| To investigate the formation and B-mode ultrasonography monitoring for biological focal region induced by extracorporeal high intensity focused ultrasound,HIFU ablative dosage of different tissue (liver, kidney and muscle),the effect of lipiodol on hepatic HIFU ablative dosage,histopathological changes of hepatic tissue and functional changes of liver and kidney after left hepatic arterial lipiodol embolization and liver HIFU irradiation,70 Nanjiang goats were used for the experiments.1.Research of HIFU biological focal region on goat liverTo explore the formation and B-mode sonography of HIFU biological focal region of liver,18 Nanjiang goats were pulse irradiated by HIFU (1MHz,average acoustic intensity of 5500W/cm2) over different of times (5s,10s,15s and 20s) and depths (30mm and 40mm).After HIFU irradiation,the volumes, maximal cross sectional area of lesions induced by HIFU and value of gray scale, areas of hyperechoic region were recorded.Conclusions: (1) Biological focal region can be formated in goat liver by extracorporeal HIFU irradiation. (2) With the same amount of acoustic intensity and radiating time, the volumes of biological focal regions decreased with the increased depth of radiation. With the given HIFU intensity and irradiated depth kept unchange,the volumes increased with the augmentation in time.(3)Immediately after HIFU radiation,the targeted zone appeared hyperecho,then the values of gray scale of the hyperechoic areas were decreased gradually.(4)After HIFU radiation the area of hyperechoic region augment with lengening radiating time.No significant differences were found between the area of radiating depth of 3cm to that of 4cm.With constant radiating depth and time,the areas of hyperechoic zone detected at 0min,2min,5min were change less. (5)The ratios between hyperechoicareas measured by ultrasound and actual areas were 1.8-3.5.2.Experimential research of HIFU dosage of liver, kidney and muscleTo investigate the destructive dosage of HIFU on liver, kidney and muscle. The liver, right kidney and right thigh of 20 Nanjiang goats were irradiated simultaneously with HIFU.The beginning depth of ablation were under skin of 3-5cm for liver, 3-4cm for right kidney and 3-4cm for muscle of right thigh. The covered ranges were 30mm×10mm×10mm for liver and muscle, 30mm×10mm×5mm for right kidney. The gap for scanning is 5mm.The time of scanning is adjusted for inducing hyperecho. 3 days after HIFU irradiation, all animals were sacrified by overdose of narcotic. The volumes of lesions induced by HIFU were measured by software of GrayVal-pointsData V1.0 version and dosages (energy efficiency factor, J/mm3) were calculated. The histopathological changes of different tissue following HIFU irradiation were observed under light microscope. Conclusions: (1) There were apparent energy-efficiency relation in HIFU- induced necrosis of liver, kidney and muscle. (2)The HIFU ablative dosage of liver of 3cm depth under skin is 16.6±2.72 J/mm3 ,28.3±6.37 J/mm3 for 4cm, 44.7±3.71 J/mm3 for 5cm. (3)The HIFU ablative dosage of kidney were 20.4±5.50 J/mm3 and 32.0±9.10 J/mm3 for 3cm or 4cm depth under skin, respectively.(4)The HIFU destructive dosage for muscle of 3cm and 4cm depth under skin were 3.0±0.90 J/mm3, 5.8±0.71 J/mm3, respectively. (5) With constant average intensity and depth, the ablative dosage of muscle is the lowest and there is no significant difference between liver and kidney. (6) After HIFU irradiation, the histopathological changes of lesions of liver and kidney mainly characterized as completely coagulative necrosis, cell debris, pyknotic nuclei. But for muscle, muscular profibril destruction were seen.3.Establishment of animal model of arteria hepatica sinistra lipiodol embolization 10 goats were divided into two groups: Group 1 was undergone left hepatic arterial lipiodol embolization alone; Group 2 was undergone lefthepatic arterial lipiodol embolization and ligation. Lipiodol was injected transarterial by ventrotomy. The dose of li...
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