W group was the highest.The pre-exposure did not itself ablate tumor tissue,but in the 80 W and 100 W groups the structure and activation of the tissues changed.Those in the 60 W group were not obviously altered.Conclusion Prior exposure to non-ablating ultrasound can highly enhance the efficacy of HIFU ablation.
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Objective To observe the pathological regression of rabbit liver after the low-dose irradiation with high intensity focused ultrasound (HIFU), and to explore the role and mechanism of the irradiation in changing acoustic environment of rabbit liver. Methods Pathological study was performed in 10 New Zealand white rabbits, the livers were observed under light and electron microscope. The observation was done immediately after low-dose HIFU irradiation and in 2, 3, 5, 7 days after the low-dose irradiation with HIFU. Results Light microscope changes: Edema existed in hepatocytes after irradiation instantly, congestion and aggravated edema were found at 2-3 days, then the injured cells recovered gradually. Electron microscope changes: Detached endothelial cells of hepatic sinusoid and swelling organelles were observed after irradiation, while 2 or 3 days later, erythrocyte aggregation was found in hepatic sinusoid and cavitation was found in cytoplasm. Thereafter, organelles swelling reduced till resumed to normal. Conclusion Low-dose HIFU irradiation can make corresponding changes to the acoustic environment of rabbit liver.